JPH03217913A - Method and device for compulsory cooling - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention is applicable to, for example, an optical head of an optical disk device.
The present invention relates to a forced cooling device that forcibly cools the temperature of an object, which increases as the temperature of the surrounding atmosphere increases, to a predetermined temperature during driving, and a cooling method thereof.

(Prior Art) FIG. 2 is a diagram for explaining a cooling method in a conventional optical disk device, in which 1 is a semiconductor laser, 2 is an optical head, 3 is an optical disk, 4 is a door actuator, and 5 is a cooling method for a conventional optical disk device.
is a spindle motor, 6 is a case, and 7 is a fan.

In an optical disk device, a laser beam emitted from a semiconductor laser 1 is transmitted through an optical system (not shown) of an optical head 2.
It is used by condensing the light onto the optical disk 3 which is a storage medium. The optical head 2 can be moved in the radial direction of the optical disk 3 by a head actuator 4, allowing access to the laser focusing spot. Further, the optical disk 3 is rotated by a spindle motor 5, so that the laser focused spot can be accessed in the longitudinal direction of the track. Data is recorded and reproduced by appropriately controlling the power of this laser focusing spot.

At this time, heat is generated as the head actuator 4 and spindle motor 5 operate, and the temperature inside the case 6 rises, causing the temperatures of the optical head 2 and the semiconductor laser 1 to rise.

Furthermore, the temperature of the optical head 2 and the semiconductor laser 1 also increases due to heat conduction from the head actuator 4.

Generally, it is known that the lifetime of the semiconductor laser 1 becomes shorter as the package temperature increases during use, that is, as the light emitting part temperature increases during use. Therefore, in conventional optical disk devices, the fan 7
It was configured to forcibly ventilate the air inside Kes 6 with the outside air using a.

(Problems to be Solved by the Invention) The conventional cooling method described above only uses forced ventilation using the fan 7 and does not perform active cooling, so the operating temperature of the semiconductor laser 1 is set to a temperature several degrees higher than the outside temperature. There is a drawback that the life of the semiconductor laser 1 is shortened when used in a high-temperature environment.

In addition, in a high-speed optical disk device, the head actuator 4 and spindle motor 5 generate a large amount of heat, and the semiconductor laser 1 itself also generates a large amount of heat, so the temperature of the light emitting part of the semiconductor laser 1 becomes higher and its life becomes extremely short. was there.

Furthermore, in the target disk where parallel recording and playback is performed using a multi-beam semiconductor laser that emits multiple laser beams, the multi-beam semiconductor laser has as many heat sources as the number of beams in close proximity, so the temperature of the light emitting part increases. This has the drawback that the rise becomes extremely large and the life of the multi-beam semiconductor laser becomes extremely short.

The present invention has been made in view of the above circumstances, and its purpose is to cool down the temperature of an object, which increases during use, to a predetermined temperature while taking into account the temperature difference with the outside air temperature, and to cool down objects such as semiconductor lasers, etc. Another object of the present invention is to provide a forced cooling device and a cooling method thereof, which can improve the lifespan of a part to be cooled whose lifespan is easily affected by use in high temperature conditions.

(Means for Solving the Problems) In order to achieve the above object, claim (1) includes a forced cooling unit that cools a cooling target part by human power of a drive signal, and a forced cooling unit that detects the ambient temperature in the vicinity of the cooling target part. a first temperature sensor that detects the temperature of the cooling target part, a second temperature sensor that detects the temperature of the cooling target part, a first detection signal from the first temperature sensor, and a second detection signal from the second temperature sensor. , when the first detected temperature value based on the first detection signal exceeds the first set temperature value, according to the comparison result between the second detected temperature value based on the second detection signal and the second set temperature value. and a cooling control section that controls the output of the drive signal.

Further, according to claim (2), the atmospheric temperature near the cooling target part is detected, the temperature of the cooling target part is detected, and a first detection temperature value indicating the detected neighboring atmospheric temperature is set in advance. A second set temperature value is generated when the first detected temperature value exceeds the first set temperature value, and this second set temperature value and the detected temperature of the cooling target part are compared. , and if the second detected temperature value exceeds the second set temperature value, a drive signal is generated according to the difference between the second detected temperature value and the second set temperature value. is sent to the forced cooling section to forcibly cool the cooling target section to the second set temperature value.

(Function) According to claim (1), the first temperature sensor disposed near the part to be cooled detects the ambient temperature in the vicinity of the part to be cooled, and the first temperature sensor indicates the first detected temperature value. 1 detection signal is output, and this is input to the cooling control section.

On the other hand, the second temperature sensor detects the temperature of the part to be cooled that has become higher than the nearby ambient temperature due to driving, and
A second detection signal indicating this second detected temperature value is output, and this is input to the cooling control section.

In the cooling control section, a first detected temperature value based on the inputted first detection signal and a first set temperature value are compared. As a result, if the first detected temperature value exceeds the first set temperature value, then the second detected temperature value based on the second detection signal and the second set temperature value are determined.
A comparison is made with the set temperature value. The cooling control section controls the output of a drive signal to the forced cooling section according to the comparison result.

The forced cooling unit starts a cooling operation by manual power of a drive signal, and thereby the cooling target part is forcibly cooled.

According to claim (2), the second set temperature value of the predetermined value is generated only when the first sensed temperature value exceeds the preset first set temperature value. Here, a comparison is made between the generated second set temperature value and a second detected temperature value indicating the detected temperature of the cooled part, and if the second detected temperature value exceeds the second set temperature value, both A drive signal corresponding to the difference is output to the forced cooling section. As a result, forced cooling of the part to be cooled is started, and this cooling operation is continued until the detected temperature of the part to be cooled, that is, the second detected temperature value becomes equal to the second set temperature value.

(Embodiment) FIG. 1 is a configuration diagram showing an embodiment of a forced cooling device employing the method of the present invention, and shows an example of the configuration when the part to be cooled is the light source of an optical disk device. There is. In the figure,
1 is a semiconductor laser, 2 is an optical head, 11 is a forced cooling unit,
12 is a first temperature sensor, 13 is a second temperature sensor, 1
4 is a cooling control section. Note that in FIG. 1, illustrations of the optical disk, spindle motor, etc. in FIG. 2 are omitted for simplification of the drawing.

The semiconductor laser 1 is attached to an optical head frame made of metal such as aluminum, and constitutes an optical head 2. In this embodiment, as described above, the entire optical head 2 is the part to be cooled, and the forced cooling part 11 is joined to the optical head 2.

The forced cooling unit 11 is composed of a Peltier cooling module lla joined to the optical head 2 and a radiation fin llb joined to the high temperature side of the Peltier cooling module lla.

Further, a first temperature sensor 12 that detects the ambient temperature in the vicinity of the optical head 2 is arranged, and a second temperature sensor 13 that detects the internal temperature of the optical head is arranged inside the optical head 2. embedded.

The first and second detected temperature values Ta1 and Td2 detected by the first and second temperature sensors 12 and 13 are inputted to the cooling control unit 14 as first and second detection signals D51, D and 2, respectively. Ru.

The cooling control unit 14 has a function of generating a first set temperature value T51 of a predetermined temperature value (20°C in this embodiment), and a function of generating a first set temperature value T51 between the inputted first detected temperature value T,1 and the first set temperature value T51. A function of generating a second set temperature value TS2 according to a comparison result, and a function of generating a second set temperature value Td2 and a second set temperature value T5 that have been input.
1, and applies this drive signal DR to the Peltier cooling module 11a.

Next, based on FIG.
The method of setting the set temperature value will be explained.

In FIG. 3, the horizontal axis represents the ambient temperature near the optical head 2, and the vertical axis represents the first and second detected temperatures and the first and second set temperatures.

Note that the temperature of the optical head 2 is higher than the ambient temperature in the vicinity due to the heat generated by the semiconductor laser 1 and heat conduction from the head actuator (not shown), but in this example, the temperature is always (+)5°C higher. shall be.

As shown in FIG. 3, in this embodiment, the first set temperature value T
．． 1 is set in advance to 20°C, and the cooling control unit 14
When the first detected temperature value T,1 detected by the first temperature sensor 12 exceeds the first set temperature value T5e, the second set temperature value T. 2 is generated and set as follows.

That is, the first detected temperature value Td. is greater than 20°C and less than 35°C, T. 2=25°C Furthermore, when the first detected temperature value Td, is larger than 35°C, a value that satisfies the relationship T=2=Ta++5 15°C is generated.

The cooling control unit 14 also determines that the second detected temperature value Td2 detected by the second temperature sensor 13 embedded inside the optical head 2 is the second set temperature value T. If greater than 2,
T, 2-T. A drive signal (current) D with a magnitude proportional to 2
The second detected temperature value Td2 decreases and the second set temperature value T
The voltage is applied to the Peltier cooling module lla of the forced cooling unit 11 until it becomes equal to m2.

Next, the operation of the above configuration will be explained with reference to the flowchart of FIG.

A first temperature sensor 12 placed near the optical head 2 detects the ambient temperature near the optical head 2, and outputs a first detection signal Ds indicating this detected temperature value (first detected temperature value T, 1).
1, which is input to the cooling control unit 14 (S1
).

On the other hand, the second temperature sensor 13 detects the temperature of the optical head 2 which has become higher than the nearby ambient temperature due to heat generation from the semiconductor laser 1 and heat conduction from the head actuator (not shown).
, and outputs a second detection signal D52 indicating this detected temperature value (second detected temperature value T, 2), which is input to the cooling control unit 14 (S2).

The cooling control unit 14 determines whether the first detected temperature value T,1 based on the manually generated first detection signal D51 exceeds 20° C. (S3). If the cooling control unit 14 determines in step S3 that the first detected temperature value T a 1 exceeds 20°C, then the cooling control unit 14 sets the first detected temperature value Td. Is it over 35℃? A determination is made (S4).

If the cooling control unit 14 determines in step S4 that the first detected temperature value T,1 is 35°C or lower, it sets the second set temperature value T5■ to 25°C (CS5). On the other hand, if it is determined that the first set temperature value T,1 exceeds 35°C, the second set temperature value T5■ is set to the above-mentioned value ('r.2
=T, +5-1 5°C) (S6).

Next, after setting the second set temperature value T52 in step s5 or S6, the cooling control unit 14 controls the input second temperature value T52.
It is determined whether or not the second detected temperature value Td2 based on the detection signal DS2 exceeds the second set temperature value TS2 (S7
).

In step S7, the cooling control unit 14 sets the second detected temperature value Td■ to the second set temperature value TS2 (25°C or T,
;+5-15℃), as mentioned above, a drive signal (current) proportional to (T'a2''r,■) is sent to the Peltier cooling module of the forced cooling section 11. lla (S8). As a result, the Peltier cooling module 11a takes heat from the optical head 2 and carries this heat to the radiation fin llb side.This operation is performed when the second detected temperature value Td2 is the second set temperature value. The process continues until the temperature becomes equal to T.2 (S9), and the optical head 2 reaches the second set temperature value T%.
Forced cooling down to 2.

That is, the optical head 2 has an ambient temperature higher than 20°C;
And, if the temperature is 35℃ or less, the temperature is kept at a constant temperature of 25℃, and
When the ambient temperature is higher than 35°C, the temperature is forcedly cooled to a temperature 15°C lower than that without forced cooling. Note that the reason why the cooling temperature is not constant is to avoid condensation due to excessive cooling.

As explained above, according to this embodiment, the temperature of the light emitting part of the semiconductor laser 1 in a high-speed optical disk device that generates a large amount of heat, or in an optical disk device that performs parallel recording and reproduction using a multi-beam semiconductor laser, when used in a high-temperature environment. There are advantages such as being able to reduce the loss of energy and improve the life of the semiconductor laser 1.

In this embodiment, the entire optical head is the object to be cooled, but various parts can be cooled, such as by adiabatic bonding the semiconductor laser to the optical head frame and using only the semiconductor laser as the object to be cooled. You can choose.

In addition, the optical head has an integrated light source configuration in which everything from the semiconductor laser to the objective lens is mounted on a single optical head frame, but a separate light source type in which the semiconductor laser and objective lens are mounted on separate frames and the objective lens side is moved. It may be.

Furthermore, the forced cooling section is not limited to a Peltier cooling module, such as a liquid cooling module. Furthermore, the first set temperature value is not limited to 20° C., and the method for setting the second set temperature value can be modified in various ways.

(Effect of the invention) As explained below, according to claim (1), the temperature of the object, which increases by -L during use, can be accurately reduced to a predetermined temperature while taking into account the temperature difference with the outside temperature. Can be cooled. Thereby, it is possible to improve the lifespan of parts to be cooled, such as elements used under high temperature conditions.

Therefore, for example, when used in a high-temperature environment or in a high-speed optical disk device that generates a large amount of heat or an optical disk device that performs parallel recording and playback using a multi-beam semiconductor laser, the temperature of the light emitting part of the semiconductor laser can be lowered and the life of the semiconductor laser can be improved. There are advantages such as:

According to claim (2), a first detected temperature value indicating the ambient temperature near the cooling target portion is compared with a first set temperature value set in advance, and the first detected temperature value is determined as the first set temperature value. A second set temperature value is generated when the temperature exceeds the second set temperature value, and this second set temperature value is compared with a second detected temperature value indicating the detected temperature of the cooling target part, and the second detected temperature value is determined as the second set temperature value. If the temperature exceeds the second set temperature value, a drive signal corresponding to the difference between the second detected temperature value and the second set temperature value is sent to the forced cooling unit to forcibly cool the cooling target part to the second set temperature value. Therefore, it is possible to avoid dew condensation due to excessive cooling, and to prevent the adverse effects of dew condensation on the cooling target section.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention, FIG. 2 is a diagram for explaining a cooling method in a conventional disk device,
FIG. 3 is an explanatory diagram of a method for setting the second set temperature value in the cooling control section according to the present invention, and FIG. 4 is a flowchart for explaining the operation of FIG. 1. 1... Semiconductor laser, 2... Optical head, 11...
Forced cooling unit, 12... first temperature sensor, 13...
Second temperature sensor, 14... cooling control section.

Claims (2)

[Claims] (1) A forced cooling unit that cools the part to be cooled by inputting a drive signal, a first temperature sensor that detects the ambient temperature in the vicinity of the part to be cooled, and a second temperature sensor that detects the temperature of the part to be cooled. A temperature sensor, a first detection signal from the first temperature sensor and a second detection signal from the second temperature sensor are input, and the first detection temperature value based on the first detection signal is equal to the first set temperature value. and a cooling control unit that controls the output of the drive signal according to a comparison result between the second detected temperature value based on the second detection signal and the second set temperature value when the temperature exceeds the second temperature value. Forced cooling device. (2) Detecting the ambient temperature near the cooling target part, detecting the temperature of the cooling target part, and setting a first detected temperature value indicating the detected ambient ambient temperature and a first set temperature value set in advance. A second set temperature value is generated when the first detected temperature value exceeds the first set temperature value, and the second set temperature value is compared with a second detected temperature value indicating the detected temperature of the cooling target part. and when the second detected temperature value exceeds the second set temperature value, sends a drive signal to the forced cooling unit according to the difference between the second detected temperature value and the second set temperature value. A forced cooling method, characterized in that the part to be cooled is forcibly cooled to the second set temperature value.