JPS61278047A - Disk device - Google Patents

Abstract

PURPOSE:To protect information, and to execute an access at a high speed by sopping an output of a laser, at the time of standly after information is recorded, or after information is reproduced, and also fixing a position of an optical head to its place. CONSTITUTION:When a holding state elapses a prescribed time, a CPU 50 stops a supply of a control signal which is outputted to a reproducing use light quantity setting part 53, and also outputs a stop signal to a driving circuit 51. As a result, a driving signal from the reproducing use light quantity setting part 53 is turned off, and a semiconductor laser 11 stops an output of a laser. Moreover, the driving circuit 51 stops an optical axis by an optical head 3 existing on a linear motor, at the present corresponding track position. Next, when starting the reproduction of information or recording of information, it suffices only to irradiate a laser beam L from its position, therefore, the head can move immediately to a position for an access.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a disk device such as an optical disk device that records or reproduces information on an optical disk using, for example, focused light.

[Technical background of the invention and its problems] In recent years, image information such as documents generated in large quantities is photoelectrically converted by two-dimensional optical scanning, and this photoelectrically converted image information is recorded on an image recording device, or Recently, optical disk devices have been used as image recording devices in image information file devices that can search for and reproduce images as needed, and reproduce and output them as hard copies or soft copies.

Conventionally, such optical disk devices use an optical disk that records information in a spiral manner, and information is recorded or reproduced using an optical head that moves linearly in the radial direction of the optical disk using a linear motor. It has become. In such a device, after recording or reproducing information on an optical disk, the same track is irradiated with a weak laser power to reproduce the information. However, even with a weak laser power, recording information may be destroyed if the same track is irradiated for a long time.

Therefore, from the standpoint of information protection, a method can be considered in which the optical head accesses an unrecorded (no information) area and prohibits laser irradiation on the same track. However,
From the perspective of high-speed information retrieval, there is a drawback that when accessing an unrecorded area, the information recording area must be accessed again, and it takes extra time to search for new information. Ta.

[Object of the invention] This invention was made in view of the above circumstances, and its purpose is to protect information and provide high-speed access during the standby period after information recording or information reproduction. The aim is to provide a disk device that can do this.

[Summary of the invention] In order to achieve the above-mentioned object, the present invention provides a system that, after recording information,
Alternatively, during standby after information reproduction, the output of the laser is stopped and the position of the optical head is fixed in place.

[Embodiment of the Invention] An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 and FIG. 2 show a schematic configuration of an optical disk device of the present invention. That is, the optical disc 1 is
The motor 2 rotates the optical head 3 at a constant linear velocity. The optical disc 1 has a donut-shaped recording film 1a made of a metal coating layer such as tellurium or bismuth coated on the surface of a circular substrate made of, for example, glass or plastic. An optical head 3 for recording and reproducing information is provided on the back side of the optical disc 1. This optical head 3 is constructed as follows. That is, 11
is a semiconductor laser (light source), and this semiconductor laser 11
A diverging laser beam is generated from the. In this case, when writing (recording) information to Recording IIIa of the optical disc 1, laser light whose luminous intensity is modulated according to the information to be written is generated, and the information is read from the recording film 1a of the optical disc 1. During (reproduction), laser light having a constant luminous intensity is generated.

The diverging laser beam generated by the semiconductor laser 11 is converted into a parallel beam by the collimator lens 13 and guided to the polarizing beam splitter 14 . The laser beam guided to this polarizing beam splitter 14 is reflected by this polarizing beam splitter 14, and then 1
passes through the /4 wavelength plate 15 and enters the objective lens 16,
Recording 111 on the optical disc 1 by this objective lens 16
It is focused towards 1a. Here, the objective lens 16 is
It is supported movably in the direction of the optical axis and in the direction orthogonal to the optical axis, and when the objective lens 16 is positioned at a predetermined position, the beam waist of the focused laser beam emitted from the objective lens 16 is The light beam is irradiated onto the surface of the recording film 1a of the optical disc 1, and a minimum beam spot is formed on the surface of the recording film 1a of the optical disc 1. In this state, the objective lens 16 is kept in focus and on track, allowing information to be written and read.

Further, the diverging laser beam reflected from the recording film 1a of the optical disc 1 is converted into a parallel beam by the objective lens 16 when focused, passes through the quarter-wave plate 15 again, and is returned to the polarizing beam splitter 14. . By reciprocating through the 1/4 wavelength plate 15, this laser light has a polarization plane of 9 compared to when it passes through the polarizing beam splitter 14.
The laser light whose polarization plane has been rotated by 0 degrees passes through the polarizing beam splitter 14. The laser light that has passed through the polarizing beam splitter 14 is divided into two systems by a half mirror 17, and the laser light from one of them (track deviation detection system) is directed onto a first photodetector 19 by a first projection lens 18. is irradiated. The first photodetector 19 includes photodetection cells 19a and 19b that convert the light imaged by the first projection lens 18 into electrical signals. The signals outputted by these photodetection cells 19a and 19b are a γ signal and a β signal, respectively.

On the other hand, the laser beam from the other side (defocus detection system) separated by the half mirror 17 is extracted by a knife edge (light extracting member) 20, and only the component passing through an area separated from the optical axis is extracted by the second projection lens. After passing through 21, it is irradiated onto a second photodetector 22. The second photodetector 22 includes photodetection cells 22a and 22b that convert the light imaged by the second projection lens 21 into electrical signals. These photodetection cells 22a122b
The signals output by are α signal and β signal, respectively.
A signal is now output.

Further, as shown in FIGS. 2 and 3, for example, the optical head 3 is fixed to a movable part 5 of a DC linear motor (moving mechanism) 14 that is composed of a movable part and a fixed part, and is movable. The movement of the portion 5 linearly moves the optical disc 1 in the radial direction, that is, in the directions A and B in the drawing. 6 is an optical scale fixed to the movable part 5, and 7 is a detector for detecting the position of the optical scale 6, which is composed of a light emitting part 7a, a light receiving part 7b, etc. It outputs two types of detection signals with different phases in accordance with the movement of the sensor. Further, the moving position of the linear motor 4 is controlled by controlling the amount of current flowing through a movable coil 8 fixed to the movable part 5 by a drive circuit 51 that is driven in response to a signal from a CPU 50, which will be described later. It is something. 9 is the above-mentioned moving coil, and a magnet serving as the iron core of 8.

Among the outputs of the optical head 3, the photodetection cells 19a, 19
The output of b is used for tracking deviation correction and for reproduction signals.

Further, the outputs of the photodetection cells 22a and 22b are used for correcting force focusing (defocusing).

The outputs of the photodetection cells 22a and 22b are also supplied to amplifiers 31 and 32, respectively. The output of the amplifier 31 is supplied to a non-inverting input terminal of a differential amplifier 38. Also,
The output of the amplifier 32 is supplied to the inverting input of the differential amplifier 38.

The differential amplifier 38 generates a defocus detection signal (α-
β) can be obtained.

The output of the differential amplifier 38 is supplied to a waveform shaping circuit 39. This waveform shaping circuit 39 shapes the waveform of the signal supplied from the differential amplifier 38 and supplies it to the drive circuit 40 . This drive circuit 40 includes a coil 24 that drives the objective lens 16 in a direction perpendicular to the recording surface 1a of the optical disc 1 in accordance with a signal supplied from the waveform shaping circuit 39.
By supplying a current corresponding to the objective lens 16
This is to correct forecasting (blurring) by driving the lens.

Further, the outputs of the photodetection cells 19a and 19b are supplied to amplifiers 41 and 42, respectively. The output of the amplifier 41 is supplied to the non-inverting input terminal of a differential amplifier 45, and the output of the amplifier 42 is supplied to the inverting input terminal of the differential amplifier 45. The differential amplifier 45 is configured to obtain a tracking deviation detection signal (γ-δ) by taking the difference between the signals supplied from the amplifiers 41 and 42. The output of the differential amplifier 45 is supplied to a waveform shaping circuit 47. The waveform shaping circuit 47 shapes the waveform of the signal supplied from the differential amplifier 45 and supplies it to the drive circuit 48 . This drive circuit 48 includes a coil 23 that drives the objective lens 16 horizontally in the recording surface 1a of the optical disc 1 in response to a signal supplied from the waveform shaping circuit 47.
By supplying a current corresponding to the objective lens 16
is used to correct tracking deviations.

Further, 50 is a CPU as a control circuit that controls the whole, and drives and controls a drive circuit 51 according to an address signal from an external device (not shown), thereby moving the linear motor 4 and moving the optical head 3. This is to move the vehicle to a predetermined track position.

Further, the CPU 50 outputs a control signal corresponding to a recording signal or a reproduction signal supplied from the external device (not shown) to the recording light amount setting section 52 and the reproduction optical INN group section 3. The reproduction light amount setting section 53 outputs a drive signal to the base of the NPN transistor 64 in response to a control signal supplied from the CPU 50 when reproducing information. The collector of this transistor 64 is grounded via a resistor 65. The transistor 64 performs current amplification in response to a drive signal supplied from the reproduction light amount setting section 53.

As a result, a current flows through the semiconductor laser 11 due to the current amplification of the transistor 64, and the reproduction beam light from the semiconductor laser 11 is irradiated onto the optical disc 1.

Further, the recording light amount setting section 52 controls the CPU 5 during recording.
In response to a control signal supplied from 0, a control signal is output to turn on/off the gate of an FET (field effect transistor) 63 in response to a modulation signal corresponding to the recorded information. The source of this FET 63 is grounded. The drain of this FET 63 and the collector of the transistor 64 are connected to the resistor 62 and the semiconductor laser 11 in common.
and a resistor 61 in order to be connected to a power supply (Vcc). The FET 63 is turned on in response to a control signal supplied from the recording light amount setting section 52, and a predetermined current is supplied to the semiconductor laser 11.

Further, when the CPU 5C) determines by an internal timer (not shown) that a predetermined period of time, for example, 5 minutes has elapsed since the recording or reproduction of information has ended, the CPU 5C) controls the reproduction light amount setting unit 53 By turning off the output of the control signal, the laser beam irradiation by the semiconductor laser 11 is stopped, and by further outputting a stop signal to the drive circuit 51, the linear motor 4 is stopped at the currently corresponding track position. It is something.

Next, the operation in such a configuration will be explained.

For example, the diverging laser beam generated by the semiconductor laser 11 is converted into a parallel beam by the collimator lens 13 and guided to the polarizing beam splitter 14 . The laser beam guided to this polarizing beam splitter 14 is reflected by this polarizing beam splitter 14, and then
The light passes through the quarter-wave plate 15 and enters the objective lens 16, and the recording film 1 of the optical disc 1 is
It is focused towards a.

In this state, when recording information, pits are formed in the tracks on the optical disk 1 by irradiation with a high-intensity laser beam L (recording beam), and when information is reproduced, pits are formed in a track on the optical disk 1 using a low-intensity laser beam L (recording beam). The laser beam L (reproduction beam light) is irradiated. The reflected light from the optical disc 1 for this reproduction beam light is converted into a parallel light beam by the objective lens 16,
The light passes through the quarter-wave plate 15 again and is returned to the polarizing beam splitter 14. As the laser beam travels back and forth through the quarter-wave plate 15, the plane of polarization of this laser beam is rotated by 90 degrees compared to when it is reflected by the polarizing beam splitter 14, and the plane of polarization is rotated by this 90 degrees. The laser light passes through a polarizing beam splitter 14.

The laser beam that has passed through the polarizing beam splitter 14 is divided into two systems by a half mirror 17, and the laser beam from one of them (1 to rack deviation detection system) is transmitted to a first photodetector 19 by a first projection lens 18. irradiated on top. On the other hand, the other side (
A knife etch (light extracting member) 20 extracts only the component of the laser light from the defocus detection system that passes through a region away from the optical axis, and after passing through the second projection lens 21, the laser light is sent to the second photodetector. 22. therefore,
The photodetection cells 20a, 20b, 19a, and 19b output signals corresponding to the irradiated light, and these signals are supplied to amplifiers 31, 32, 41, and 42, respectively.

A normal forcing operation in such a state will be explained. That is, the signals from the amplifiers 31 and 32 are each supplied to a differential amplifier 38. Then, the differential amplifier 38 outputs a defocus detection signal (α-β) obtained by taking the difference between the detection signal from the photodetection cell 22a and the detection signal from the photodetection cell 22b to the waveform shaping circuit 39. do. Then, the waveform shaping circuit 39
The waveform of the supplied signal is shaped and output to the drive circuit 40. Thereby, the drive circuit 40 supplies a predetermined current to the coil 24 according to the signals from the three waveform shaping circuits, and drives the objective lens 16 in the vertical direction to perform force shifting. As a result, the beam spot formed by the objective lens 16 can be set at the optimum position relative to the focus position.

Also, normal tracking operation will be explained. That is, the signal from the amplifier 4.1.42 is fed to a differential amplifier 45. Then, the differential amplifier 45 outputs a tracking deviation detection signal (γ-δ) obtained by taking the difference between the detection signal from the photodetection cell 19a and the detection signal from the photodetection cell 19b. Then, the signal is waveform-shaped by a waveform shaping circuit 47 and supplied to a drive circuit 4.8. Thereby, the drive circuit 48 supplies a predetermined current to the coil 23 according to the signal from the waveform shaping circuit 47, and drives the objective lens 16 in the horizontal direction to perform tracking. As a result, the beam spot formed by the objective lens 16 can be set at the optimum position relative to the tracking position.

Further, during reproduction, the same operation as in the above-mentioned reproduction during recording is performed, and in addition, tracking and force tracking are performed.

When the standby state has elapsed for a predetermined period of time (5 minutes) during recording or reproduction as described above, the CPU 50 stops supplying the control signal to be output to the reproduction light amount setting section 53, and also outputs the control signal to the drive circuit 51. Outputs a stop signal to As a result, the drive signal from the reproduction light amount setting unit 53 is turned off, and the semiconductor sheather 11 stops outputting the laser. Further, the drive circuit 51 stops the optical axis of the optical head 3 on the linear motor 4 at the currently corresponding track position.

As a result, the laser beam irradiation can be stopped with the optical head 3 in a state that substantially corresponds to the track position where the previous recording or reproduction was performed.

This prevents power consumption from being wasted, and the next time you start playing back or recording information, you only need to irradiate the laser beam from that position, so you can immediately move to the position you want to access. Can be done. Therefore, information can be recorded or reproduced immediately, ie, at high speed, without re-accessing from an unrecorded area.

In the above embodiment, a case has been described in which a knife is used to detect out-of-focus, but the present invention is not limited to this, and a detection signal for out-of-focus may be obtained by an astigmatism method. Moreover, although the case where the photodetector is composed of two photodetection cells has been described, the present invention is not limited to this, and the present invention can be similarly implemented using a photodetector having another structure.

[Effects of the Invention] As detailed above, according to the present invention, it is possible to provide a disk device that can protect information and perform high-speed access during standby after information recording or information reproduction. .

[Brief explanation of the drawing]

FIGS. 1, 2, and 3 are diagrams schematically showing the configuration of a disk device showing an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Optical disk (disc), 3... Optical head, 11... Light source (semiconductor laser), 16... Objective lens, 19.22... Photodetector, 19a, 19b,
22a. 22b... Photodetection cell, 23.24... Coil, 3
1.32.41.42...Amplifier, 38.45...
Differential amplifier, 39.47...Waveform shaping circuit, 40,4
8... Drive circuit, 50... CPU, 51... Drive circuit, 52... Light amount setting section for recording, 53... Light amount setting section for reproduction, 63... FET, 64... transistor.

Claims (2)

[Claims] (1) In a disk device that records or reproduces data on a disk using focused light, an optical head consisting of a light source and a focusing means for focusing the light emitted from the light source onto the disk; A moving means for moving an optical head in the radial direction of the disk, a detecting means for detecting light reflected by the disk, a driving means for driving the focusing means in accordance with a detection result by the detecting means, and a data recording means. or when waiting after data playback,
A disk device comprising: means for stopping the moving means; and means for stopping light generation by the light source. (2) The disk device according to claim 1, wherein the moving means is constituted by a linear motor.