JPH0522305B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a disk recorder using a magneto-optical disk, which has features such as large capacity, high density, rewritability, and high-speed access. It can be used for files, digital audio recorders, etc.

Structure of Conventional Example and Its Problems FIG. 1 shows a partially enlarged view of a conventionally used disk having a tracking guide and an address signal or synchronization signal. FIG. 1a is a sectional view in the radial direction of the disk, where 1 is a disk substrate, 2 is a tracking guide (information writing part), 3 is a recording medium, and a laser beam 4 is incident as shown in the figure. FIG. 1b is a plan view of FIG. 1a, and 5
is a preformat signal such as an address signal or a synchronization signal that can be formed in advance on the tracking guide. FIG. 1c is a sectional view taken along the line AA in FIG. 1b.

FIG. 2 shows an example of a preformatted disk, where 5 is a preformatted synchronization signal and 6 is a recording portion. FIG. 3 is a diagram showing the state in which the disk shown in FIG. 2 is reproduced in the state of signal end recording, and the preformat signal 5 appears every 1/2 rotation of the disk. The recordable portions of the information signal are as shown in FIG. 3, and only the portions excluding the preformat signal 5 can be recorded.

However, this conventional disk drive has the disadvantage that the amount of information that can be written by the user is substantially reduced.

OBJECTS OF THE INVENTION It is an object of the present invention to increase the recording capacity of pregrouped and preformatted magneto-optical disks with a simple configuration.

Structure of the Invention The present invention provides a magneto-optical disk having a tracking guide in the shape of a mechanical groove, and a recording layer having a magneto-optic effect formed on a disk substrate in which a preformat signal is partially recorded on the tracking guide with unevenness. A semiconductor laser using a disk, a collimating lens that converts diverging light from the semiconductor laser into parallel light, and an objective lens that focuses the parallel light on the magneto-optical disk as a minute light spot.
detection means for detecting the recording signal recorded by the semiconductor laser and the preformat signal from the reflected light that has been reflected by the magneto-optical disk and transmitted through the objective lens; and an error signal detection means for detecting a tracking signal, and the detection means includes a separation means for separating the reflected light transmitted through the objective lens, and an error signal detection means for separating the reflected light separated by the separation means into two signals that are orthogonal to each other. a single polarizing prism that separates light into two polarized light components; two photodetectors that respectively receive the two polarized light components; and arranged so that the two polarized light components are respectively focused on the two photodetectors. a single convex lens, a differential amplifier that obtains the recording signal by calculating the difference between the signals detected by the two photodetectors, and a differential amplifier that calculates the sum of the signals detected by the two photodetectors. This is a magneto-optical disk recorder consisting of a summing amplifier that obtains a preformatted signal.

DESCRIPTION OF THE EMBODIMENTS An embodiment of the present invention is shown in FIG. In FIG. 4, the light emitted from the semiconductor laser 8 is made into parallel light by the collimating lens 9, and the half mirror 1
0 and 11, the objective lens 12 causes the disk 1 to be
A minute light spot is formed on 3. disk 13
is a pregrouped and preformatted magneto-optical disk. A magnet 14 generates a bias magnetic field necessary for recording and erasing information signals. The reflected light from the disk 13 is reflected by the half mirror 10 and passes through the cylindrical lens 2.
1 and 22, and enters a multi-division photodetector 23, where focus and tracking error signals are detected. The light reflected by the half mirror 11 is separated into two mutually orthogonal polarized lights by a polarizing prism 15 such as a Rochon prism or a Wollaston prism, and each passes through a convex lens 16 to a photodetector 17.
and 18, and is converted into an electrical signal. The polarizing prism 15 is rotated by 45 degrees around the optical axis with respect to the polarization direction of the reflected light from the half mirror 11. The light detected by the photodetectors 17 and 18 is converted into an electric signal by the head amplifiers 19 and 20, and the photothermomagnetically recorded signal can be detected by taking the difference in the differential amplifier 24, and the sum is taken by the adding amplifier 25. By this, preformat signals such as address signals and synchronization signals can be detected.

The situation described above is shown in FIG. FIG. 5a shows a portion of one track, where A is a track, 5 is a preformat signal, and 26 is an information signal bit recorded photothermally and magnetically. Consider the case where the light spot of the optical system shown in FIG. 4 scans on track A. 5b and 5c show the levels of the electrical signals converted by the head amplifiers 19 and 20 shown in FIG.
In Figure a, the reproduced waveform is shown when there is no information signal bit 26, that is, when no photothermal magnetic recording is being performed, and both of these waveforms have the same phase and the same level. When the information signal bit 26 is present in FIG. 5a, the outputs of the head amplifiers 19 and 20 shown in FIG. 4 have reproduced waveforms as shown by solid lines in FIGS. 5b and 5c. The reproduced waveform based on the information signal bit 26 is the fifth
Figures b and c are out of phase with each other.

FIG. 5d is a signal obtained by taking the difference between FIGS. 5b and 5c, that is, the output signal of the differential amplifier 24 in FIG. The in-phase preformatted signals are canceled by taking the difference, and the reproduced signal of the information signal bit 26, which is in opposite phase, is doubled, and a stable information signal as shown in FIG. 5d can be obtained.

FIG. 5e is a signal obtained by calculating the sum of FIGS. 5b and 5c, that is, the output signal of the summing amplifier 25 in FIG. At this time, information signal bit 2, which is in reverse phase,
The reproduced signals of the fifth
A stable preformat signal as shown in Figure e can be obtained.

Effects of the Invention As described above, according to the present invention, magneto-optical recording can also be performed on preformatted signal bits, and a single polarizing prism and two photodetectors each receiving two polarized light components are used. With the extremely simple configuration of a single convex lens, the optical system can be easily made small and inexpensive, and the recording signal and preformat signal can be separated with high precision.

By developing the present invention, for example, in a permanent recording disk such as a compact disk, a recording material having a magneto-optic effect is sputtered or vacuum-deposited in place of the aluminum deposited on the light-reflecting surface. Based on the same principle, signals can be recorded as RAM on top of ROM, and both signals can be detected independently, making it possible to increase the recording density per disk by up to twice. becomes. Therefore, if the present invention is applied to various data recorders, ROM and RAM can be realized in a single disk, and various applications can be expected.

[Brief explanation of the drawing]

Fig. 1 is a partially enlarged view of a conventionally used disk having a tracking guide and an address signal or synchronization signal, Fig. 2 is a diagram showing an example of a preformatted disk, and Fig. 3 is a diagram showing an example of a preformatted disk. FIG. 4 is a system block diagram showing an embodiment of the present invention, and FIG. 5 is a diagram showing how the same signal is reproduced. DESCRIPTION OF SYMBOLS 1...Disk board, 2...Tracking guide, 3...Recording medium, 4...Laser beam, 5...
...Preformat signal, 6...recording part, 8...
...Semiconductor laser, 9...Collimating lens, 1
0, 11...Half mirror, 12...Objective lens, 13...Disc, 14...Magnet, 1
5...Polarizing prism, 16...Convex lens, 17,
18...Photodetector, 19,20...Head amplifier, 21,22...Cylindrical lens, 23
...Multi-division photodetector, 24...Differential amplifier, 25
...Summing amplifier, 26...Information signal bit.

Claims (1)

[Scope of Claims] 1. A magneto-optical disk substrate having a tracking guide in the form of a mechanical groove, and a recording layer having a magneto-optic effect formed on a disk substrate in which a preformat signal is partially recorded on the tracking guide with unevenness. A semiconductor laser, a collimating lens that converts the diverging light from the semiconductor laser into parallel light, an objective lens that focuses the parallel light on the magneto-optical disk as a minute light spot, and the magneto-optical disk. detection means for detecting a recording signal recorded by the semiconductor laser and the preformat signal from the reflected light that has been reflected and transmitted through the objective lens; and a detection means that detects a focus signal and a tracking signal from the reflected light that has passed through the objective lens. and an error signal detection means for separating the reflected light transmitted through the objective lens, and for separating the reflected light separated by the separation means into two mutually orthogonal polarization components. a single polarizing prism, two photodetectors each receiving the two polarized light components, and a single convex lens arranged so that the two polarized light components are respectively focused on the two photodetectors. , above 2
It consists of a differential amplifier that obtains the recording signal by calculating the difference between the signals detected by the two photodetectors, and a summing amplifier that obtains the preformatted signal by calculating the sum of the signals detected by the two photodetectors. magneto-optical disk recorder.