JP2008159111A - Optical disk drive - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical disk drive which can be reduced in cost. <P>SOLUTION: An electric current value calculation section 43 receives a signal SIG 1 from a power controller 41, and acquires a value of a current Iop when a value of optical output reaches a first predetermined value. The electric current value calculation section 43 computes temperature of a semiconductor laser 61 based on an acquired electric current value. Then, in recording information to an optical disk 50, the electric current value calculation section 43 computes an electric current value A based on the temperature of the computed semiconductor laser 61 when a value of optical output of the semiconductor laser 61 reaches a prescribed second value. A laser control circuit 33 can compute temperature of the semiconductor laser based on the temperature characteristic of the semiconductor laser without using a temperature sensing element for detecting the temperature of the semiconductor laser. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an optical disc apparatus for reproducing information from an optical disc and recording information on the optical disc, and more particularly to an optical disc apparatus capable of reducing costs.

  An optical disc apparatus that records information on an optical disc or reproduces information recorded on an optical disc includes an optical pickup. In general, an optical pickup includes a semiconductor laser as a light source.

  In order to record information on an optical disk with high density or accurately record information on an optical disk, it is necessary to always control the power of light output from the semiconductor laser to a desired magnitude. However, the power of the laser beam output from the semiconductor laser varies depending on the temperature in the optical pickup. For this reason, conventionally, a method for controlling a semiconductor laser in accordance with the ambient temperature of the semiconductor laser has been proposed.

  For example, Japanese Patent Laid-Open No. 11-213428 (Patent Document 1) discloses a laser diode drive control device. This drive control device includes a drive circuit for supplying a drive current to the laser diode, storage means for storing temperature-dependent characteristic data of the drive current necessary for obtaining a certain level of light emission output from the laser diode, and surroundings of the laser diode. Temperature detecting means capable of measuring the temperature of The drive control device further reads out the value of the drive current corresponding to the temperature detected by the temperature detection means from the storage means, and controls the drive circuit so that the value of the drive current supplied to the laser diode becomes the value. Control means.

  Japanese Patent Laying-Open No. 2005-32340 (Patent Document 2) discloses an optical pickup capable of optimally controlling the amount of light output from a light source. This optical pickup represents temperature detection means for detecting the temperature of the light source and the wavelength of the light source at the temperature detected by the temperature detection means, and a current applied to the light source to obtain a predetermined light intensity at the detected temperature. Storage means for storing temperature-dependent characteristic data representing.

Japanese Patent Laying-Open No. 2005-353246 (Patent Document 3) discloses an optical pickup capable of performing output adjustment control in a laser light source with high accuracy even when temperature fluctuation occurs in the optical pickup. Disclose. This optical pickup irradiates the optical disk with laser light having a different wavelength according to the type of the optical disk. The optical pickup includes a light receiving element that receives a part of laser light through an optical element, amplification means that amplifies the output of the light receiving element so that the amplification factor varies depending on the wavelength, and the optical element or its surroundings. Temperature deriving means for deriving the temperature of the amplifier, and variable means for varying the amplification factor of the amplifying means based on the temperature derived by the temperature deriving means.
JP-A-11-213428 JP-A-2005-32340 JP 2005-353246 A

  As shown in the above-mentioned documents and the like, according to the prior art, a device for detecting the ambient temperature of the semiconductor laser in order to control the semiconductor laser in accordance with the ambient temperature of the semiconductor laser (for example, a temperature detection element such as a thermistor). Is used. However, it is preferable that the number of parts of the optical disk device is as small as possible from the viewpoint of reducing the manufacturing cost.

  An object of the present invention is to provide an optical disc apparatus capable of reducing the cost.

  In summary, the present invention is an optical disc apparatus, comprising: a semiconductor laser; a drive circuit for supplying a drive current to the semiconductor laser to drive the semiconductor laser; a detection unit for detecting the optical output of the semiconductor laser; A first control unit that determines a first current value of a drive current for controlling the drive circuit in accordance with the detection result to determine the value of the optical output as a predetermined first output value; and information to the optical disc The drive circuit receives the second current value of the drive current for setting the optical output value at the time of recording to a predetermined second output value, and the drive current value becomes the second current value. A second control unit that controls the current value, and a current value calculation unit that calculates the second current value. The current value calculation unit uses the first current value and a predetermined relationship between the temperature of the semiconductor laser and the drive current when the optical output value becomes the predetermined first output value. Calculate the temperature of the laser. The current value calculation unit uses the calculated temperature of the semiconductor laser and a predetermined relationship between the temperature of the semiconductor laser with respect to the driving current when the optical output value becomes the predetermined second output value, A second current value is calculated.

  According to another aspect of the present invention, there is provided an optical disc apparatus, a semiconductor laser, a driving circuit that supplies a driving current to the semiconductor laser to drive the semiconductor laser, a detection unit that detects an optical output of the semiconductor laser, and a detection A first control unit that controls a drive circuit in accordance with a detection result of the unit to determine a first current value of a drive current for setting a light output value to a predetermined first output value; And calculating a temperature of the semiconductor laser using a predetermined relationship between the driving current and the temperature of the semiconductor laser when the optical output value becomes the predetermined first output value. With.

  Preferably, the calculating unit uses the calculated temperature of the semiconductor laser and a predetermined relationship of the temperature of the semiconductor laser with respect to the driving current when the optical output becomes a predetermined second output value. 2 current value is calculated. The optical disc apparatus further includes a second control unit that receives the second current value and controls the drive circuit so that the value of the drive current becomes the second current value.

  More preferably, the predetermined first output value is smaller than the predetermined second output value. The predetermined second output value is a value of the optical output when information is recorded on the optical disc.

  According to the present invention, it is possible to reduce the cost of the optical disc apparatus.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

FIG. 1 is a block diagram showing an optical disc apparatus according to an embodiment of the present invention.
Referring to FIG. 1, an optical disc apparatus 1 includes a CPU 10, a ROM (Read Only Memory) 11, a RAM (Random Access Memory) 12, an operation input unit 13, a display unit 14, and a CODEC (COder DECoder) 21. A signal input / output unit 22, a pickup control circuit 32, a laser control circuit 33, a spindle control circuit 34, a spindle motor 35, and an optical pickup device 60.

  The ROM 11 stores a control program for controlling the optical disc apparatus 1 and data used for controlling the optical disc apparatus 1. The RAM 12 stores data as a work area when the control program is executed. The CPU 10 controls the entire optical disc apparatus 1 by executing a control program stored in the ROM 11 using the RAM 12 as a work area.

  The operation input unit 13 includes operation switches, operation remote controllers, control circuits thereof, and the like. The operation input unit 13 accepts input of operations such as playback, fast forward, rewind, video recording, ejection, reservation information, and the like. The CPU 10 executes a control program corresponding to the signal from the operation input unit 13.

  The display unit 14 includes a display device such as an LCD (Liquid Crystal Display), a control circuit for the display device, and the like, and displays information according to execution of a control program by the CPU 10. The display unit 14 displays, for example, information indicating that playback, fast-forwarding, rewinding, and recording are being performed, reservation information, and the like. The display device is not limited to the LCD, and may be another display device such as an LED (Light Emitting Diode).

  The signal input / output unit 22 includes an input / output terminal, an input / output circuit, and the like. The signal input / output unit 22 receives an input of a video signal or an analog signal of an audio signal from a device that outputs a video signal or an audio signal. And output video signals.

  The CODEC 21 includes an A / D (Analog to Digital) conversion circuit, a D / A (Digital to Analog) conversion circuit, and other peripheral circuits, and is controlled by the CPU 10 to be input to the signal input / output unit 22. Or analog signals of audio signals are converted into digital data of video and audio, or digital data such as video and audio output from the signal input / output unit 22 are converted into analog signals of video signals and audio signals.

  The CODEC 21 not only quantizes an analog signal and converts it into digital data, but also converts the quantized digital data into an analog signal, as well as DV (Digital Video) format and MPEG-2 (Moving Picture Experts). It may have a function of converting into digital data of a predetermined format such as Group phase 2) or converting digital data of a predetermined format into an analog signal.

  When the video and audio input / output by the signal input / output unit 22 is digital data, the CODEC 21 may not be provided, or the digital data input / output by the signal input / output unit 22 instead of the CODEC 21 is predetermined. A conversion circuit having a function of converting digital data of the above format may be provided.

  The spindle motor 35 rotates an optical disc 50 such as a DVD (Digital Versatile Disc) or a CD (Compact Disc). The spindle control circuit 34 controls the spindle motor 35 so that the spindle motor 35 rotates at the number of rotations instructed by the CPU 10.

  The laser control circuit 33 generates a laser beam from the optical pickup device 60 or detects the laser beam in accordance with a control signal from the CPU 10. Further, the laser control circuit 33 outputs a signal corresponding to the detection result of the laser beam to the CPU 10.

  The pickup control circuit 32 performs focusing control, tracking control, lens switching control, and feed control of the optical pickup device 60 in accordance with a control signal calculated based on a signal output from the laser control circuit 33 and a control signal from the CPU 10. To do.

  The optical pickup device 60 is controlled by the laser control circuit 33 to irradiate the track of the optical disc 50 with a reproduction beam, detect the reflected beam, and send a signal corresponding to the reflected beam to the laser control circuit 33 and the RAM 12. Are output to the CODEC 21 via the buffer.

  Further, the optical pickup device 60 irradiates a track of the optical disc 50 with a recording beam corresponding to predetermined data received from the CODEC 21 via the buffer of the RAM 12 and the laser control circuit 33, and the optical disc 50 is subjected to data (information). Record.

  FIG. 2 is a block diagram showing the configuration of the optical pickup device 60 and the laser control circuit 33 of FIG.

  Referring to FIG. 2, optical pickup device 60 includes a semiconductor laser 61, a photodiode 62, a drive circuit 63, and a connector 64. The laser control circuit 33 includes a power control unit 41, a current control unit 42, a current value calculation unit 43, and a connector 44.

  The semiconductor laser 61 emits laser light when supplied with a current Iop from the drive circuit 63. The power of the laser light changes according to the current Iop. On the other hand, when the temperature of the semiconductor laser 61 changes while the current Iop remains the same, the power of the laser light changes according to the temperature.

  The photodiode 62 detects the light output of the semiconductor laser 61. A signal Pm output from the photodiode indicates the power of laser light emitted from the semiconductor laser 61. The drive circuit 63 supplies a current Iop corresponding to the signal SIG 1 from the power control unit 41 or the signal SIG 2 from the current control unit 42 to the semiconductor laser 61.

  The connector 64 is connected to the connector 44. A signal Pm from the photodiode 62 is input to the power control unit 41 via the connectors 64 and 44.

  The power control unit 41 receives the signal Pm and controls the drive circuit 63. Specifically, the power control unit 41 receives the signal Pm, and sets the current value of the current Iop so that the value of the optical output of the semiconductor laser 61 (the value of the power of the laser beam) becomes a predetermined first value. The signal SIG1 shown is changed. The drive circuit 63 changes the current Iop according to the signal SIG1. As a result, the light output value becomes the predetermined first value. The power control unit 41 outputs a signal SIG1 to the current value calculation unit 43 when the value of the optical output reaches a predetermined first value.

  The current control unit 42 outputs a signal SIG2 when information is recorded on the optical disc 50 shown in FIG. Drive circuit 63 outputs current Iop in response to signal SIG2. The current control unit 42 receives the current value A from the current value calculation unit 43 and controls the drive circuit 63 so that the value of the current Iop becomes equal to the current value A. Thus, when information is recorded on the optical disc 50, the power of the laser beam can be set to a size necessary for recording information on the optical disc.

  The current value calculation unit 43 receives the signal SIG1 from the power control unit 41, and acquires the value of the current Iop when the value of the optical output reaches a predetermined first value. The current value calculation unit 43 calculates the temperature of the semiconductor laser 61 based on the acquired current value.

  Next, when recording information on the optical disc 50, the current value calculation unit 43 determines the current when the light output value of the semiconductor laser 61 becomes a predetermined second value based on the calculated temperature of the semiconductor laser 61. Calculate the value. This current value is the current value A described above.

  When reproducing information recorded on the optical disc 50, the current value calculation unit 43 does not output the current value A, and the current control unit 42 outputs the current value stored in advance as the signal SIG2. However, the current value calculation unit 43 may output a constant current value to the current control unit 42 regardless of the temperature, and the current control unit 42 may control the drive circuit 63 based on the current value.

  FIG. 3 is a general diagram showing the relationship between the drive current of the semiconductor laser and the power of light output from the semiconductor laser.

  In FIG. 3, the relationship between the forward current (semiconductor laser drive current) and the optical output power of the semiconductor laser when the temperature of the semiconductor laser is 0 ° C., 25 ° C., 40 ° C., 60 ° C., 70 ° C., and 75 ° C. Is shown.

  As shown in FIG. 3, when the temperature of the semiconductor laser is the same (for example, 25 ° C.), the optical output power of the semiconductor laser increases as the forward current increases. When the forward current is the same (for example, when the forward current is 100 mA), the optical output power decreases as the temperature increases.

  FIG. 3 shows that in order to make the optical output power constant regardless of the temperature fluctuation of the semiconductor laser, it is necessary to change the forward current according to the temperature of the semiconductor laser. In order to calculate the current value A, the current value calculation unit 43 obtains the relationship between the forward current and the optical output power as shown in FIG. 3 based on data stored in advance.

FIG. 4 is a diagram illustrating an example of data stored in the current value calculation unit 43 of FIG.
4 and 2, current value calculation unit 43 stores a current value when the optical output power of semiconductor laser 61 is 10 mW and a current value when the optical output power of semiconductor laser 61 is 60 mW. . The values of 10 mW and 60 mW correspond to the above-mentioned “predetermined first value” and “predetermined second value”, respectively.

  The predetermined first and second values are not limited to these values, and can be determined appropriately. However, the predetermined first value is preferably smaller than the predetermined second value. Thereby, when the power control unit 41 controls the drive circuit 63, the current Iop becomes small, so that the power consumption in the optical pickup device 60 can be reduced as a whole.

  The current value calculation unit 43 stores a current value (75 mA) when the temperature of the semiconductor laser 61 is 25 ° C. and a current value (80 mA) when the temperature of the semiconductor laser 61 is 60 ° C. as the current value when the optical output power is 10 mW. To do. Similarly, the current value calculation unit 43 calculates a current value (120 mA) when the temperature of the semiconductor laser 61 is 25 ° C. and a current value (140 mA) when the temperature of the semiconductor laser 61 is 60 ° C. as the current value when the optical output power is 60 mW. Remember.

  When calculating the temperature of the semiconductor laser 61, the power control unit 41 controls the drive circuit 63 so that the power of light output from the semiconductor laser 61 becomes 10 mW. The current value calculation unit 43 is an equation (linear function) indicating the relationship between temperature and current value when the optical output power is 10 mW from the temperature (25 ° C., 60 ° C.) and current value (75 mA, 80 mA) described above. Ask for. Then, the current value calculation unit 43 calculates the temperature of the semiconductor laser 61 based on this equation and the value of the current Iop determined by the power control unit 41.

  Next, when recording information on the optical disc 50 (FIG. 1), the current value calculation unit 43 calculates a current value A. The current value A at this time is the value of the current Iop for outputting light with a power of 60 mW from the semiconductor laser 61. In this case, the current value calculation unit 43 calculates the relationship between the temperature with respect to the current value when the optical output power is 60 mW from the temperature (25 ° C., 60 ° C.) and the current value (120 mA, 140 mA) (1 Next function). Then, the current value calculation unit 43 calculates a current value A based on this equation and the calculated temperature.

  In the example shown in FIG. 4, the number of current value data (which may be considered temperature data) corresponding to each optical output power is two. Thereby, the calculation load of the current value calculation unit 43 can be reduced. However, the number of data corresponding to each optical output power may be more than two. In this case, the current value calculation unit 43 can calculate the temperature of the semiconductor laser 61 more accurately. Furthermore, the value of the current Iop can be calculated more accurately by calculating the temperature of the semiconductor laser 61 more accurately.

FIG. 5 is a diagram showing a comparative example of the optical disc apparatus according to the present embodiment.
Referring to FIG. 5, optical pickup device 60 includes a semiconductor laser 61, a photodiode 62, a drive circuit 63, a connector 64, a fixed resistor 65, and a thermistor 66. 5 except for the fixed resistor 65 and the thermistor 66 is the same as the corresponding part of the optical pickup device 60 shown in FIG.

  Fixed resistor 65 and thermistor 66 are connected in series between the power supply node and the ground node. One end of the thermistor 66 (the end connected to one end of the fixed resistor 65) is connected to the current value calculation unit 43 via the connectors 64 and 44. In the configuration shown in FIG. 5, the signal value SIG <b> 1 from the power control unit 41 is not input to the current value calculation unit 43.

  The fixed resistor 65 and the thermistor 66 constitute a voltage dividing circuit. When the ambient temperature of the semiconductor laser 61 changes, the resistance value of the thermistor 66 changes. Therefore, the voltage value input to the current value calculation unit 43 also changes according to the ambient temperature of the semiconductor laser 61. The current value calculation unit 43 stores a relationship between the voltage value and the ambient temperature of the semiconductor laser 61 in advance. The current value calculation unit 43 calculates the temperature of the semiconductor laser 61 based on the input voltage value.

  However, according to the configuration shown in FIG. 5, the optical pickup device 60 includes the fixed resistor 65 and the thermistor 66. As a result, in the comparative example, the cost of parts procurement and the cost for mounting the fixed resistor 65 and the thermistor 66 on the circuit board are higher than in the present embodiment.

  Furthermore, since the current value calculation unit 43 receives the output from the voltage dividing circuit composed of the fixed resistor 65 and the thermistor 66, the number of pins of the connector 64 and the connector 44 increases. Generally, as the number of pins of a connector increases, the cost of the connector itself increases and the number of wires connected to the connector increases. For these reasons, the cost of the comparative example tends to be high.

  On the other hand, not only the thermistor 66 but also the semiconductor laser 61 is an element whose characteristics change with temperature. In this embodiment, the semiconductor laser 61 is used not only as a light source but also as a temperature detection element. Thereby, according to this Embodiment, it becomes unnecessary to provide the thermistor 66 (and fixed resistance 65). Therefore, according to the present embodiment, the cost of the optical disc apparatus can be reduced.

  The thermistor is provided around the semiconductor laser 61. Therefore, in the comparative example, the ambient temperature of the semiconductor laser 61 can be measured, but it is difficult to measure the temperature of the semiconductor laser 61 itself. That is, in the comparative example, the temperature of the semiconductor laser can be measured only indirectly. On the other hand, according to the present embodiment, the temperature of the semiconductor laser 61 itself can be obtained.

FIG. 6 is a flowchart for explaining temperature calculation processing performed by the laser control circuit 33.
Referring to FIGS. 6 and 2, first, power control unit 41 sends signal SIG1 to drive circuit 63 based on signal Pm from photodiode 62 to control drive circuit 63 (step S1). The power control unit 41 performs the operation in step S1 until the semiconductor laser 61 emits light with a predetermined power (for example, 10 mW shown in FIG. 4).

  Next, the power control unit 41 determines a current value when the optical output power of the semiconductor laser 61 is a predetermined first value (step S2). The power control unit 41 outputs a signal SIG1 indicating the current value to the current value calculation unit 43.

  Subsequently, the current value calculation unit 43 calculates the temperature of the semiconductor laser 61 based on the current value indicated by the signal SIG1 and a predetermined temperature relationship with respect to the current value of the semiconductor laser (step S3). As described above, the current value calculation unit 43 calculates the relationship of the temperature to the current value when the optical output power is 10 mW from the temperature (25 ° C., 60 ° C.) and the current value (75 mA, 80 mA) shown in FIG. The expression (linear function) shown is obtained. Then, the current value calculation unit 43 calculates the temperature of the semiconductor laser 61 based on this equation and the value of the current Iop determined by the power control unit 41. When the process of step S3 ends, the entire process ends.

  FIG. 7 is a flowchart for explaining the operation of the laser control circuit 33 when information is recorded on the optical disc 50.

  With reference to FIGS. 7 and 2, the current value calculation unit 43 first determines the output power (power of the output light) from the semiconductor laser 61 (step S11). For example, the power of the laser beam output from the semiconductor laser differs between when information is recorded on the optical disk and when information recorded on the optical disk is reproduced. When information is recorded on different types of optical disks, the power of light output from the semiconductor laser 61 may be changed for each type of optical disk. The current value calculation unit 43 determines the power of the laser beam output from the semiconductor laser 61 according to such various conditions.

  Next, the current value calculation unit 43 calculates a current value A based on the temperature calculated in step S3 of FIG. 6 (step S12). In step S12, the current value calculation unit 43 shows the relationship of the temperature to the current value when the optical output power is 60 mW from the temperature (25 ° C., 60 ° C.) and the current value (120 mA, 140 mA) shown in FIG. An expression (linear function) is obtained. Then, the current value calculation unit 43 calculates the current value A based on this equation and the calculated temperature. The current value calculation unit 43 outputs the current value A to the current control unit 42.

  Subsequently, the current control unit 42 controls the drive circuit 63 based on the current value A so that the actual current Iop becomes the current value A calculated in step S12 (step S13). When the process of step S13 ends, the entire process ends.

  Thus, according to the present embodiment, the temperature of the semiconductor laser can be calculated based on the temperature characteristics of the semiconductor laser without using a temperature detection element for detecting the temperature of the semiconductor laser. Therefore, according to the present embodiment, the temperature detecting element for detecting the temperature of the semiconductor laser can be eliminated, and the cost of the optical disc apparatus can be reduced.

  Further, according to the present embodiment, the temperature of the semiconductor laser itself is calculated, so that the temperature of the semiconductor laser can be obtained more accurately.

  Furthermore, according to the present embodiment, since the current value calculation unit 43 predetermines the value of the current Iop (current value A) at the time of recording on the optical disk, light of a desired power is applied to the optical disk from the start of recording on the optical disk. Can be irradiated. As a result, information such as video and audio can be recorded on the optical disc with high quality.

  For example, the laser control circuit 33 shown in FIG. 2 includes a power control unit 41 for controlling the power of laser light output from the semiconductor laser to be constant. Such a power control unit is generally used for controlling a semiconductor laser. However, the power control unit controls the power of the laser beam in accordance with a signal from a detection circuit that detects the optical output of the semiconductor laser, such as a photodiode. For this reason, it takes a certain amount of time from the start of light emission of the semiconductor laser until the power of the laser light becomes constant.

  When it takes time until the power of the laser beam is stabilized, there is a possibility that the quality of information recorded on the optical disk immediately after the recording on the optical disk starts. However, according to the present embodiment, such a possibility can be reduced.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1 is a block diagram showing an optical disc apparatus according to an embodiment of the present invention. FIG. 2 is a block diagram illustrating configurations of the optical pickup device 60 and the laser control circuit 33 in FIG. 1. It is a general view showing the relationship between the drive current of the semiconductor laser and the power of light output from the semiconductor laser. It is a figure which shows an example of the data memorize | stored in the electric current value calculation part 43 of FIG. It is a figure which shows the comparative example of the optical disk apparatus of this Embodiment. 4 is a flowchart for explaining a temperature calculation process performed by a laser control circuit 33. 4 is a flowchart for explaining the operation of a laser control circuit 33 when information is recorded on an optical disc 50.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Optical disk apparatus, 13 Operation input part, 14 Display part, 22 Signal input / output part, 32 Pickup control circuit, 33 Laser control circuit, 34 Spindle control circuit, 35 Spindle motor, 41 Power control part, 42 Current control part, 43 Current Value calculation unit, 44, 64 connector, 50 optical disc, 60 optical pickup device, 61 semiconductor laser, 62 photodiode, 63 drive circuit, 65 fixed resistor, 66 thermistor.

Claims (4)

An optical disk device,
A semiconductor laser;
A drive circuit for driving the semiconductor laser by supplying a drive current to the semiconductor laser;
A detector for detecting the optical output of the semiconductor laser;
First control for determining the first current value of the drive current for controlling the drive circuit according to the detection result of the detection unit to determine the value of the optical output as a predetermined first output value. And
In response to the second current value of the drive current for setting the optical output value at the time of recording information on the optical disc to a predetermined second output value, the value of the drive current is the second value. A second control unit that controls the drive circuit to have a current value;
A current value calculation unit for calculating the second current value,
The current value calculation unit is configured to determine a relationship between the first current value and a predetermined temperature of the semiconductor laser with respect to the driving current when the optical output value is the predetermined first output value. And calculating the temperature of the semiconductor laser, and the driving current when the calculated temperature of the semiconductor laser and the predetermined optical output value become the predetermined second output value. An optical disk device that calculates the second current value using a relationship between the temperature of the semiconductor laser and the temperature of the semiconductor laser. An optical disk device,
A semiconductor laser;
A drive circuit for driving the semiconductor laser by supplying a drive current to the semiconductor laser;
A detector for detecting the optical output of the semiconductor laser;
First control for determining the first current value of the drive current for controlling the drive circuit according to the detection result of the detection unit to determine the value of the optical output as a predetermined first output value. And
Using the first current value and a predetermined relationship between the temperature of the semiconductor laser and the driving current when the optical output value becomes the predetermined first output value, the semiconductor An optical disc apparatus comprising: a calculation unit that calculates a laser temperature. The calculation unit uses the calculated temperature of the semiconductor laser and a predetermined relationship of the temperature of the semiconductor laser with respect to the driving current when the optical output becomes a predetermined second output value. , Calculate the second current value,
The optical disc apparatus is
The optical disc device according to claim 2, further comprising a second control unit that receives the second current value and controls the drive circuit so that the value of the drive current becomes the second current value. The predetermined first output value is smaller than the predetermined second output value;
The optical disc apparatus according to claim 3, wherein the predetermined second output value is a value of the optical output when information is recorded on the optical disc.

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