JPS6111941A - Optical recording and reproducing device - Google Patents

Abstract

PURPOSE:To perform stable focus and tracking control and recording and reproducing information on and from a disk by detecting an information signal part corresponding to each recording and reproduction track of the disk, and holding a focus and tracking error signal at a constant voltage in the section of an address information signal. CONSTITUTION:The address information signal part corresponding to each recording and reproduction track of the disk is detected and focus S/H24 and tracking S/H28 which holds the focus and tracking error signal in the section of an address identification signal, a focus error driving signal (c), and tracking error driving signal (f) are switched. Consequently, the evil influence of the superposition of the address information signal on a focus and tracking signal due to the eccentricity and surface undulation of the disk is eliminated to perform stable focus and tracking control, thereby recording and reproducing information on and from the disk 7.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an optical information device related to optical information processing.

2. Description of the Related Art Structures of Conventional Examples and Their Problems In recent years, optical recording/reproducing devices have attracted attention as large-capacity storage media. A conventional optical recording and reproducing device will be explained below.C Fig. 1 shows a schematic diagram of an example of a conventional optical recording and reproducing device, in which 1 is a laser light source, which is not a semiconductor laser but a laser with a constant light intensity. Emits light. A collimator lens 2 converts the laser beam from the laser light source 1 into parallel light. 3 is a polarizing beam splitter, and 4 is a λ/4 wavelength plate. 6 is an objective lens, 6 is an optical pickup 1 that moves the objective lens 5 in the focusing and tracking directions, and 07 is an optical disc (hereinafter referred to as a disc) which is constituted by known driving means such as a voice coil motor.
It has uneven tracks for recording and reproducing information. 8 is a condensing lens, and 9 is a dividing mirror. Reference numeral 10 denotes a focus control photodetector, which is composed of two divided photodetectors. 11
is a focus error signal amplifier that detects and amplifies the focus error signal of the differential output of each of the 10 photodetectors.

12 is a focus compensation circuit including phase compensation.

Reference numeral 13 denotes a focus drive circuit which operates the optical pickup 6 in the focus direction using a focus error signal including phase compensation in step 12. Reference numeral 14 denotes a tracking control photodetector, which is constructed in the same manner as the focus control detector 10. 1
A tracking error signal amplifier 6 detects and amplifies the tracking error signal. Numeral 16 is a tracking compensation circuit including phase compensation, and 17 is a dragging drive circuit which operates the optical pickup in the track direction based on a tracking error signal. A half mirror 18 divides the reflected light from the disk 7. A photodetector 19 receives reflected light from the disk 7. A reproduced signal detector 20 detects track information from the photodetector 19. Reference numeral 21 denotes a recording/reproducing gate detection circuit which detects the address information part of the track of the disk 7 and generates a detection gate for recording and reproduction. Note that the arrow drawn in the optical system section in the figure indicates the optical path of the laser beam.

The operation of the conventional optical recording/reproducing apparatus configured as described above will be explained below.

The laser light emitted from the laser light source 1 passes through the collimator lens 2 and becomes parallel light, which is then sent to the polarizing beam splitter 3 and λμ.
The light passes through the wavelength plate 4 and is focused by the objective lens 5 onto an information track formed on the disk 7 . At this time, since the information track of the disk 7 is rotating with surface runout and eccentricity, in order to focus the laser beam on a predetermined information track, driving is performed based on a focus error signal and a tracking error signal, which will be described later. Voltage optical pickup 6
In addition, the objective lens 5 is operated in the focusing and tracking directions to cause the laser beam to follow a predetermined track. The reflected light from the disk 7 follows the incident optical path and the reverse optical path, passes through the λ/4 wavelength plate twice, becomes 90' polarized light from the incident light, and goes straight through the polarizing beam splitter 3, where it is focused. The light enters the lens 8. The reflected light exiting the condensing lens 8 is split by a splitting mirror 9, one of which is focused on a focus control photodetector 10, and the other light is focused on a tracking control photodetector 14. The focus control photodetector 10 and the tracking control photodetector 14 are two
A focus error signal and a tracking error signal are obtained by an n1 focus error signal amplifier 11 and a tracking error signal amplifier 15, which are composed of a divided photodetector. The focus error signal obtained by the focus error signal amplifier 11 is sent to the focus phase compensation circuit 12 and the focus drive circuit 1.
3, focus control is performed by driving the optical pickup 6 in the focus direction and providing feedback. In addition, with the same configuration, the tracking error signal obtained by the tracking error signal amplifier 16 passes through the tracking phase compensation circuit 16 and the tracking drive circuit 17.
Tracking control is performed by driving the optical pickup 6 in the tracking direction and giving feedback to follow a desired information track. -Blade edge detector 19 is 1
The optical disc 7 is composed of a number of photodetectors that can obtain the amount of reflected light from the information tracks of the disc 7. This track information is detected by the reproduced signal detector 20 from the output of the photodetector 19. A recording/reproduction gate detection circuit 21 generates a recording or reproduction gate for an information track based on the track information signal detected by the reproduction signal detector 2°.

FIG. 2 shows the format of the disc 7. On the reed 7, a large number of recording and reproducing tracks 22 are formed which are arranged concentrically or spirally around the disc 7 that rotates once. Further, in the track 22, there is an address information signal 23 containing sector information for identifying the track on which a video signal or a digital signal is recorded and reproduced, and for dividing the information in the track.

Grooves with unevenness according to sector information are formed.

However, in the above configuration, if the disk 7 has eccentricity, surface runout, etc., the disk 70 address information signal 23 is superimposed on the focus error signal or the tracking error signal, and the focus and tracking control system becomes unstable. There was a problem in that track reproduction and information recording could not be performed accurately.

Purpose of the Invention The present invention solves the above-mentioned conventional problems, and proposes a method for retaining the section where the address information signal is superimposed on the focus error signal and the tracking error signal when the disk has eccentricity or surface runout. However, it is an object of the present invention to provide an optical recording and reproducing apparatus that performs stable focus and tracking control to record and reproduce information.

Structure of the Invention The present invention detects an address information signal section corresponding to each recording/reproduction track of a disk, and maintains the focus and tracking error signal at a constant voltage during the address information signal section by means of maintaining the focus and tracking error signal at a constant voltage. By holding the Z address information signal at 90 degrees, the focus and tracking control system of the Z address information signal are not affected by the eccentricity 9-plane vibration n of the disk, and stable information recording and reproduction is possible.

DESCRIPTION OF EMBODIMENTS FIG. 3 shows a schematic diagram of an optical recording and reproducing apparatus according to a first embodiment of the present invention. Moreover, FIG. 4 is a waveform diagram of each part of the embodiment. Note that, as shown in FIG. 3, parts with the same numbers as in FIGS. 1 and 2 indicate the same parts as in the conventional structure, and a description thereof will be omitted. In FIG. 3, 24 is a focus sample hold circuit (hereinafter referred to as focus S/H
), the output from the focus compensation circuit 12 is held for a certain period of time by a known sample and hold means. 25 is analog switch 1 (hereinafter referred to as analog swr)
26 is analog switch 2 (hereinafter referred to as analog S
(denoted as W2), the output from the focus compensation circuit 12 and the output from the focus S/H 26 are switched. 27
is an inverter circuit that inverts the output of the recording/reproducing gate detection circuit.

Reference numeral 28 denotes a tracking sample and hold circuit C (hereinafter referred to as tracking S/H), which has the same configuration as the focus S/H 26 and holds the output of the tracking compensation circuit 16 for a certain period of time. 29 is an analog switch 3 (hereinafter referred to as analog 5Ws), 30 is an analog switch 4 (hereinafter referred to as analog 5Ws), which has the same configuration as 26 analog SW1, and outputs from the tracking compensation circuit 16 and the tracking S/
Switch the output of H2B.

The operation of the optical recording/reproducing apparatus of this embodiment constructed as described above will be explained below with reference to FIGS. 3 and 4. A laser beam emitted from a laser light source 1 follows an information track 22 on a disk 7 via an optical system. The reflected light from the disk 7 enters the photodetector 19, and the output a of the photodetector 19 has a waveform a containing the address information signal 23 in FIG.
Detect 3. The signal detected by the reproduction signal detector 20 is sent to the information track 22 in the recording and reproduction gate circuit 21.
The address identification signal 23 for identifying the information area and the address information signal 23 is generated. The address identification signal is analog SW1 (
25) and analog 5W3 (29), and becomes a signal switching signal for analog 5W1 (25) and analog 5Wa29. In addition, the address identification signal is the inverter circuit 2.
7. In a similar configuration, the inverted signal is input to analog SW2 (26) and analog SW4, becomes a switching signal, and also serves as a switching signal for focus S/H2.
5 and tracking S/'H28, and becomes a sample and hold timing signal.

Further, the reflected light from the disk 7 is input to a condensing lens 8 and divided by an n1 splitting mirror 9, one of which is focused on a focus control photodetector 10, and the other light is focused on a tracking control photodetector 14. be illuminated. A focus error signal is obtained from the output of the focus control photodetector 10 in a focus error signal amplifier 11, and a focus error drive signal C is obtained through a focus compensation circuit 12 including phase compensation. One of the focus error drive signals C is input to the analog 5W1 (25), and the other is input to the focus S/H 24. The analog 5W1 (25) is turned on by the address identification signal obtained by the recording/reproducing gate circuit 21 when the address identification signal is at a low level, and is turned off when the address identification signal is at Hitch. That is, the focus error drive signal C is inputted to the focus drive circuit 13 by the analog 5W1 (25) at times other than the address identification signal section. The focus S/H 24 holds the focus error drive signal at the falling edge of the address identification signal d, which is inverted by the inverter circuit 27, and obtains the focus drive hold signal d. Focus drive hold signal d
The analog 5W2 (26) turns ON L when the address identification signal Suga is High level, and turns ON L when the address identification signal Suga is LOW.
When w, it becomes OFF. That is, the focus drive hold signal d is generated by the analog 5W2 (26).
The address identification signal portion is input to the focus drive circuit 13. Analog 5W1 (25) and Analog 5W2 (26)
The focus drive signal e obtained in step 1 moves the optical pickup 6 in the focus direction via the focus drive circuit 13.

With the same configuration, a tracking control photodetector 14,
Tracking error signal amplifier 16, tracking compensation circuit 16, analog 5W3 (29), analog 5W4 (3
0), the tracking S/H 2B and the tracking drive circuit 17 drive the optical pickup 6 with the address identification signal part, the tracking error drive signal f, and the tracking drive hold signal q when the address identification signal part is outside. Operate in the track direction.

As described above, according to this embodiment, the focus S/H 24 and the tracking S/H 28 detect the address information signal portion corresponding to each recording/reproduction track of the disk and hold the focus and tracking error signals in the address identification signal section.
By switching the focus error drive signal C and the tracking error drive signal f, it is possible to eliminate the negative effects of superimposition of the address information signal on the focus and tracking signals due to disk eccentricity and surface runout, and to achieve stable focus.
Tracking control is possible, and information can be recorded on and reproduced from the disc 7.

Effects of the Invention The optical recording/reproducing apparatus of the present invention detects the information signal section corresponding to each recording/reproducing track on the disk, and uses means for maintaining the focus and tracking error signals at a constant voltage. By maintaining the focus and tracking error signals at a constant voltage, it eliminates the negative effects of superimposition of the address information signal on the focus and tracking signals due to disk eccentricity and surface runout, enabling stable focus and tracking control, and improving the accuracy of the disk. Information can be recorded and reproduced, and its practical effects are great.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a conventional optical recording/reproducing apparatus, FIG. 2 is a plan view of a disk, FIG. 3 is a schematic diagram of an optical recording/reproducing apparatus according to an embodiment of the present invention, and FIG. The figure is a waveform diagram for explaining the device of the present invention. 1... Laser light source, 2... Collimator lens, 3... Polarizing beam splitter, 4...
.....λμ wavelength plate, 6 .....Objective lens, 6
......Optical pickup, 7...Original disk, 8...Condensing lens, 9...Division mirror, 1o...For focus control photodetector,
11... Focus error signal amplifier, 12...
... Focus compensation circuit, 13. Mountain... Focus drive circuit, 14... Tracking control photodetector, 15... Tracking error signal amplifier, 1
6... Tracking compensation circuit, 17...
- Tracking drive circuit, 18... Half mirror 119... Photodetector 1, 2°... Reproduction signal detector, 21 River... Recording and reproduction gate detection circuit,
22...Track, 23...Address information signal, 24...Pa...Focus sample hold circuit, 25.26...Analog SW1, SW2
．． 27...Dan IA-P, 28...Tracking sample hold circuit, 29.30...Analog SWs, SW4゜Name of agent: Patent attorney Toshi Nakao, 1 person Figure 1 Figure 2 Figure 3 Figure 4 (e) 1

Claims (2)

[Claims] (1) An information part detection means for detecting an address information part corresponding to each recording/reproduction track of an optical disk having concentric or spiral tracks, and a focus or tracking signal applied to a constant voltage in a signal section of the address information part. means for holding the address information section, and the address information section detection section,
An optical recording/reproducing device that performs focus or tracking control using means for holding the focus or tracking signal at a constant voltage. (2) The optical recording and reproducing apparatus according to claim 1, wherein the means for holding the focus or tracking signal at a constant voltage is configured to sample and hold the focus or tracking signal at a voltage immediately before the information section. .