JP3060698B2 - Laser light source life judgment device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

(Table of Contents) Industrial Application Field Conventional Technology (FIG. 8) Problems to be Solved by the Invention Means for Solving the Problems (FIG. 1) Action Embodiment (a) Description of First Embodiment ( 2 to 6) (b) Description of the second embodiment (FIG. 7) (c) Description of other embodiments Effect of the Invention

[0002]

The present invention relates to a life determination device determines the laser light source life of the laser light source used in the optical disc apparatus or the like.

In an optical disk device (including a magneto-optical disk device), a laser printer, and the like, reading, writing, and writing of information are performed using a laser light source.

In an apparatus using such a laser light source, it is necessary to output a predetermined optical power from the laser light source. Therefore, before the operation such as when the power is turned on, the drive current of the laser light source is reduced by a predetermined light power. Adjustments are made to obtain power, and this is called light emission adjustment.

However, a laser light source, particularly a laser diode, deteriorates when it is used for a long time or when an overcurrent is applied. When a predetermined optical power is output, a driving current increases, and when the deterioration further proceeds, Even if the maximum current flows, the required predetermined optical power cannot be obtained, and recording and reproduction cannot be performed normally.

Therefore, there is a need for a technique for judging the life of a laser light source in advance.

[0007]

2. Description of the Related Art FIG. 8 is an explanatory diagram of the prior art. FIG.
As shown in FIG. 1A, in an optical disk (magneto-optical disk) device, a laser diode 100 is provided on an optical head 10, and information is recorded by irradiating the rotated optical disk 20 with light from the laser diode 100. The information is reproduced by detecting the change in the properties of the reflected light (light amount, polarization plane, etc.).

When the laser diode 100 deteriorates, as shown in FIG. 8B, the current for obtaining the required read power and write power is changed from I ₁ to I ₃ , I ₂
Increases to I ₄ from further deteriorates, even by passing a maximum current of the device, can not be obtained the required optical power, when writing in margins barely is equal normal light that can not be reproduced data after aging There is a possibility that reading cannot be performed.

For this reason, it is necessary to determine the life of the laser diode 100 in advance.
Measures the current required to cause the laser diode 100 to emit light at a predetermined power, compares the measured current with a predetermined limit current value, and when the current exceeds the limit current value, the laser diode 100
Was determined to have reached the end of its life.

[0010]

However, the prior art has the following problems. There is variation in the performance of the circuit between the devices and the laser light source, and it is difficult to set a limit value.

When the limit value is increased, some laser light sources are deteriorated before reaching the limit value, and normal write / read operations and the like become impossible. It is determined that it can still be used,
It becomes exchange and waste occurs.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a laser light source life determining apparatus capable of improving the life determining accuracy even if the apparatuses have variations.

[0013]

FIG. 1 is a diagram illustrating the principle of the present invention. Claim 1 of the present invention is a laser light source 100 that generates optical power according to a current, and the laser light source 100
And a control unit 44 for instructing a control value of the laser light source 100. In a device that performs a desired operation by the irradiation light of the laser light source 100, the optical power of the laser light source 100 is read, write, or erase, respectively. A non-volatile memory 45 for storing in advance an initial value determined by a control value when the corresponding predetermined value is reached;
When the power of the device is turned on, or the laser light source emits light
A control value when the optical power of the laser light source 100 measured at the time of light emission adjustment at each predetermined timing has reached a predetermined value corresponding to each of read, write, and erase, and a control value of the nonvolatile memory 45. The life of the laser light source 100 is determined by comparing with a corresponding initial value.

[0014]

[0015] Claim 2 of the present invention is based on claim 1,
A control value of the light emission adjustment is stored in the nonvolatile memory 45 every time the light emission is adjusted. In a third aspect of the present invention, in the first aspect, the initial value for comparison is set.
Is a value obtained by adding a correction value to the control value of the nonvolatile memory.
It is characterized by being. According to a fourth aspect of the present invention, when the life of the laser light source 100 is determined by comparing the control value of the light emission adjustment with an initial value, a notification of the life of the laser light source 100 is sent to a higher-level device. It is characterized by notifying.

According to a fifth aspect of the present invention, when the life of the laser light source 100 is determined by comparing the control value of the light emission adjustment with an initial value in the first or second or third or fourth aspects, Information indicating the life is stored in the nonvolatile memory 45.

According to claim 6 of the present invention, in claim 1 or 2 or 3 or 4 or 5, the laser light source 100 is
Optical head 10 for irradiating optical disk 20 with light
, For reading at least information from the optical disc 20.

[0018]

According to the first aspect of the present invention, the control value is determined by the control value when the optical power of the laser light source 100 reaches a predetermined value corresponding to each of read, write, and erase .
A non-volatile memory 45 that stores in advance the initial value obtained ,
The control unit 44 operates when the power of the apparatus is turned on or when a predetermined
A control value measured when the light power of the laser light source 100 becomes a predetermined value corresponding to a read time, a write time, or an erase time, which is measured at the time of adjusting the light emission of the laser light source for each time, Since the life of the laser light source 100 is determined by comparing with the corresponding initial value of the memory 45, even if the performance of the laser light source of each device is different, it is compared with the initial value of the laser light source of that device. Therefore, since the life is determined, it is possible to accurately determine the life according to the performance of each device.

If the operation is performed when the power of the apparatus is turned on,
Before the operation, the life of the laser light source can be determined in advance. Change
Can be performed at predetermined timings when the laser light source
For example, in a library device that does not
However, the life of the laser light source can be periodically determined.

According to the second aspect of the present invention, the control value of the light emission adjustment is stored in the non-volatile memory 45 every time the light emission is adjusted. Useful for investigations. Claim 3 of the present invention
Then, the initial value for comparison adds the correction value,
It can be easily created.

According to a fourth aspect of the present invention, when the life of the laser light source 100 is judged by comparing the control value of the light emission adjustment with the initial value, the life notification of the laser light source is notified to the host device. Can take appropriate measures, such as notification from the operator and stop of operation.

According to a fifth aspect of the present invention, when the life of the laser light source 100 is determined by comparing the control value of the light emission adjustment with the initial value, information indicating the life of the laser light source is stored in the nonvolatile memory 45. Therefore, even if the power is turned off, the history remains, and it is possible to take measures such as stopping the operation of the apparatus in advance.

In the sixth aspect of the present invention, the laser light source 10
0 is provided on the optical head 10 for irradiating the optical disk 20 with light, and is for reading at least information on the optical disk 20. Therefore, the read / write operation of the optical disk device is ensured and the laser light source Can be used to the fullest.

[0024]

【Example】

(a) Description of First Embodiment FIG. 2 is a configuration diagram of one embodiment of the present invention, and FIG. 3 is a rear view of one embodiment of the present invention, showing a magneto-optical disk drive.

In FIG. 2A, reference numeral 1 denotes a magneto-optical disk drive, 10 denotes a movable optical head which irradiates the optical disk 20 with light to perform writing and reading, 10a
Reference numeral denotes a fixed optical head, which houses fixed parts such as a light emitting unit (laser diode) 100, an optical system, a light receiving unit, and the like. Reference numeral 11 denotes a VCM (voice coil motor) coil. Reference numeral 12 denotes a positioner (movable part), which includes the optical head 10 and the VCM coil 11.

13 is an inner peripheral stopper of the positioner 12, 14 is an outer peripheral stopper of the positioner 12,
Reference numeral 15 denotes a spindle motor that rotates the optical disk 20, and reference numeral 16 denotes an external magnet that applies a magnetic field to the optical disk 20 to enable writing.

An optical disk cartridge 2 has an optical disk 20 and is attached to and detached from the magneto-optical disk device 1. In FIG. 2 (B), reference numeral 17 denotes a light emitting unit which is constituted by an LED (light emitting diode), is provided on the positioner 12, and emits light to the semiconductor position detecting element 18, and 18 denotes a semiconductor position detecting element (PSD). This is provided in parallel with the movement path of the positioner 12, detects the light of the light emitting section 17 on the light receiving surface 18a, and generates a current output corresponding to the position (absolute position) of the positioner 12.

In FIGS. 2B and 3, reference numeral 11a denotes VC
An M magnet, which constitutes a VCM (straight motor) together with the VCM coil 11, 12a is a space portion, which allows the positioner 12 to move without the spindle motor 15 being in the way, and 12b is a connecting portion. And V
The CM coil 11 and the optical head 10 are connected, and the space 1
2a.

As shown in the back view of FIG.
A semiconductor position detecting element 18 is fixed on the back surface side opposite to the light irradiation direction of 0, and a light emitting section 17 is provided near the optical head 10 of the positioner 12.

As described above, since the light emitting section 17 is provided independently, the position can be detected even when the optical head 10 does not emit light, the seek operation can be performed, the light emission amount can be sufficiently obtained, and the accurate position detection can be performed. Makes it possible to perform a seek operation.

Moreover, since the optical head 10 is provided on the rear surface side, there is no danger of misdetecting the position due to stray light when the optical head 10 emits light. Further, the optical head 10 has only movable parts such as an objective lens and a track / focus actuator,
The light emitting unit, the light receiving unit, and the optical system are provided in the fixed optical head 10a, and the fixed optical head 10a and the movable optical head 10 are optically coupled, so that the movable optical head 10 can be reduced in weight and can be driven at high speed. Become.

Further, since the positioner 12 is formed so as to straddle the spindle motor 15 from the side, the apparatus can be downsized by using a high-speed VCM. FIG. 4 is a block diagram of one embodiment of the present invention.

In the figure, the same components as those shown in FIGS.
Are indicated by the same symbols.
A voltage conversion circuit, which is provided at both ends of the semiconductor position detecting element 18.
Current output I₁, I_TwoIs the voltage V₁, V_TwoTo convert to
32 is a difference circuit, and the voltage V ₁From the voltage V_Two,
33 for generating a position signal;
Tal) converter that converts analog position signals to digital
It is converted into a signal and input to the control block 44.
You.

Reference numeral 34 denotes a DA (digital / analog) converter for converting a digital drive signal of the control unit 44 into an analog drive signal, and reference numeral 35 denotes a difference circuit for subtracting the drive signal from the position signal to obtain a position error signal. Is a phase compensation circuit, which advances the high frequency component of the position error signal and compensates the phase, and 37 is a VCM drive amplifier, which outputs the VCM coil of the positioner 12 by the output of the phase compensation circuit 36. 11 is driven by current.

Numeral 38 denotes a track servo controller, which controls the optical head 1 based on a track error signal TES generated by the fixed optical head 10a from the reflected light of the movable optical head 10.
Servo control of 0 track actuator, 3
Reference numeral 9 denotes a focus servo control unit which servo-controls a focus actuator of the optical head 10 by a focus error signal FES generated by the fixed optical head 10a from reflected light of the optical head 10.

Reference numeral 40 denotes a DA converter, and a control unit 44
A switch 41 for converting the drive current control value of the laser diode 100 into an analog drive current control amount, a switch 41 for outputting the analog drive current control amount to the laser diode drive amplifier 42 under the control of the control unit 44,
42 is a laser diode drive eye, which drives the laser diode 100 by an analog drive current control amount, 43 is an AD converter, which converts the monitor light amount of the laser diode 100 into a digital value,
This is input to the control unit 44.

Reference numeral 44 denotes a control unit which is constituted by a microprocessor (MPU) and performs seek control, read / write control, and the like by executing a program in accordance with an instruction from a host, and 45 denotes a nonvolatile memory, which is an EEPROM.
(Electrically erasable programmable read-only memory), which stores parameters, etc.
46 is a RAM (random access memory),
The control amount and the like are stored.

In this embodiment, the VCM coil 11 can be driven by a position error signal which is a difference between the drive signal of the control unit 44 and the position signal. That is, the control unit (hereinafter, referred to as a processor) 44 calculates the output value X for the target position r given from the host, and sends the drive signal X to the DA converter 34.
And a position error signal between the position signal of the semiconductor position detecting element 18 generated from the difference circuit 35 and the drive signal X of the DA converter 34 is supplied to the VCM converter 11 via the phase compensation circuit 36 and the VCM drive amplifier 37. Move, seek.

When the position signal from the AD converter 33 reaches the target position, the processor 44 determines that the target position (track) has been positioned, determines that the seek operation has been completed, and ends the seek operation.

After that, the processor 41 turns on the servo of the track servo control unit 38 and the focus servo control unit 39 and performs reading / writing by the optical head 10.
FIG. 5 is a flowchart of the measurement processing at the time of starting the first embodiment of the present invention, and FIG. 6 is a flowchart of the power-on processing of the first embodiment of the present invention.

Referring to FIG. 5, the start-up measurement process will be described. The control unit (hereinafter, referred to as a processor) 44 turns off the switch 41 and sends “0” as a control value to the DA converter 40.
0 "is output, the switch 41 is turned on, and the drive amplifier 4
2 drives the laser diode 100.

The processor 44 includes a DA converter 40
Is increased by 1, and output to the DA converter 40 to drive the laser diode 100 via the switch 41 and the drive amplifier 42.

The processor 44 reads the monitor light amount of the laser diode 100 from the AD converter 43,
It is determined whether the optical power of the laser diode 100 is the specified power, and if it is equal to or lower than the specified power, the process returns to the step.

At this time, as shown in FIG. 8A, in the case of reading / writing, the writing power is larger, so that the specified power is the writing power, and in the case of reading / writing / erasing, the erasing power is the largest. The specified power is the erase power.

In the case of three beams of read / write / erase, the read power, write power and erase power of each laser diode are defined as specified powers.

If the light power of the laser diode 100 is the specified power, the processor 44 stores the current control value of the DA converter in the RAM 46. The processor 44 determines whether or not the operations of the steps 1 to 4 have been repeated 100 times.

When the processor 44 determines that the steps 1 to 4 have been repeated 100 times, the processor 44 turns off the switch 41, calculates an average value Pi of the control values for 100 times stored in the RAM 46, and calculates the average value Pi of the nonvolatile memory (EEPRO).
M) 45 is stored.

In this way, at the time of start-up before shipment of the device, the control value at which the laser diode 100 generates a predetermined optical power is measured and stored in the non-volatile memory 45, and the initial value at the time of operation of the device is compared with the initial value. I do.

Next, the life determining process when the power of the apparatus is turned on after the apparatus is shipped will be described with reference to FIG. When the power is turned on, the processor 44 reads out the average value Pi from the nonvolatile memory (EEPROM) 45 to the RAM 46.

The processor 44 turns off the switch 41, outputs “00” as a control value to the DA converter 40, turns on the switch 41, and drives the laser diode 100 via the drive amplifier 42.

The processor 44 includes a DA converter 40
Is increased by one, the DA converter 40 is output, and the laser diode 100 is driven via the switch 41 and the drive amplifier 42.

The processor 44 reads the monitor light amount of the laser diode 100 from the AD converter 43,
It is determined whether the optical power of the laser diode 100 is the specified power, and if it is equal to or lower than the specified power, the process returns to the step.

If the optical power of the laser diode 100 is the specified power, the processor 44 stores the current control value of the DA converter in the RAM 46. The processor 44 determines whether or not the operation of Steps 1 to 10 has been repeated ten times. If the operation has not been performed ten times, the process returns to Step.

When the processor 44 determines that the operations of steps 1 to 4 have been repeated ten times, the processor 44
The control values for the batches are read, and the average value Pc is calculated. Next, the processor 44 calculates the average value Pc and the initial value Pi.
Is compared with a value obtained by adding the increase limit value (“20”) to the value. If the average value Pc is not equal to or more than (Pi + 20), it is determined that the life of the laser diode 100 is not reached, and the adjustment is terminated. Laser diode 1
Drive 00.

The processor 44 determines that the average value Pc is (Pi
If +20) or more, the life of the laser diode 100 is determined, and the LD (laser diode) life status is returned to the host device.

As a result, the host device can take measures such as stopping the operation and notifying the operator. Furthermore,
The processor 44 sets the LD life flag in the nonvolatile memory 45, and ends the light emission adjustment.

As described above, when the apparatus is started up, the control value at which the laser diode 100 has a predetermined optical power is measured and stored as an initial value. Since the life of the laser diode 100 is determined in comparison with the initial value, accurate life determination according to the characteristics of the laser diode 100 or the like of each device can be performed.

Further, since the measurement of the control value is repeated and the average value is taken, an accurate control value can be measured. The initial value is executed 100 times in order to make the operation more accurate. It is executed 10 times so as not to be late.

Furthermore, since the initial value is stored in the non-volatile memory 45, it can be retained even when the power is turned off, and the initial value is not lost. (b) Description of the Second Embodiment FIG. 7 is a processing flowchart of the second embodiment of the present invention.

The configuration of this embodiment is the same as that of FIGS. 2 to 4, and the start-up process is the same as that of FIG. In this embodiment, even in a magneto-optical disk library device or the like where the power is not easily turned on / off, the life is determined at a constant cycle.

The processor 44 determines whether a command (for example, a spindle-on command) including an LD (laser diode) ON from the host device has arrived or the magneto-optical disk cartridge 2 has been inserted, and turns on the LD (laser diode) ON. If it is determined that a command including the command has arrived or that the magneto-optical disk cartridge 2 has been inserted, the LD emission time and the LD emission frequency are loaded from the nonvolatile memory 45 into the RAM 46.

The processor 44 determines whether or not the loaded light emission time has exceeded 1000 hours.
The process proceeds to step life determination, and if not exceeded, it is determined whether the number of times of light emission loaded exceeds 100 times. If it exceeds, the process proceeds to step life determination, and if not, the process proceeds to step.

The processor 44 executes the LD life check shown in FIG.
The number of times of light emission and the average value of 10 control values in FIG. 6 are stored in the non-volatile memory 45, and the process proceeds to the step.

The processor 44 starts the LD emission time timer and turns on the laser diode 100 (turns on the switch 41). The processor 44, in accordance with a command from a higher-level device,
Execute seek, read, write, etc.

The processor 44 determines whether a command from the host device has received a command including an LD off (spindle off command) or the magneto-optical disk cartridge 2
It is determined whether or not a command including LD off has arrived or if the magneto-optical disk cartridge 2 has not been ejected, and the process returns to the step, and the command returns to step and the magneto-optical disk cartridge 2 has arrived.
Is determined to have been discharged, the laser diode 10
0 is turned off (the switch 41 is turned off).

The processor 44 stops the timer for the LD light emission time, adds the timer value to the light emission time read from the nonvolatile memory 45, and stores it in the nonvolatile memory 45.

Next, the processor 44 adds “1” to the number of times of light emission read from the non-volatile memory 45, stores the result in the non-volatile memory 45, and returns to the step. In this way, even in a magneto-optical disk drive connected to a computer without power off, the laser diode 10
The light emission time of 0 and the number of times of light emission are counted, and a predetermined time (1000
When the number of times reaches a predetermined number of times (100 times), the life of the laser diode 100 in FIG. 6 is checked, and then the laser diode 100 is turned on to perform a predetermined operation.

Therefore, even if the power supply is not turned off, the light emission adjustment and the life check can be performed every fixed light emission time or every fixed number of light emission, and the life of the laser diode 100 can be determined in advance.

(C) Description of Another Embodiment In addition to the above-described embodiment, the present invention can be modified as follows. As described in the magneto-optical disk device, the optical disk device,
It can be applied to other devices such as a laser printer.

In the second embodiment, both the light emission time and the number of times of light emission are determined, but either one may be used. The number of operations in FIG. 5 is set to 100, and the number of operations in FIG. 6 is set to 10. However, the present invention is not limited to this.
Although the predetermined number of times of light emission is 100 times for 000 hours,
Not limited to this.

Similarly, in FIG. 6, the increase limit width is "20", but may be another value. As described above, the present invention has been described with reference to the embodiments. However, various modifications are possible within the scope of the present invention, and these are not excluded from the scope of the present invention.

[0072]

As described above, according to the present invention,
The following effects are obtained. The initial value determined by the control value when the optical power of the laser light source of the device has reached a predetermined value corresponding to reading, writing, or erasing, respectively.
The initial value is stored in advance , and the initial value and the power
Time, or, using a control value obtained by adjusting the light emission of the laser light source for each predetermined timing , to determine the life,
Accurate life determination according to the performance of each device can be performed. Ma
In addition, the life is determined when the light emission is adjusted during operation of the device.
Since there is no need to provide special timing for life judgment,
Service life judgment without reducing access efficiency.
Laser life adjustment has been completed,
With normal power, it is possible to perform normal operation of the device immediately
And stop using it as soon as it is determined to have reached the end of its service life.
Can be

Since the measured initial value is stored in the non-volatile memory, the initial value can be retained even when the power is turned off, and the life can be always accurately determined without losing the initial value.

[Brief description of the drawings]

FIG. 1 is a principle diagram of the present invention.

FIG. 2 is a configuration diagram of an embodiment of the present invention.

FIG. 3 is a rear view of one embodiment of the present invention.

FIG. 4 is a block diagram of one embodiment of the present invention.

FIG. 5 is a flowchart of a measurement process when starting up the first embodiment of the present invention.

FIG. 6 is a flowchart of a power-on process according to the first embodiment of the present invention.

FIG. 7 is a processing flowchart of a second embodiment of the present invention.

FIG. 8 is an explanatory diagram of a conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Magneto-optical disk device 2 Optical disk cartridge 10 Optical head 11 VCM 12 Positioner 20 Optical disk 44 Control part 45 Non-volatile memory 46 RAM 100 Laser diode

Continuation of front page (72) Inventor Shigeru Arai 1015 Uedanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Inside Fujitsu Limited (56) References JP-A-3-183181 (JP, A) JP-A-2-94036 (JP, A) JP-A-3-232287 (JP, A) JP-A-61-141465 (JP, A) JP-A-2-173803 (JP, A) JP-A-58-94140 (JP, U)

Claims (6)

(57) [Claims] An apparatus, comprising: a laser light source that generates optical power according to an electric current; and a control unit that instructs a control value of the laser light source, and performs a desired operation by irradiation light of the laser light source. The non-volatile memory previously stores an initial value determined by a control value when a light power of the laser light source becomes a predetermined value corresponding to a read time, a write time, or an erase time, respectively. When the power of the device is turned on, or when the
A control value when the light power of the laser light source measured at the time of light emission adjustment of the laser light source becomes a predetermined value corresponding to each of read, write, and erase, and a corresponding initial value of the nonvolatile memory. A laser light source life determining apparatus for determining the life of the laser light source. 2. The apparatus according to claim 1, wherein a control value of the light emission adjustment is stored in the nonvolatile memory for each of the light emission adjustments. 3. The method according to claim 1 , wherein the initial value for comparison is the non-volatile data.
2. The apparatus according to claim 1, wherein the control value is a value obtained by adding a correction value to the control value of the memory . 4. The laser device according to claim 1, wherein when the life of the laser light source is determined by comparing the control value of the light emission adjustment with the initial value, a notification of the life of the laser light source is sent to a host device. Laser light source life determination device. 5. The non-volatile memory stores information indicating the life of the laser light source when the life of the laser light source is determined by comparing the control value of the light emission adjustment with an initial value. Item 1. The laser light source life determination device according to item 1, 2, or 3. 6. The optical disk according to claim 1, wherein the laser light source is provided in an optical head that irradiates the optical disk with light, and reads at least information from the optical disk. Laser light source life determination device.