JPS61222033A - Optical recording and reproducing device - Google Patents

Abstract

PURPOSE:To correct a signal with an equalizer in matching with the frequency characteristic of a reducing signal by using a switching circuit to change the correction of a frequency characteristic of a reproducing signal thereby reproducing the signal with the same circuit in using two kinds of discs. CONSTITUTION:A control signal switching an output of each equalizer is outputted from a signal processing circuit 31. A signal from a detector 30 and an address signal 80 from control circuits 70, 71 ... 73 and a comparator 16 are inputted to the circuit 31. In reproducing a reproducing exclusive disc, the disc is controlled to pass the equalizer 6 even in reproducing the peripheral and inner circumference of the disc 1. In reproducing the recording and reproducing disc, the address signal section passes through the equalizer 6 and the disc is controlled in the information recording section recorded with contrast so as to pass through each equalizer by using the control signals 70-73 from the address signal. Thus, the same circuit is used for reproduction in using two of discs by changing the correction of the frequency characteristic of the reproducing signal in switch circuits 10, 11-13 and the signal is corrected by each equalizer.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an optical recording and reproducing apparatus that uses a light beam such as a laser to record and reproduce signals on a disk-shaped recording medium, or only reproduces signals, and particularly relates to signal detection thereof. .

2. Description of the Related Art Conventionally, as seen in the example of optical video discs, signals are recorded on a disc-shaped recording medium (hereinafter referred to as a disc) in the form of concentric circles or spiral recording trajectories, such as irregularities or shading. A device that performs high-density recording and reproduction is being considered. In such devices, the recorded signal is
The data is subjected to FM modulation or PCM processing, converted to 2 system numbers, recorded as recording pits on a recording medium, and then reproduced. In addition, in the case of such a recording/reproducing device, the recording pits are generally minute, around 1 μm in diameter, and the recording trench pitch is also about 2 μm or less, so it is difficult to obtain a large-capacity signal recording/reproducing device. I can do it.

As a conventional example of a device having such characteristics, an optical recording and reproducing device for recording and reproducing information signals such as video signals and digital signals on a disk will be described.

FIG. 2 shows its block diagram. The disk 1 is pre-provided with a groove-shaped guide track of optically relevant depth and rotates at a constant rotational speed of, for example, 1200 rpm. 3, 4, 5, and 6 show the structure of the disk 1. FIG. FIG. 3 is a top view of the disk 1, and the disk 1 is preliminarily provided with guide tracks 40 in a concentric or spiral shape (FIG. 3 shows concentric guide tracks as an example). The guide track 40 has an address signal section 42 in which a unique address signal is previously formed in a concave-convex pit structure, and an information recording section 41 for recording the information signal in the form of a sector. Recording is performed along the guide track 40, the address signal is read, and recording is performed in the information recording section corresponding to the address signal. FIG. 3 (3) is an enlarged view of a recording pit, and the black dot a in the guide track 4G indicates an example of a recording pit. FIG. 4 shows a radial cross-section of the disk 1. FIG. The disk 1 is formed of a base member f forming a groove-shaped guide track and a recording surface Q on which the above-described photosensitive recording material is applied. Further, a protective layer is provided on the recording surface 9 as shown in FIG. 40a, 40b, 40c...4
On indicates a guide track, and b indicates a groove. Each guide track 40 has a width W (e.g. W-0.8 μm), a pitch P (e.g. P-1.6 μm), and a depth δ (e.g. δ-0.
, 7μ■). An example of pits recorded on the guide track is shown in a. FIG. 5 shows a plan view of the guide track 40, and FIG. In Fig. 5, 42 is an address signal section in which the address signal etc. are recorded, and 41 is an information recording section for recording information signals etc. The guide track 40 is located in a groove-like structure having a depth δ as shown in FIG. On the other hand, the information recording section 41 is a continuous groove-like structure with a depth δ, and the information signal is recorded in the form of shading. An example of recorded pits is shown in the fifth example.
It is shown in the black dot a of the drawing. The recorded pit portion has a higher density than the unrecorded portion, and the reflectance also changes higher. Therefore, the information signal is reproduced by changes in reflectance.

In FIG. 5 (■), f is a base material portion, Q is a recording surface coated with a photosensitive recording material, and h is a protective layer for protecting the recording surface from dust and scratches.

FIG. 6 shows an example of a recording format of a conventional optical recording/reproducing device. C1 and C2 indicate address signal sections, and in the address signal sections C1 and C2, sector mark signals (A) indicating the position of each sector and address signals (A) of each guide track are included.
(b) is configured. Further, Dl and D2 indicate information recording sections.

The operation of recording and reproducing the address signal or information signal from the disk 1 constructed as described above will be described with reference to FIG.

Reference numeral 2 denotes an optical head that focuses the light beam emitted from the semiconductor laser 3 into a minute beam and irradiates it onto the disk 1 . 4 is a semiconductor laser drive circuit, and when recording, the digital signal, video signal, etc. are inputted from terminal A, and the disc 1 is
When reproducing a signal from a preamplifier 5, the preamplifier 5 receives and amplifies the reproduced light, and supplies it to equalizer circuits 6, 7, 8, and 9.

The equalizer circuit 6.7.8.9 corrects the frequency characteristics of the reproduced signal. When recording and reproducing is performed using a disk that rotates at a constant rotation speed as shown in this embodiment, the frequency characteristics differ between the outer circumference and the inner circumference. FIG. 7 shows an example of frequency characteristics.

In FIG. 7, E indicates the frequency characteristic of the outer circumference, F indicates the frequency characteristic of the outer and middle stations, G indicates the frequency characteristic of the middle and inner circumferences, and H indicates the frequency characteristics of the innermost circumference. Therefore, equalizer circuits 6 and 7
8.9 is a frequency characteristic correction circuit having frequency characteristics such as I, J, and L shown in FIG. 8, respectively, in order to correct the above-mentioned frequency characteristics. - As an example, the equalizer circuit 6 corrects the outer circumference, and the correction characteristics are shown in Figure 8-1.
becomes. In addition, the equalizer circuit 7 is for correcting the outer and middle circumferences, and the correction characteristics are shown in FIG. The correction characteristics are shown in Figure 8.

The outputs of the equalizer circuits 6, 7, 8, and 9 are input to switching circuits 1G, 11, 12.degree. On the other hand, the reproduced signal from the preamplifier 5 is input to an amplifier 17 and a bandpass filter 20, and the output of the amplifier 17 is input to a comparator 19 via an O-bus filter 18. The comparator 19 compares an arbitrary DC voltage input from the terminal M with the output of the low-pass filter 18 to detect an address signal. On the other hand, by inputting the reproduced signal to the band-pass filter 20, the sector mark signal is detected at the output of the band-pass filter 20, and is input to the comparator 22 via the amplifier 21. Comparator 22 is at terminal N
A sector mark signal is output by comparing an arbitrary DC voltage input from the amplifier 21 with the output of the amplifier 21. Comparator 19
The output address signal and the sector mark signal output from the comparator 22 are input to a control circuit 23 composed of a microcomputer or the like, and are then input to the equalizer circuits 6, 7, 8.
Control signals 7G, 71, 72.7 for switching the output of
Outputs 3. These control signals generally read the address signal and output the wJ111 signal depending on the result. 111]1[1[@70, 71.72, 731C, and the reproduced signal output from the equalizer circuit is input to the comparator 16 via the low-pass filter 14 and the amplifier 15. The comparator 16 compares the arbitrary DC voltage input from the terminal O with the output of the amplifier 15, binarizes the information signal, and outputs the binarized information signal from the terminal B.

In the conventional device as described above, when a signal is recorded and reproduced on a recording/reproducing disk, its frequency characteristics depend on the wavelength of the light beam, the numerical aperture of the lens (not shown) used to focus the optical head 2 onto the disk 1, and It is determined by the rotation speed of disk 1. Such devices are required to be miniaturized, and a semiconductor laser is generally used as a light beam generation source.

Therefore, the frequency characteristics when a signal is recorded and reproduced in the information signal recording section are determined by the wavelength of the semiconductor laser 3, the numerical aperture of the optical head 2, and the rotation speed of the disk 1. However, as seen in the address signal section, there are signals that are pre-recorded with a concave-convex pit structure, and address signals, video signals, and other information that are recorded with a concave-convex pit structure from the beginning, as seen in playback-only optical video discs. In the case of read-only disks on which signals are recorded, recording is generally performed in large quantities by recording with a short wavelength laser such as a gas laser and stamping. In the case of such a signal, since it is recorded with a laser having a shorter wavelength than the semiconductor laser 3, the frequency characteristic is better than that of the signal recorded in the information signal recording section.

Problems to be Solved by the Invention In the conventional device, it is difficult to use the same device to play back a recording/playback disk that records and plays back using gradations such as changes in reflectance, and a playback-only disk that has been previously recorded with an uneven pit structure. In this case, since the frequency characteristics differ depending on the recording means, problems arise such as the reproduction signal processing circuit becomes complicated.

It is an object of the present invention to provide an optical recording/reproducing apparatus that can be realized with a simple circuit configuration even for the two types of discs as described above.

Means for Solving the Problems The optical recording and reproducing apparatus of the present invention includes a guide track constituted by a groove-like structure and an information signal such as an address signal, etc., formed in advance on the guide track with a pit structure such as a concave-convex structure. A recording/reproducing disc is provided with an information signal recording section in advance for recording an information signal such as a digital signal based on density of areas and changes in reflectance, or the information signal such as the address signal or digital signal is recorded with unevenness from the beginning. It is configured to irradiate a light beam to a minute beam and irradiate it to a read-only disk on which data is recorded in a discrete pit structure and only performs playback. A discriminating means for detecting which of the two types is used, and a switching means for changing the correction of the frequency characteristics of the reproduced signal are provided. The switching means is configured to change the amount of correction of the frequency characteristic of the reproduced signal between when reproducing a portion recorded with changes in density such as a change in reflectance of the recording/reproducing disk. shall be.

Effect: With this configuration, it is possible to distinguish between a recording/playback disc and a playback-only disc, detect the address signal section of the recording/playback disc, and correct the frequency characteristics of the playback signal using the discrimination signal and detection signal. can be reproduced using the same circuit.

Embodiment FIG. 1 shows an embodiment of the present invention. Components similar to those in FIG. 2 are given the same numbers and detailed explanation thereof will be omitted. 1 is a disk, 2 is an optical head, 3 is a semiconductor laser, 4 is a semiconductor laser drive circuit, 5 is a preamplifier, 6 is an equalizer circuit that corrects the frequency characteristics of the outer circumference, and 7 is an equalizer circuit that corrects the frequency characteristics of the outer and middle circumferences. , 8 is an equalizer circuit for correcting the frequency characteristic of the middle inner circumference, and 9 is an equalizer circuit for correcting the frequency characteristic of the inner circumference. Reference numerals 10, 11, 12, and 13 are switching circuits for switching the outputs of the respective equalizer circuits 6 to 9. 14 is a low pass filter,
15 is an amplifier, 16 is a comparator for binarizing the information signal, and 20 is a band pass filter that detects the sector mark signal, inputs it to the comparator 22 via the amplifier 21, and compares it with the comparison voltage input from the terminal N. The signals are compared and binarized, and a sector mark signal is detected and input to the control circuit 23. 30 is a detector for identifying the disc 1, and its output signal 81 is input to the signal processing circuit 31. As the detector 30, for example, each disc is placed in a disc cartridge made by the same carver, a hole is made in a part of the disc cartridge to operate a microswitch, and the position of the hole is determined to indicate whether the disc is for recording/playback or the disc only for playback. A method is used in which the disc type is determined by which microswitch is activated. The Ill l signal that switches the output of each equalizer is sent to the signal processing circuit 3.
Output from 1. The signal processing circuit 31 includes the detector 3
signal 81 from control circuit 23 and control signal 70 from control circuit 23.
71, 72, 73 and the address signal 80 from the comparator 16, and when playing a read-only disc, the signal is controlled so that it passes through the equalizer 6 even when playing the outer and inner peripheries of the disc 1, When reproducing a recording/reproducing disc, the address signal section 42 is made to pass through the equalizer 6, and the information recording section 41, which is recorded in gradation, is controlled by each equalizer circuit by the control signals 70, 71, 72, 73 from the address signal. control so that it passes through.

With the above configuration, if the device is set to play back the outer periphery of the disk when the power is turned on, and the playback signal is controlled so that it passes through the equalizer circuit 6, then No circuit is required to read various address signals.

In the above embodiment, when reproducing a portion recorded with a pit structure such as unevenness, the amount of correction of the frequency characteristics of the reproduced signal is made smaller than when reproducing a portion recorded with shading.
This can also be switched not to be corrected.

As described in the detailed description of the invention, the optical recording/reproducing apparatus of the present invention includes a discriminating means for detecting whether a vA attached disc is a recording/reproducing disc or a reproduction-only disc, and a discriminating means for detecting whether a disc attached with a vA is a disc for recording/reproducing or a disc for reproduction only, and A switching means for changing the amount of correction of the frequency characteristics is provided, and changes in the reflectance of the recording/reproducing disk are provided when reproducing a read-only disk or when reproducing a portion of the recording/reproducing disk that is pre-recorded with a pit structure such as unevenness. Since the switching means is configured to change the correction amount of the frequency characteristics of the reproduced signal depending on the reproduction of the portion recorded in such gradation, even if two types of the discs are used, reproduction can be performed using the same circuit. In addition, it can be corrected by an equalizer circuit that matches the frequency characteristics of the reproduced signal, and reliability can be improved, which has great practical effects.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the optical recording and reproducing device of the present invention, the second factor is a block diagram of a conventional optical recording and reproducing device, and FIG. 3 is a top view of the disk and its partially enlarged view. FIG. 4 is a radial cross-sectional view of the disk shown in FIG. 3;
Fig. 5 is a plan view and a sectional view of the guide track, Fig. 6 is a diagram showing an example of a recording format, Fig. 7 is a frequency characteristic diagram of a reproduced signal, and Fig. 8 is a correction characteristic diagram of an equalizer circuit. . DESCRIPTION OF SYMBOLS 1... Disk, 2... Optical head, 3... Semiconductor laser, 6.7, 8.9... Equalizer circuit, 10
, 11゜12.13...Switching circuit, 16...Comparator, 23...Control circuit, 30...Detector agent Yoshihiro MorimotoFigure 3Figure 4Figure 5Figure 6 Figure 7Figure 3 71JE1 bed

Claims (1)

[Claims] 1. A guide track composed of a groove-like structure, and an information signal section such as an address signal formed in advance with a pit structure such as a concave and convex structure on this guide track, and a digital signal based on shading such as a change in reflectance. A recording/reproducing disk that has an information signal recording section in advance for recording information signals such as signals, or a recording/reproducing disk on which information signals such as address signals and digital signals are recorded in a discrete pit structure with unevenness etc. from the beginning and which can only be reproduced. The disc is configured to be irradiated with a light beam narrowed down to a minute amount of light and played back on the read-only disc, and a determining means for detecting whether the loaded disc is a recording/playback disc or a read-only disc. , a switching means for changing the amount of correction of the frequency characteristics of the reproduction signal is provided, and the switching means is provided to change the amount of correction of the frequency characteristics of the reproduction signal, and when reproducing a reproduction-only disc or a portion recorded in advance with a pit structure such as unevenness on the recording / reproduction disc, When playing back the recorded part due to changes in reflectance, etc.
An optical recording and reproducing apparatus configured to change the amount of correction of frequency characteristics of a reproduced signal by the switching means. 2. When the switching means is used to reproduce a portion recorded with a pit structure such as unevenness, the amount of correction for the frequency characteristics of the reproduced signal is set to be smaller than when reproducing a portion recorded with shading, or is not corrected. The optical recording/reproducing apparatus according to claim 1, characterized in that the optical recording/reproducing apparatus is configured to switch in the following manner.