JPH01144224A - Information recorder - Google Patents

Abstract

PURPOSE:To prevent information already recorded on a recording medium from being destroyed at the time of a focus servo pulling-in operation by performing the focus servo pulling-in operation at a position where a light emitting means corresponds to the information non-recording part of the recording medium. CONSTITUTION:The title recorder is constituted in such a way that, at the time of performing an initial operation by an information recorder, the light emitting means 6 is moved corresponding to a position where a laser beam can be projected on an information non-recording area (b) by a moving means 5 when the means 6 is not conformed to the position where the laser beam can be projected on the information recording area (a) of the recording medium 1, and after that, the focus servo pulling-in operation is performed. In such a way, it is possible to prevent the information recorded on the recording medium 1 from being destroyed even if a state where the light emitting means 6 crashes with the recording medium 1 is generated accidentally.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to an information recording device such as an optical disk device that records information on, for example, an optical disk.

(Prior Art) Conventionally, in information recording devices such as optical disk devices that use optical means to record information on a recording medium such as a recordable or erasable disk, a laser beam used as a recording means is used. Before emitting light (radiation source), make sure that the cover to avoid shadows on the human body is closed properly so that no laser light leaks outside the device, and that the optical disc is in the specified position. It checks various conditions such as whether the disc is installed or whether the optical disc is rotating, and only when all these conditions are satisfied does initial operations such as emitting laser light and retracting the focus servo begin. It has become.

However, in such conventional optical disk devices,
When performing the focus servo pull-in operation during the initial operation,
No particular consideration is given to the position of the optical head relative to the surface position of the optical disc.

That is, the focus servo pull-in operation is performed regardless of whether the optical head corresponds to an information recording area or an information non-recording area of the optical disk.

Therefore, when performing the focus servo pull-in operation,
If the optical head is in a state corresponding to Z1 in the information recording area of the optical disk, if the focus servo fails to pull in and the optical head collides with the optical disk, J8 will be recorded in the information recording area. There was a problem with the risk of destroying information.

(Problems to be Solved by the Invention) The present invention provides that when the focus servo pull-in operation is performed in the initial operation as described above, if the light emitting means corresponds to the information recording area of a recording medium such as an optical disk, This was done to solve the problem that there is a risk of destroying the information recorded on the recording medium. An object of the present invention is to provide an information recording device that can prevent such problems.

[Structure of the Invention] (Means for Solving the Problems) The information recording device of the present invention includes a light emitting means for emitting laser light to a recording medium that connects an information recording area and an information non-recording area; Information recording means for recording information on the recording medium by controlling light emission of the means; moving means for moving the light emitting means in a radial direction of the recording medium;
a detection means for detecting that the irradiation position of the laser beam by the light emitting means moved by the moving means corresponds to an information-free area of the recording medium;
a first processing means for moving the light emitting means by the moving means when the correspondence is not detected; and a retraction of a focus servo in the light emitting means when the correspondence is determined to be dangerous by the detection means; The second to perform the action
It is characterized by comprising a processing means.

(Function) When the information recording device performs an initial operation, if the light emitting means does not correspond to the position where the laser beam is irradiated onto the information recording area of the recording medium, the information recording area of the recording medium is moved by the moving means. Move it until it corresponds to the irradiation position,
After that, the focus servo pull-in operation is performed. As a result, even if the light emitting means collides with the recording medium, the information recorded on the recording medium will not be destroyed.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 shows a schematic configuration of an information recording device, such as an optical disk device, according to the present invention. In other words, an optical disc (
The recording medium 1 is formed by coating a metal film layer of tellurium, bismuth, or the like in a donut shape on the surface of a circular substrate made of, for example, glass or plastic.

The optical disc 1 has an information recording area a where information is recorded.
and an information non-recording area (a) and (c) in which no information is recorded, which are provided at the inner and outer circumferential portions.

The optical disc 1 is rotationally driven by a spindle motor 2.

The spindle motor 2 outputs a rotational speed signal S1 indicating its rotational speed to a phase comparator 3 forming a PLL (phase locked loop) circuit. This phase comparator 3 has
A reference signal S2 having a predetermined frequency is supplied from a frequency generating means (not shown).

The phase comparator 3 compares the rotational speed signal S1 supplied from the spindle motor 2 with the basic signal S2 supplied from the frequency generation means, and outputs the comparison result to the motor driver 4. It is something to do. That is, when the rotation speed (frequency) of the spindle motor 2 is less than the frequency of the reference signal S2, a signal is output to further increase the rotation speed, and the rotation speed (frequency) of the spindle motor 2 is lower than the frequency of the reference signal S2. If it is too large, a signal is output to lower the rotation speed.

Further, when the phase comparator 3 detects that the frequency (position) of the rotational speed signal S and the basic signal S2 match, it outputs a matching signal S3 indicating this to the control circuit 9. It is supposed to be done.

The motor driver 4 rotates the spindle motor 2 in response to a signal supplied from the phase comparator 3.

An optical head (light emitting means) 6 is disposed below the optical disc 1 . This optical head 6 is for recording or reproducing, and is constructed as follows.

That is, as shown in FIG. 3, 7 is a semiconductor laser oscillator, which is controlled by a laser drive circuit 10. As shown in FIG. This semiconductor laser oscillator 7 emits diverging laser light. In this case, when writing (recording) information onto the recording film of the optical disc 1, the light intensity is changed depending on the information to be written, or a weakened laser beam is generated, and the information is written onto the recording film of the optical disc 1. Read from (play) S
In this case, a laser beam having a constant light intensity is generated.

The diverging laser beam generated by the semiconductor laser oscillator 7 is converted into a parallel beam by the collimator lens 60 and guided to the polarizing beam splitter 61. The laser beam guided to the polarizing beam splitter 6 passes through the polarizing beam splitter 61, enters the objective lens 62, and is focused by the objective lens 62 toward the recording film of the optical disc 1.

Here, the objective lens 62 is supported so as to be movable in its forward axis direction and in a direction perpendicular to the optical axis, and is moved by a drive coil 63. When the objective lens 62 is positioned at a predetermined position, the beam waist of the focused laser beam emitted from the objective lens 62 is projected onto the surface of the recording film of the optical disk 1, and the minimum beam spot is set on the first disk 1. formed on the surface of the recording film. In this state, the objective lens 62 is kept in focus and on track, allowing information to be written and read.

Further, the diverging laser beam reflected from the recording film of the optical disk 1 is converted into a parallel beam by the objective lens 62 when focused, and is returned to the polarizing beam splitter 61 again. This laser light is reflected by the polarizing beam splitter 61 and irradiated onto the photodetector 65 by the projection lens 64.

The photodetector 65 is composed of a number of photodetection cells that convert the light imaged by the projection lens 64 into an electrical signal. The photodetector 65 is configured to output a photoelectrically converted signal to the error amplifier 30 and the adder 31.

A photoelectric conversion element 11 is provided on the opposite side of the recording or reproducing laser beam emission port of the semiconductor laser oscillator 7. The photoelectric conversion cable 11 is irradiated with monitor light from the semiconductor laser oscillator 7, converts the monitor light into an electrical signal, and outputs the electrical signal to the laser drive circuit 10.

The moving mechanism 5 for moving the optical head 6 is composed of, for example, a linear motor (115). That is, the linear motor is composed of a drive coil serving as a movable part and a permanent magnet serving as a fixed part, By exciting the drive coil, the movable part on which the optical disc 6 is mounted is moved in the radial direction of the optical disc 1 (in the direction of arrows A and B in the figure).

Further, the position detector (detection means) 8 is composed of, for example, a photo interrupter, etc., and the initial position of the optical head 6, that is, the irradiation position of the laser beam by the optical head 6 corresponds to the non-information recording area of the optical disc 1. It is located at a position where it can detect what is happening. A position detection signal S4 from the position detector 8 is output to a control circuit 9.

That is, as shown in FIG. 2, when the spot position of the laser beam output from the objective lens 62 of the optical head 6 corresponds to the non-information recording area of the optical disc 1, the upper end of the optical head 6 The position detection signal S4 is detected by blocking the photointerrupter with the detection body 6a provided in the
or is output.

The control circuit (control means) 9 is composed of, for example, a microprocessor, and controls the entire apparatus. The control circuit 9 determines that the optical disc 1 is rotating at a constant rotation based on the coincidence signal S3 from the phase comparator 3, and receives the position detection signal S from the position detector 8.
4, it is determined that the optical head 6 corresponds to the initial position. The control circuit 9 controls the laser drive circuit 10 when the coincidence signal S3 from the phase comparator 3 and the position detection signal S4 from the position detector 8 are supplied during the initial operation upon power-on. One laser beam is emitted from the semiconductor laser oscillator 7. Further, the control circuit 9, at the time of the above-mentioned initial operation,
If the position detection signal S4 is not supplied from the position detector 8, the moving mechanism 5 is controlled to move the optical head 6 in the six directions shown by the arrows until the position detection signal S4 is supplied from the position detector 8. It is supposed to move.

Further, the control circuit 9 generates a ramp wave to move the objective lens 62 and brings it into focus, thereby performing a focus servo pull-in operation.

Further, the laser drive circuit 10 is configured as follows. That is, the error amplifier 13 is supplied with a base voltage S7 from a constant voltage source (not shown).

The error amplifier 13 compares and amplifies the signal supplied from the photoelectric conversion element 11 and the reference voltage S7 supplied from the constant voltage source, and outputs the comparison result to the driver 15.

The driver 15 drives the semiconductor laser oscillator 7 in accordance with the signal supplied from the error amplifier 13. Note that power is supplied to the driver 15 from a power supply device 18 via a switch 17.

On the other hand, the comparator 14 is supplied with a comparison voltage S8 from a constant voltage source (not shown). This comparison voltage S8 is a boundary voltage that, if a voltage higher than this is applied to the semiconductor laser oscillator 7, the information recorded on the optical disc 1 will be destroyed when the laser light is irradiated on the optical disc 1. be.

The comparator 14 compares the voltage of the signal supplied from the adder 3 and the comparison voltage S8 supplied from the constant voltage source (J%), and outputs the comparison result to the AND gate l-16. The AND gate 16 is connected to the control circuit 9.
The output is supplied to the switch 17.

The switch 17 is turned on and off according to the signal from the A N D gate 16, thereby turning on and off the power supply device 18.
The power supplied to the driver 15 is turned on or off.

The error amplifier 30 is supplied with photoelectric conversion signals from, for example, two photodetection cells constituting the photodetector 65. The error amplifier 30 compares and amplifies the signals supplied from the two photodetection cells, and outputs the comparison result to the driver 33 via the control circuit 9 and switch 32.

The switch 32 is turned on and off in accordance with a control signal from the control circuit 9, thereby controlling the error amplifier 30.
It guides or cuts off signals from the driver 33.

The driver 33 is composed of an OP amplifier or the like, and applies current to a drive coil 63 that moves the objective lens 62 in response to a signal supplied from the D/A converter 34 or the differential amplifier 30 via the switch 32. supply.

The D/A converter 34 generates a ramp wave signal under the control of the control circuit 9 and outputs it to the driver 33. This ramp wave signal has a sawtooth waveform and is used to move the objective lens 62 closer to or away from the optical disc 1 .

Further, the adder 31 includes a photodetector 65,
For example, photoelectric conversion signals from two photodetection cells are supplied. This adder 31 adds these two signals and outputs the addition result to the comparator 14 and the control circuit 9. In other words, this adder 31 calculates the total amount of reflected light from the optical disc 1 detected by a plurality of photodetection cells, and is used to detect any abnormal light emission or to determine whether or not a focused state is achieved. It is.

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

For example, when a power switch (not shown) is turned on, the control circuit 9 first controls the motor driver 4 to rotate the spindle motor 2, that is, the optical disc 1.

The control circuit 9 also receives a position detection signal S from the position detector 8.
4 is being supplied, and the position detection signal S4 is detected.
is supplied, it is determined that the initial position of the optical head 6, that is, the position where the laser beam is irradiated by the optical head 6 corresponds to the non-information recording area of the optical disc 1.

As a result of the above check, the position detection signal S from the position detector 8 is
4 (if not supplied, the control circuit 9
is driven to move the optical head 6 in the direction shown by the arrow. Then, when the position detection signal S4 is supplied from the position detector 8, the control circuit 9 stops the movement of the optical head 6 by the movement mechanism 5.

When the control circuit 9 determines whether the optical head 6 corresponds to the initial position and the coincidence signal S3 is supplied from the phase comparator 3, the control circuit 9 causes the laser drive circuit 10 to The semiconductor laser oscillator 7 is driven to generate laser light.

As a result, the optical disc 1 is irradiated with laser light.

In this way, since the semiconductor laser oscillator 7 is driven to emit a laser beam when the optical head 6 is surely aligned with the non-information recording area of the optical disc 1, in the unlikely event that the laser drive circuit Even if the light emission output becomes excessive due to a malfunction such as 10, the information recorded in the information recording area a of the optical disc 1 can be prevented from being destroyed.

In addition, the optical disc 1 has reached a predetermined rotation speed, the relative speed between the optical disc 1 and the optical head 6 is a predetermined speed, and the optical head 6 corresponds to the non-information recording area of the optical disc 1. Laser light is emitted when two conditions are met.

Next, when the laser beam is emitted as described above, the control circuit 9 generates a ramp wave in the output of the D/A converter 34 by sending predetermined data to the D/A converter 34. At this time, the switch 32 is turned off. The ramp wave is supplied to the driver 33, where it is amplified to a certain extent and then supplied to the drive coil 63 of the objective lens 62. As a result, the objective lens 62 is first moved in a direction away from the optical disc 1. When the object lens 62 has moved away by a predetermined distance, the objective lens 62 is moved in a direction toward the optical disk 1.

Furthermore, the light reflected by the optical disk 1 due to the emission of the laser beam is transmitted to the objective lens 62 and the polarizing beam splitter 6.
1 and a projection lens 64 onto a photodetector 65 . Thereby, the photodetector 65 converts the light into an electric signal using two photodetection cells, and supplies the electric signal to the error amplifier 30 and the adder 31.

Thereby, the error amplifier 30 compares and amplifies the signals from the two photodetection cells of the photodetector 65 and supplies the amplified signals to the control circuit 9. Further, the adder 31 adds the outputs of the two photodetection cells and supplies the result to the control circuit 9. As a result, the control circuit 9 determines that the output of the error amplifier 30 is zero and the output of the adder 31 is zero.
If the output of
The output of the ramp wave by 4 is stopped and the switch 32 is turned on. As a result, focus servo is performed according to the error signals obtained by the two photodetection cells.

In this way, the focus servo is pulled in after determining that the optical head 6 corresponds to the non-information recording area of the optical disc 1 and that the first disc 1 is rotating at a predetermined rotation speed. In the unlikely event that a malfunction occurs when controlling the retracting operation of the focus servo, the objective lens 62
Even if a situation such as a collision with the optical disc 1 occurs, the information recorded on the optical disc 1 can be prevented from being destroyed. In addition, since the focus servo pull-in operation is performed after the optical disc 1 reaches a predetermined number of revolutions, even if there is a defective part such as a pinhole on the optical disc 1, accurate focusing force can be achieved. It is something that can be used for shinging.

Further, at the same time that the semiconductor laser oscillator 7 is driven to emit laser light, the monitor light is transmitted to the photoelectric conversion element 11.
is irradiated. Thereby, the photoelectric conversion element 11 converts the monitor light into an electrical signal and supplies it to the error amplifier 13.

Thereby, the error amplifier 13 compares the signal from the photoelectric conversion element 11 and the reference voltage S7, amplifies the difference between them, and supplies the amplified difference to the driver 15. That is, error amplifier 1
3, the voltage of the signal from the photoelectric conversion element 11 is the reference voltage S
If it is lower than 7, the light emitting output is increased and the photoelectric conversion cord 11
If the voltage of the signal from S7 is higher than the voltage S7, the output voltage is adjusted for one week and outputted so as to reduce the light emission output.

The driver 15 converts the received signal into power sufficient to drive the semiconductor laser oscillator 7 and supplies the power to the semiconductor laser oscillator 7 . Thereby, the semiconductor laser oscillator 7 emits the amount of laser light according to the voltage.

Through this operation, the voltage of the monitor signal 6 acts to have the same potential as the reference voltage S7, thereby applying a constant voltage to the semiconductor laser oscillator 7 and keeping its light emission output constant. There is.

Further, the signal indicating light emission from the adder 31 is also supplied to the comparator 14. In the comparator 14, this adder 3
Compare the voltage of the output signal 1 and the voltage of the comparison voltage S8,
As a result of this comparison, if the voltage of the output signal of the adder 31 is higher than the comparison voltage S8, an alarm signal S9 is output.

This alarm signal S9 is supplied to the control circuit 9, and is used under the control of the control circuit 9, for example, to drive an alarm.

Further, the alarm signal S9 is supplied to the AND gate 16, and masks the control signal S5 outputted from the control circuit 9 to drive the semiconductor laser oscillator 7. This mask turns off the switch 17, which in turn turns off the power supply 18.
The power supply to the driver 15 is stopped. As a result, the power supply to the semiconductor laser oscillator 7 is also stopped, and the laser light is turned off.

In this way, if the light emission output of the semiconductor laser oscillator 7 is within the comparison voltage S8, it acts to maintain the predetermined light emission output determined by the reference voltage S7.
If it exceeds 8, the power supply to the driver 15 is stopped and the light emission output of the semiconductor laser oscillator 7 is stopped, so that it is possible to prevent information destruction from expanding due to abnormal light emission of the semiconductor laser oscillator 7. It is possible.

In the above embodiment, the position detector 8 is provided so as to output the position detection signal S4 when the optical head 6 corresponds to an information-free area, or the position sensor 8 is provided so as to output the position detection signal S4 when the optical head 6 corresponds to an information-free area C. It may be provided to output the signal S4.

Furthermore, although a case has been described in which the position detector is constituted by a photoink rubber, the position detector is not limited thereto, and may be constituted by a limit switch.

[Effects of the Invention] As described in detail above, according to the present invention, the light emitting means performs the focus servo retracting operation at a position corresponding to the information-free portion of the recording medium, so that the focus servo retracting operation is performed. It is possible to provide an information recording device that does not destroy information already recorded on a recording medium during operation.

[Brief explanation of the drawing]

The figures show one embodiment of the present invention. Figure 1 is a schematic diagram of the optical disk device, Figure 2 is a diagram showing the mounting position of the position detector, and Figure 3 is the focus servo retracting operation. FIG. 2 is a block diagram showing a control system of FIG. DESCRIPTION OF SYMBOLS 1... Optical disk (recording medium), 2... Spindle motor, 3... Phase comparator, 4... Motor driver, 5... Moving mechanism (moving means), 6... Optical head ( light emitting means), 6a... detection body, 7... semiconductor laser oscillator, 8... position detector (detection means), 9...
Control circuit (first processing means, second processing means), 10.
...Laser drive circuit, 11...Charging conversion element, 1
3゜30...Error amplifier, 14...Comparator, 15.
33...driver, 16...AND gate, 17.
32... Switch, 18... Power supply device, 31...
Adder, 34...D/A converter, 60...Collimator lens, 61...Polarizing beam splitter, 62
...Objective lens, 63...Drive coil, 64...
Projection lens, 65...photodetector. Applicant's agent Patent attorney Takehiko Suzue 1st cause

Claims (2)

[Claims] (1) A light emitting unit that emits a laser beam to a recording medium having an information recording area and an information non-recording area, and information that records information on the recording medium by controlling the light emission of this light emitting unit. a recording means; a moving means for moving the light emitting means in a radial direction of the recording medium; and a position where the laser beam irradiated by the light emitting means moved by the moving means corresponds to an information-free area of the recording medium. a first processing means for moving the light emitting means by the moving means when the correspondence is not detected by the detection means; and a first processing means for moving the light emitting means by the moving means; and a second processing means for performing a pull-in operation of a focus servo in the light emitting means. (2) The information recording device according to claim 1, wherein the recording medium is an optical disc.