JPH0547024A - Optical disk device - Google Patents

Abstract

PURPOSE:To obtain a more appropriate laser output by accurately detecting the temperature of an optical disk. CONSTITUTION:Temperature measuring means 4, 6, 8 and 9 measure a center hab 2 of a disk 1, and take it as the initial temperature of the optical disk 1 and after the initial temperature is measured, the temperature in a box 12 is measured. A laser beam output control means 10 controls, based upon the initial temperature, the preset thermal time constant and the temperature in the box 12, the laser beam output irradiated to the optical disk 1. As a result, more accurate temperature of the optical disk is obtained than before, and in addition, optimum laser output is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk device for controlling laser output based on the temperature of a disk.

[0002]

2. Description of the Related Art Conventionally, in an optical disk device,
A disc-shaped recording medium (hereinafter, referred to as an optical disc) is irradiated with a laser beam, and information is recorded on the optical disc by heating by irradiation of the beam.

As described above, in the case of the recording method utilizing the heat of the laser beam, it is preferable to set the intensity of the laser beam according to the surface temperature of the optical disc in order to perform the optimum heating on the optical disc. .. For example, the beam intensity may be weakened when the surface temperature of the optical disk is high, and may be increased when the surface temperature is low.

Therefore, in the conventional optical disk device,
The temperature detected by a temperature sensor provided near the optical disc in the apparatus is input as the temperature of the optical disc, and the laser output is controlled based on the input temperature. Further, in the case of an optical disc housed in a cartridge, the temperature detected by a temperature sensor provided at a position in contact with the cartridge is the temperature of the optical disc.

[0005]

However, the detected temperature of the optical disk in the above case is the ambient temperature in the vicinity of the optical disk or, in the case of the optical disk housed in the cartridge, the temperature of the surface of the cartridge. there were.

Generally, there is a temperature difference between the place where the optical disc is stored and the inside of the optical disc device. When the optical disc is inserted into the optical disc device, the temperature of the optical disc gradually approaches the temperature in the optical disc device, but it takes time until they match. For this reason, the temperature of the optical disc detected as described above is inaccurate until a sufficient time elapses after the optical disc is inserted into the optical disc device. If the output is controlled, it is difficult to obtain the optimum laser beam output.

The present invention has been made to solve the above problems, and an object thereof is to obtain an optical disk device capable of accurately detecting the temperature of a rotating optical disk and setting an optimum laser beam output. ..

[0008]

An optical disk device according to the present invention includes a housing for housing an optical disk, a rotating means for rotating the optical disk, a laser means for irradiating the optical disk with a laser beam, and a housing for the housing. First temperature measuring means for measuring an initial temperature of the optical disk when the optical disk is inserted, and second temperature measuring means for measuring a temperature inside the housing after the initial temperature measurement are preset. The optical disc includes a thermal time constant of the optical disc, the initial temperature, and a laser output control unit that controls the intensity of the laser beam with which the optical disc is irradiated based on the temperature inside the housing. First temperature measuring means and second
The temperature measuring means may also be used as one temperature measuring means.

[0009]

In the present invention, when the optical disk is inserted into the housing, the first temperature measuring means measures the initial temperature of the optical disk and outputs it to the laser output control means. Also, the second
The temperature measuring means measures the temperature inside the housing after the initial temperature measurement and outputs the temperature to the laser output control means. The laser output control means, to which the initial temperature and the temperature inside the housing are input, calculates the temperature of the optical disk over time based on a preset thermal time constant of the optical disk, and also outputs a laser beam according to the temperature of the optical disk. Is output.

[0010]

EXAMPLE An example of the present invention will be described below.
As a typical optical disk used in the optical disk device of the present invention, there is a magneto-optical disk. Therefore, in this embodiment, a magneto-optical disk device will be described.

FIG. 1 is a block diagram of a magneto-optical disk device showing an embodiment of the present invention, and FIG. 2 is a temperature characteristic diagram of the magneto-optical disk. When the magneto-optical disk is higher than the temperature in the disk drive. It is a thing. FIG. 3 is a characteristic diagram of the laser output according to the temperature of the magneto-optical disk.

In the figure, each component of the present apparatus is housed in a housing 12. The sensor vertical drive means 5 vertically lowers the first temperature sensor 4 to bring it into contact with the center hub 2 of the magneto-optical disk 1 when the disk cartridge 3 is inserted into the housing 12, and a laser which will be described later. By inputting a signal from the output control means 10, the first temperature sensor 4 is moved upward and stopped at a predetermined position. The first temperature measuring means 6 measures the initial temperature of the magneto-optical disk 1 from the first temperature sensor 4 brought into contact with the center hub 2 and outputs the measured value to the laser output control means 10. The spindle motor 7 is detachably attached to the center hub 2 of the magneto-optical disk 1 and starts rotating by a load switch (not shown).

The second temperature measuring means 9 measures the temperature in the housing 12 (hereinafter referred to as the drive internal temperature) via the second temperature sensor 8 provided in the housing 12, and outputs the laser. The value is output to the control means 10, and the laser output control means 10 sets the preset thermal time constant of the magneto-optical disk 1 and the initial temperature of the magneto-optical disk 1 measured by the first temperature measuring means 6. Based on, the magneto-optical disk 1 at every time t1
The temperature is calculated from the following formula, and the laser beam corresponding to the calculated value is emitted from the laser means 11. Further, as shown in FIG. 2, when the temperature of the magneto-optical disk 1 decreases with time and becomes almost the same as the internal temperature of the drive, the laser output is set with the internal temperature of the drive as the temperature of the magneto-optical disk 1.

T = T ₀ · e ^−αt1 T: temperature of magneto-optical disk 1 after time t1 T ₀ : initial temperature of magneto-optical disk 1 α: thermal time constant of magneto-optical disk 1 The temperature sensor 4, the first temperature measuring means 6, the second temperature sensor 8 and the second temperature measuring means 9 constitute the temperature measuring means of the present invention.

Next, the operation of this embodiment will be described. When the disk cartridge 3 is inserted into the housing 12,
The sensor vertical drive means 5 lowers the first temperature sensor 4 to bring it into contact with the center hub 2 of the magneto-optical disk 1 in the disk cartridge 3. First temperature measuring means 6
At the same time that the first temperature sensor 4 contacts the center hub 2, the first temperature sensor 4 measures the initial temperature of the magneto-optical disk 1 through the sensor 4 and outputs it to the laser output control means 10. The laser output control means 10 to which the initial temperature is input inputs the drive internal temperature measured via the second temperature sensor 8 from the second temperature measuring means 9, and the first temperature sensor 4 A signal for returning to a predetermined position is output to the sensor vertical drive means 5. At this time, the laser output control means 10
Calculates the temperature of the magneto-optical disk 1 for each time t1 based on the above equation, and outputs the laser output corresponding to the value to the laser means 11. Then, when the calculated temperature of the magneto-optical disk 1 becomes substantially the same as the internal temperature of the drive, the laser means 11 outputs a laser output corresponding to the internal temperature of the drive.
Output to. As can be seen from FIG. 3, when the temperature of the magneto-optical disk 1 is higher than the temperature inside the drive, the laser output is lowered,
On the contrary, when the temperature of the magneto-optical disk 1 is lower, the output is controlled to be increased.

Although the second temperature sensor 8 detects the drive internal temperature in the above embodiment, the same effect can be obtained even if only the first temperature sensor 4 detects the drive internal temperature. Although the thermal time constant of the magneto-optical disk 1 is set in the laser output control means 10 as an example, the thermal time constant may be stored in the magneto-optical disk 1 and read when the laser is driven.

In the present embodiment, the first temperature sensor 4
Since it contacts the center hub 2 of the magneto-optical disk 1, a temperature close to the temperature of the recording surface of the magneto-optical disk 1 can be detected. Further, since the first temperature sensor 4 is separated from the center hub 2 so as not to contact the recording surface after the temperature is detected, the recording surface is not scratched.

[0018]

As described above, according to the present invention, the output of the laser beam is controlled based on the initial temperature of the optical disk and the thermal time constant until the temperature of the optical disk is adjusted to the temperature in the drive. There is an effect that a more accurate laser output can be obtained than the conventional one.

[Brief description of drawings]

FIG. 1 is a block diagram of a magneto-optical disk device showing an embodiment of the present invention.

FIG. 2 is a temperature characteristic diagram of a magneto-optical disk.

FIG. 3 is a characteristic diagram of laser output according to temperature of a magneto-optical disk.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 magneto-optical disk 2 center hub 3 disk cartridge 4 first temperature sensor 5 sensor vertical drive means 6 first temperature measuring means 7 spindle motor 8 second temperature sensor 9 second temperature measuring means 10 laser output control means 11 laser means 12 housing

Claims (1)

[Claims] 1. A housing for housing an optical disk, a rotating means for rotating the optical disk, a laser means for irradiating the optical disk with a laser beam, and an initial stage of the optical disk when the optical disk is inserted into the housing. A first temperature measuring means for measuring a temperature; and a second temperature measuring means for measuring a temperature in the housing after the initial temperature measurement.
Temperature measuring means, laser output control means for controlling the intensity of the laser beam with which the optical disk is irradiated based on a preset thermal time constant of the optical disk, the initial temperature, and the temperature inside the housing. Optical disc device.