JPH02172029A - Optical disk device - Google Patents

Abstract

PURPOSE:To prolong the life of a laser light source and to improve the reliabil ity thereof by detecting the temperature of an optical head when information is written or erased and interrupting the writing or the erasing of the informa tion while the temperature is higher than a reference value. CONSTITUTION:When an optical disk device is started and an instruction for erasing or writing the information is given, the power of the laser light source is set at a high state. Then, a temperature value which makes the power low is inputted to a comparator 6 from an input terminal 7 as the reference value. Thus, when the temperature of the optical head arrives at the reference value, the power is switched to a low state and the writing/erasing of the information is temporarily interrupted while a servo is held. Continuously, the reference value inputted from the terminal 7 is switched to a temperature value which makes the power high and the power is switched to the high state when the temperature of the head 1 is lowered to the reference value. Then, the writing/ erasing is started gain. By repeating such operation, the rise of the temperature of the laser light source is suppressed. Besides, the life thereof is made long and the reliability thereof is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a laser protection function of an optical disk device and a laser output control method of the optical disk device.

[Prior Art] Conventionally, optical disk devices use laser light to erase, write, or read information. Once a laser beam is output for erasing, writing, or reading information, the output level of the laser light source does not change until another operation is performed next time.

[Problems to be Solved by the Invention] In conventional optical disk devices, when writing or erasing is performed over a long period of time, the temperature of the laser light source increases. If the temperature of the laser light source becomes high (this will shorten the life of the laser light source, and in the worst case, it may even destroy the laser light source.In addition, as the temperature of the laser light source increases, the temperature of the optical head will also rise, causing the light This also leads to a decline in the performance of the disk device.

The present invention solves these problems, and aims to provide an optical disk device that can extend the life of a laser light source and improve the reliability of the laser light source.

[Means for Solving the Problems] An optical disc device of the present invention includes: a) a laser light source; b) a laser drive circuit that controls the output of the laser light source; and C) directing laser light emitted from the laser light source to an optical disc. an optical head having a light-receiving element for reading the signal of the light reflected back from the optical disk after condensed irradiation, and d) a servo for receiving the signal of the light-receiving element and performing servo in accordance with the rotation of the disk. g) temperature detection means of the optical head; f) comparison means for comparing the detected temperature with a reference temperature; and d) an output of the laser light source based on the result of the comparison means. It is characterized by comprising a determining means for determining whether or not to perform the switching and outputting a command to the laser drive circuit and the servo circuit.

[Function] According to the configuration of the present invention, when writing or erasing information, the temperature of the optical head is detected using the temperature detection means, the detected temperature is compared with a reference temperature by the comparison means, and the temperature of the optical head is detected by the comparison means. When it is determined that the detected temperature is higher than the reference temperature, the determining means instructs the laser drive circuit to reduce the output of the laser light source and interrupts writing or erasing of information. At the same time, the determining means sends a command to the servo circuit to maintain the position of the optical head. The temperature of the optical head is detected again using the method described above, and when it is determined that the temperature of the optical head has become lower than the reference temperature, the determination means returns the output of the laser light source to the laser drive circuit again, and the servo circuit issue a command to cancel the pause and resume writing or erasing information.

Therefore, according to the present invention, if a certain temperature is set as a reference, the output of the laser light source is temporarily suppressed when the temperature of the optical head becomes higher than the set temperature when writing or erasing information. It is possible to resume writing or erasing information when the temperature of the optical head becomes low again.

[Embodiments] Hereinafter, details of the optical disk device of the present invention will be explained based on embodiments.

FIG. 1 is a block diagram of an optical disk device of the present invention. 1 is an optical head, 2 is a laser light source inside the optical head, 6
4 is a light receiving element for reading the light signal reflected and returned from the optical disk, and 4 is a servo circuit for performing servo based on the received signal.

Reference numeral 5 denotes a temperature detection means, which detects the temperature of the optical head using, for example, a temperature sensor. 6 is a comparator that evaluates the signal detected in 5, and the reference value for comparison is OP.
It is input from U to input terminal 7. 8 is a laser drive circuit that controls the laser output, and 9 is an OPU that determines whether or not to switch the laser output.When switching the laser output, it issues commands to the laser drive circuit 8 and the servo circuit 4. issue.

FIG. 2 is a flowchart showing an example of the operation of the optical disk device according to the present invention. Power of laser light source P
The temperature of one optical head will be explained as T.

When the optical disk device is started and a command to erase or write information is given, the laser light source /<W-P,! ]
″-PH (high power state) is set.

(Step 1) TH (temperature as a reference for weakening the power) is input as a reference value to the comparison means 6 from the input terminal 7, and when the temperature T of the optical head reaches TH (Step 2) ,
Switch P to P L (low power state) and interrupt writing (erasing) of information for - hours while holding the servo. (Step 5) Next, the reference value input from the input terminal 7 is switched to TL, and the temperature Tl of the optical head 1 is changed.
'Monitor and wait for the optical head to cool down.

When T has decreased to TL (step 4), P is reduced to pL
, and start writing (erasing) information again.

(Step 5) When the power P of the laser light source returns to pH, the input terminal 7 is again manually changed to TI (the reference value is TI) and the temperature T of the optical head is monitored.Step 6) Information writing (erasing) ) repeats the loop until it ends.

FIG. 3 shows the temperature T and signal W A of the optical head when the process shown in the chart 70 of FIG. 2 is executed.

FIG. 3 is a diagram showing the relationship between the output P of a laser light source. Here, the signal A shown in FIG. 5(b) is a signal output from the comparator 6, and as shown in FIG. 3(α), when the temperature T of the optical head reaches the reference temperature TH, The output becomes high level, and when the temperature T of the optical head drops to the reference temperature TL, the output becomes low level. Thereafter, each time the signal A switches, the reference temperature also switches between T'H and TL, and each time the temperature T of the optical head matches the reference temperature TH or TL, the level of the signal A also changes to high level and low level output. repeat. During erasing or writing operation, when the level of this signal A is high, well, Fig. 3<g
As shown in >, the output power P of the laser light source is pL, and when the output of the signal A is low level, the output power P of the laser light source is P.

becomes.

[Effects of the Invention] As described above, according to the present invention, the temperature detection means is provided in the optical head portion of the optical disk device, and the temperature of the optical head is monitored using the comparison means, the judgment means, and the output switching means. By doing so, the output of the laser light source is switched, so that the laser light source can be protected, that is, the life of the laser light source can be extended, and damage to the laser light source can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the optical disk device of the present invention, FIG. 2 is a flowchart showing the operation of an embodiment of the optical disk device of the present invention, and FIG. 2g5 (α) to (C) is a diagram showing the relationship between the temperature of the optical head, the output power of the laser light source, and the time chart of the main parts of an embodiment of the optical disk device of the present invention. 1... Optical head 2... Laser light source 3... Light receiving element 4... Servo circuit 5... ......Temperature detection means 6...Comparator 7...Input terminal 8...Laser drive circuit 9...・・・・・・・ 0PU T・・・・・・Temperature of optical head P・・・・・・More than output power of laser light source

Claims (1)

[Scope of Claims] A) a laser light source; b) a laser drive circuit that controls the output of the laser light source; c) condensing and irradiating a laser light emitted from the laser light source onto an optical disk and reflecting it from the optical disk. d) a servo circuit that receives the signal of the light receiving element and performs servo in accordance with the rotation of the disk; and e) temperature detection of the optical head. f) comparison means for comparing the detected temperature with a reference temperature; g) determining whether or not to switch the output of the laser light source based on the result of the comparison means; An optical disc device comprising a drive circuit and a determination means for outputting a command to a servo circuit.