JPS61123031A - Optical output stabilizing device of optical information recording and reproducing device - Google Patents

Abstract

PURPOSE:To record or erase always surely and suitably information on a recording medium by providing a light quantity control means, which controls stably the optical output of a light source to a prescribed value, and an optical beam suppressing means which operates an optical system means in accordance with a command signal without recording neither erasing. CONSTITUTION:The command signal is inputted to an optical beam suppressing circuit 7, and the output signal is connected to an optical system driving circuit 62 to operate the optical system means. Before information is recorded on or erased from a recording medium 2, the optical beam suppressing circuit 7 receives the command signal and is operated, and a defocusing current is flowed t a coil 54 through the optical system driving circuit 62 and the optical beam of a semiconductor laser 1 is defocused and irradiated on the recording medium 2, or a track transversing current is flowed to a voice coil 56 to move the optical beam to a part other than the information recording area on the recording medium. Thereafter, the semiconductor laser 1 emits the optical beam having enough optical output to record or erase information, and the quantity of light is detected by a photodetector 3, and the optical output is adjusted and controlled to a prescribed value automatically through a control circuit 41 and a light source driving circuit 42.

Description

[Detailed Description of the Invention] Non-milk 2 Nirayan 溌1 The present invention is an optical information recording medium that records, reproduces or erases information by condensing a light beam emitted by a light source into a fine beam and irradiating it onto an optical information recording medium. The present invention relates to a light output stabilizing device for a light source of a recording/reproducing device, and more particularly to a light output stabilizing device that stably adjusts and stably controls the amount of strong emitted light used when recording or erasing information to an optimal value.

Sub-Unloading and P0 Problems Optical information recording and reproducing devices record a light beam emitted from a light source such as a semiconductor laser onto a photosensitive optical information recording medium such as a metal thin film, thermoplastics, or magneto-optical storage material. By irradiating the recording medium, it causes physical deformation and changes in physical properties such as reflectance and magnetization direction, thereby recording information with high density or erasing the recorded information as desired. It reproduces recorded information by optically detecting transmitted light. However, optical recording materials used in optically distributed information recording media generally have nonlinear sensitivity characteristics with respect to the amount of light irradiated, for example,
The recording medium is insensitive to weak irradiation light and does not cause any deformation or alteration, and is insensitive to excessive irradiation light intensity.
The thin film of the optical recording material evaporates and scatters, causing a so-called burst phenomenon. Therefore, when recording or erasing information on an optical information recording medium,
The light output of the light beam is adjusted to use a region where the photosensitive characteristics are relatively close to linear and which are above the dead region and do not reach a burst. On the other hand, light sources do not always emit a constant amount of light for a constant light source drive power due to deterioration due to the operating environment temperature and usage time. For example, in the case of a semiconductor laser, when the ambient temperature rises by 1, the laser oscillates. The so-called threshold current that starts the process increases, and the quantum efficiency decreases, causing a decrease in the amount of light for a constant drive current. As described above, in an optical information recording/reproducing device, it is important to stably record or erase information while appropriately adjusting both the photosensitive characteristics of the recording medium and changes in the characteristics of the light source.

For this purpose, various optical output stabilizing devices have been proposed. An example is shown in FIG. 601
602 is a semiconductor laser which is a light source and a PIN photodiode which monitors the light emission from the back side of the semiconductor laser. The photodetection signal is input to the differential amplifier of Ei03 together with the reference voltage Vr, and the comparison output is input to the window comparator 8.
04 and is discriminated based on the upper and lower limit values, and the gate circuit 60
5 to the up/down counter 807 along with the clock pulses of the clock pulse generator 606. Therefore, the counter 607 counts up or counts down according to the input clock pulse according to the output signal of the window comparator 604, and the output digital signal drives the semiconductor laser 801 via the DA converter BO8 and the amplifier 810. The purpose is to increase or decrease the collector current of the transistor 613 to obtain a desired stable optical output from the semiconductor laser 601.

However, according to the conventional optical output stabilization device described in Section 2, the stabilization control of the amount of light emitted from the semiconductor laser, which is the light source, cannot be performed regardless of the presence or absence of a recording medium, the operating state of the optical information recording/reproducing device, or changes in the usage environment. It is carried out continuously all the time. Furthermore, in order to stabilize the optical output at an amount suitable for recording or erasing information, the optical output must be adjusted at least several times at an optical output equal to or higher than that during information recording or erasing, according to the closed control loop that constitutes the optical output stabilizing device. After irradiating the beam,
It is possible to settle on a stable optical output value. For this reason, when a recording medium is set in an optical information recording/reproducing device, a light beam for adjusting the optical output is irradiated onto the recording medium, and unnecessary information is not recorded. It has the disadvantage of being In addition, if the environmental temperature changes or the light source deteriorates for some reason while the device is operating, the optical output stabilization cannot immediately follow up, resulting in incomplete recording or burst portions, resulting in information loss. There were major problems in terms of the reliability and reliability of records.

(7) The present invention has been made in view of the problems that existed in the optical output stabilizing device of the conventional optical information recording and reproducing device as described in 2. Even when an optical information recording medium is set, it is possible to adjust the amount of light with a strong optical output necessary for recording or erasing information without creating unnecessary marks when adjusting the optical output on the recording medium. Furthermore, even when adjusting the light intensity of a strong optical output in the event of an emergency, information can always be reliably and suitably recorded or erased on the recording medium without causing incomplete information recording, erasure, or bursts. Therefore, it is an object of the present invention to realize an optical output stabilizing device that improves the usage efficiency of information recording media and provides a highly reliable optical information recording and reproducing device.

1L11 In order to achieve the above object, the present invention provides an optical information recording/reproducing device that at least detects and photoelectrically converts a light beam emitted by a light source to obtain an electric signal, and uses the photodetection signal as a reference signal. The light output of the light source is set to a predetermined level by performing desired arithmetic processing such as comparison to generate a control signal, storing the signal as necessary, and operating a drive circuit that causes the light source to emit light according to the control signal. a light amount control means for stably controlling the light amount to a value of Even if the light source in conjunction with the light amount control means emits a light beam of sufficient intensity to record or erase information on the recording medium, there will be no deformation or alteration of the recording medium when set according to the input command signal. and a light beam suppressing means for operating the optical system means so as not to cause changes corresponding to recording or erasing. Furthermore, the light beam suppressing means operates the optical system means to change the optical path of the light beam, move the light irradiation onto the recording medium to a place other than the information recording area, or defocus the light beam; It can also be constructed by means of changing the optical path of the light beam. With the above configuration, according to the present invention, when the light amount control means operates to adjust and control the light output of the light source to a strong light output value for recording or erasing information on the recording medium, the input command signal is used. Accordingly, the light beam suppressing means can be operated at an appropriate time to use optical means to move the light beam to a place other than the information recording area, or to defocus the light beam. Therefore, while the light source is stably setting its optical output to a predetermined value, no information is recorded or erased on the recording medium, so there are no residual marks on the recording medium during the adjustment of the optical output, It does not cause incomplete information recording or bursts, and has a deterrent effect.

By providing the signal storage means in the light amount control means, it is possible to store the control information after adjusting the light output, and to have the effect of stably transitioning to closed-loop light output stabilization under normal conditions.

Support-1-1 Hereinafter, the present invention will be described in detail with reference to the drawings. In addition,
Identical members having the same function are marked with the same reference numerals, and their explanations will be omitted.

FIG. 1(A) is a main part configuration diagram showing a schematic configuration of the present invention. 1 is a semiconductor laser light source that sends a light beam to a recording medium 2
At the same time, a part of the light emitted from the back surface of the semiconductor laser is photoelectrically converted by a photodetector 3 such as a PIN photo diode, and is input to the light source drive circuit 42 via the control circuit l, and the light emitted from the back surface of the semiconductor laser l. The light amount control means is configured to adjust and control the drive current of the light source. A moving lens 51 irradiates the recording medium 2 with a light beam from the light source 1, and the reflected light is inputted to a two-split or four-split type photodetector 53 via a half mirror 52. The photoelectrically converted electric signal is processed as a tracking error signal or a focus error signal via the optical system control circuit 81, and then sent to the optical system drive circuit 6.
2, a coil 54 for moving the lens 51 in the focus direction, or a pickup 55 for installing an optical system.
is input to a voice coil 56 that moves the signal in the planar direction (in the case of a disc-shaped recording medium, in the radial direction), thereby configuring the optical system means. Reference numeral 7 denotes a light beam suppression circuit, which is configured to input a command signal and connect an output signal to the optical system drive circuit to operate the optical system means.

According to this embodiment, before recording or erasing information on the recording medium 2, the light beam suppression circuit 7 operates in response to a command signal, and the defocusing circuit 7 is applied to the coil 54 via the optical system drive circuit 62. A current is applied to defocus the light beam of the semiconductor laser 1 to irradiate the recording medium 2, or a track moving current is applied to the voice coil 5B to direct the light beam to a portion of the recording medium other than the information recording area. move it. Afterwards, the semiconductor laser 1 emits a light beam with sufficient intensity for recording or erasing information, detects the amount of light with the photodetector 3, and transmits the light through the control circuit 41 and light source drive circuit 42. It functions to automatically adjust and control the light output value to a predetermined value.

FIG. 1(B) is a detailed circuit diagram embodying the above embodiment. The detection signal of the photodiode PD3, which receives a part of the luminous flux from the laser diode LDI, is sent to the comparison circuit 1.
given to 4. Further, the comparison circuit 14 is supplied with the reproduction reference signal Re ref from the reproduction reference signal generator 19 , and the recording reference signal W * r e f from the recording reference signal generator 20 is supplied to the multiplier 18 . It is given through. In this way, the multiplier 18 only uses the recording reference signal.
This is because the level of the recording reference signal is much higher than the level of the reproduction reference signal (in other words, the amount of laser light during recording is much greater than the amount of laser light during playback). be.

The output of the comparison circuit 14 is input to a window comparator 44 that constitutes the control circuit 15. Each of the comparators constituting the window comparator 14 has a resistor rl.
A reference voltage is input through tr2 and r, l, r2T, and their output is an AND game) 45L, 4
It is given to 5H. Recording data signal (W, DATA
) is the command signal (ADJ・IN) at the OR gate 21.
) and is fed to the multiplier 18 via the filter 23, as well as to the driver 17 for high output light intensity, which will be described later.
Given to H.

On the other hand, the recording gate signal (W, GATE) is OR gate 2
2, it is logically summed with the command signal (ADJ・IN), and is applied to the AND gate 25 via the inverter 24, and
/D is ANDed with the clock signal from the clock pulse generator 46 for counter operation.

It is applied to an AND gate circuit 45L for low output light intensity. Finally, the output of the OR gate 22 is logically ANDed with the clock signal by the AND gate 26, and fed to the AND gate circuit 45 for high output light intensity.
The counter 47L counts up and down the output of the AND gate circuit 45L, and controls U/D for high output light intensity.
The D counter 47H converts the output of the AND gate circuit 45H into 7
Count down, count down. U/D counter 4
? The output of L is converted into an analog signal by a D-A converter 48L, and is sent to a driver 1? for low output light intensity via a Zener diode 31. given to L. Further, the output of the U/D counter 47H is converted into an analog signal by a DA converter 48H, and is applied to a driver 17H for high output light intensity via a Zener diode 32.

As shown in the figure, the driver 17L is composed of an NPN (npn) transistor 33 for low output light intensity drive and a resistor, and the current passing through the transistor 33 is connected to the D-A converter 4.
It is controlled by the output signal of 8L. This controls the amount of light emitted from the laser diode LD during reproduction. Also,
As shown, the driver 17H has a transistor 34 (NPN) for high output light intensity drive, and the current through this transistor 34 is controlled by the output signal of the DA converter 8H. This controls the amount of light emitted from the laser diode LD during recording.

Note that the up/down counter functions as a signal storage means for the control signal.

The second example shows another embodiment of the present invention, in which a command signal is input to a controller 8 consisting of a CPU, etc., and its output is connected to a light source drive circuit 42 and a light beam suppression circuit 7. It is configured to input a set range deviation signal from the control circuit 41 and receive a light beam suppression completion signal from the optical system control circuit 61. According to this embodiment, the light beam suppression circuit 7 operates the optical system means via the optical system drive circuit 82 based on the command signal to prevent a strong light beam from being irradiated onto the recording medium, and also prevents the light beam from being reflected. The light is monitored by the photodetector 53, and the optical system control circuit 61 inputs a light beam suppression completion signal indicating that the optical path change and defocusing have been completed to the controller I/roller 8, and then the controller 8 starts driving the light source. It functions to input a signal to the circuit 42 to advance the control operation of the light source drive circuit 42 for the first time. Further, the control circuit 41 inputs a setting range deviation signal to the controller 8 when the electrical signal inputted by the photodetector 3 deviates from the upper and lower limit set value ranges preset in the control circuit 41, B
This serves to output the USY signal and stop the operation of erasing recorded information.

FIG. 3 shows an embodiment of a circuit for suppressing a light beam according to the present invention, and shows an example in which optical system means is operated to defocus the light beam. 91 is a differential amplifier which inputs the output signal of the 2-split or 4-split photodetector 53, which makes the reflected light from the recording medium emit a focus error signal by optical means and detects it; and 82, the moving lens 51; A driver amplifier that drives the moving coil 54; 93, a switch that opens and closes according to a signal input from the light beam suppressing means; 94, a power source that defocuses the lens 54; 85;
is an adding means for superimposing the output of the power supply 94 on the output of the differential amplifier. According to the six-piece configuration, the output of the power supply 94 is added to the differential amplifier 81 via the switch 93 based on a command from the light beam suppressing means. is superimposed on the output signal of the coil 54.
The lens 51 is moved through the lens 51 to defocus the light beam. Although the above embodiment has been described using defocusing as an example, it goes without saying that this configuration can be similarly applied to the case where the tracking voice coil 56 moves the beam to a location other than the recording area.

FIG. 4 shows another embodiment of the invention. The configuration of this embodiment is such that the control circuit 41, optical system control circuit 61, light beam suppression circuit 7, and controller 8 are implemented by a single CPU 81.
Furthermore, an environmental or semiconductor laser temperature detector 101 is connected, and a timer 102 built into the CPU 81 constitutes an operation elapsed timer.

According to this embodiment, various analog input signals are digitally processed through AD conversion 103 and input to light source driving circuit 41 via I10 interface 104 and DA converter 105.

FIGS. 5(A) and 5(B) are flowcharts illustrating the operation in the embodiment shown in FIG. 4 above. Figure 5 (A) is
This figure shows the process of shifting from optical output stabilization during reproduction to optical output stabilization during recording. During playback, the light emission amount value of the light source is input to the controller 81 and compared with the preset lower and upper limit values (200 in the figure, similarly indicated in parentheses) (201, 202), D-A. Repeat the loop while resetting the conversion output 203, 204)
automatically stabilizes the reproducing light output of the light source. ADJ
When the ADJ signal is received (the ADJ signal is automatically issued when the device is started), the ADJ routine (2
05), the optical system means is moved, the light beam is moved to a non-recording area of the recording medium, the light beam is defocused, etc., and the light quantity is controlled.
It operates the DJ routine 20B), operates the ADJ routine 207) according to the elapsed timer signal, and stabilizes the optical output for recording. FIG. 5(B) shows the ADJ routine described in "2" in more detail.

In summary, according to the present invention, when the optical information recording/reproducing apparatus is started up (when the power is turned on), the ADJ routine of the present invention is activated by a command from an L computer, etc., and the recording light that is expected to be optimal is activated. The optical output is stabilized by storing the output in advance in a storage means (up/down counter), and then during normal information recording, the output from the recording means is obtained, thereby stabilizing the optical output with normal feedback. The light output is stabilized through control.

As described above, according to the present invention, when adjusting and controlling the intensity of the light beam emitted by the light source to an intensity sufficient for recording or erasing information on a recording medium, it is possible to adjust and control the intensity of the light beam emitted by the light source in accordance with the command signal. The means for suppressing the light beam operates to move the light beam outside the information area or defocus it, so that no change corresponding to recording or erasure, such as deformation or alteration, occurs in the recording medium. This prevents unnecessary adjustment marks from being left on the recording medium when adjusting the light intensity, and recording or erasing operations are stopped even in the event of unintentional fluctuations in light output, thereby preventing incomplete information recording. It does not cause erasure, erasure, or bursting, and has a remarkable effect of increasing the usage efficiency of the recording medium. In addition, in the explanation in Section 2, lenses, prisms, and mirrors are used as examples of optical system means, but the invention is not limited to these, and in short, shutters, filters, etc. Of course, the present invention can also be applied by incorporating it into an optical system.

Further, modifications can be easily made within the scope of the idea of the present invention.

[Brief explanation of the drawing]

1A and 1B are block diagrams showing the structure of an embodiment of the present invention, FIG. 2 is a block diagram showing another embodiment of the present invention, and FIG.
The figure is a block diagram showing one embodiment of the light beam suppression circuit of the present invention, FIG. 4 is a block diagram showing another embodiment of the present invention, and FIG.
A) and (B) are flowchart 1 explaining the embodiment of FIG.
・, FIG. 6 shows a configuration diagram of a conventional optical output stabilizing device.

Claims (5)

[Claims] (1) In an optical information recording/reproducing device that records, reproduces, or erases information by irradiating a light beam emitted by a light source such as a semiconductor laser onto an information recording medium, at least one of the light beams emitted by the light source is a light amount control means for obtaining a control signal by photoelectrically converting the light source and controlling a light source drive circuit using the control signal to obtain a stable light output; A light source emits a light beam of sufficient intensity to record or erase information on the recording medium in conjunction with an optical system means for adjusting and irradiating a light beam to a desired position and a light amount control means. and a light beam suppressing means for operating the optical system means so as not to record or erase any information on the recording medium in response to a command signal inputted thereto. Output stabilizer. (2) The optical information recording/reproduction according to claim 1, wherein the light amount control means is a control means comprising a signal storage means at at least one location of a control loop that transmits a photoelectrically converted electric signal. Equipment light output stabilization device. (3) Optical output stabilization of the optical information recording/reproducing apparatus according to claim 1, wherein the optical system means is an optical system means equipped with a moving mechanism that moves the light beam at least in the plane direction of the recording medium. Device. (4) The optical system means includes at least a focus adjusting means for adjusting the focus of the light beam emitted by the light source to a desired degree of convergence and irradiating it onto the recording medium, and the light beam suppressing means Claim 1, wherein at least the optical system means defocuses the light beam to prevent the light beam from recording or erasing on the medium.
An optical output stabilizing device for an optical information recording/reproducing device according to paragraph 1. (5) The light beam suppressing means suppresses recording or erasing on the medium by the light beam by causing at least the optical system means to move the light beam to a location other than the information recording area of the recording medium. 2. An optical output stabilizing device for an optical information recording/reproducing device according to claim 1.