US20050053107A1 - Laser power control apparatus - Google Patents
Laser power control apparatus Download PDFInfo
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- US20050053107A1 US20050053107A1 US10/886,589 US88658904A US2005053107A1 US 20050053107 A1 US20050053107 A1 US 20050053107A1 US 88658904 A US88658904 A US 88658904A US 2005053107 A1 US2005053107 A1 US 2005053107A1
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- Prior art keywords
- laser light
- power control
- laser
- laser power
- control apparatus
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/12—Heads, e.g. forming of the optical beam spot or modulation of the optical beam
- G11B7/125—Optical beam sources therefor, e.g. laser control circuitry specially adapted for optical storage devices; Modulators, e.g. means for controlling the size or intensity of optical spots or optical traces
- G11B7/127—Lasers; Multiple laser arrays
- G11B7/1275—Two or more lasers having different wavelengths
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/004—Recording, reproducing or erasing methods; Read, write or erase circuits therefor
- G11B7/0045—Recording
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/12—Heads, e.g. forming of the optical beam spot or modulation of the optical beam
- G11B7/125—Optical beam sources therefor, e.g. laser control circuitry specially adapted for optical storage devices; Modulators, e.g. means for controlling the size or intensity of optical spots or optical traces
- G11B7/126—Circuits, methods or arrangements for laser control or stabilisation
- G11B7/1263—Power control during transducing, e.g. by monitoring
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B2007/0003—Recording, reproducing or erasing systems characterised by the structure or type of the carrier
- G11B2007/0006—Recording, reproducing or erasing systems characterised by the structure or type of the carrier adapted for scanning different types of carrier, e.g. CD & DVD
Definitions
- the present invention relates to a laser power control apparatus for controlling laser power in a combination drive which records information or reads recorded information on/from different types of optical disks by applying different laser lights onto the optical disks. More particularly, the present invention relates to a laser power control apparatus for controlling the laser power such that the different laser lights are collected by a common photodetector.
- the combination drive may be generally represented by one that records and reproduces information on CDs and reproduces information on DVDs, as suggested in Japanese Patent Laid-Open Publication No. 2001-236726, for example.
- two lasers of different powers, a CD laser and a DVD laser need to be controlled individually.
- the front monitor 8 is composed of a photodetector.
- the front monitor 8 collects the CD laser light Lc and generates a laser intensity signal PD 01 having a voltage which is based on the amount of the light collected.
- the offset adjuster 1 adds a potential which corresponds to a predetermined offset value to the laser intensity signal PD 01 through the adder 20 , thereby generating an offset corrected laser intensity signal S 1 .
- the combination drive capable of reproducing or recording information on plural types of optical disks
- only one photodetector is provided which collects laser light to control the power of the laser light, thereby making it possible to produce a compact laser power control apparatus.
- FIG. 3 is a block diagram illustrating a configuration of a laser power control apparatus according to a third embodiment of the present invention.
- FIG. 4 is a block diagram illustrating a configuration of a laser power control apparatus according to a fourth embodiment of the present invention.
- FIG. 5 is a block diagram illustrating a configuration of a laser power control apparatus according to a fifth embodiment of the present invention.
- FIG. 6 is a block diagram illustrating a configuration of a laser power control apparatus according to a sixth embodiment of the present invention.
- FIG. 9 is a block diagram illustrating a configuration of a laser power control apparatus according to a ninth embodiment of the present invention.
- FIG. 12 is a block diagram illustrating a configuration of a laser power control apparatus according to a twelfth embodiment of the present invention.
- FIG. 13 is a block diagram illustrating a configuration of a laser power control apparatus according to a thirteenth embodiment of the present invention.
- FIG. 14 is a block diagram illustrating a configuration of a laser power control apparatus according to a fourteenth embodiment of the present invention.
- a laser power control apparatus LPC 1 has a configuration such that in the conventional laser power control apparatus LP, shown in FIG. 17 , the back monitor 19 of the DVD laser power control system LPdvd is eliminated, and the CD laser power control system LPcd and the DVD laser power control system LPdvd are connected to each other at a junction 11 .
- the controller 100 is replaced with a controller 100 a.
- the laser intensity signal PD 0 is generated from one front monitor 8 , the laser intensity signal PD 0 is essentially the same as the aforementioned laser intensity signals PD 01 and PD 02 .
- a reproduction amplification unit Up and a recording amplification unit Ur are collectively referred to as an “amplification unit U” and the following description also collectively refers them as the “amplification unit U”, as is the case above.
- the controller 10 a detects whether to use a DVD drive or a CD drive based on an operation mode signal Sm inputted from a combination drive (not shown), and generates a control signal Sca for controlling each component of the laser power control apparatus LPC 1 , in accordance with the drive to be used.
- a control signal Sca for controlling each component of the laser power control apparatus LPC 1 , in accordance with the drive to be used.
- an operational amplifier 6 of the DVD laser power control unit LPdvd_ 1 is turned off so that a laser diode LD 2 will not emit light. More specifically, the output of the operational amplifier 6 is pulled up to the power supply voltage. Accordingly, only the CD laser power control system LPcd (CD laser power control unit LPcd_ 1 ) functions and thus the laser power of the laser diode LD 1 is appropriately controlled.
- the laser power of only the drive to be used is appropriately controlled based on the operation mode (i.e., an operation mode signal Sm) of the combination drive.
- a laser power control apparatus LPC 2 is a modified version of the laser power control apparatus LPC 1 shown in FIG. 1 , in which the laser power control unit LPdvd_ 1 is replaced with a DVD laser power control unit LPdvd_ 2 and the controller 100 a is replaced with a controller 100 b .
- the DVD laser power control unit LPdvd_ 2 is different from the DVD laser power control unit LPdvd_ 1 in that a variable gain circuit 9 (referred to as “VGA” in the drawing) is inserted between an operational amplifier 6 and a junction 11 .
- VGA variable gain circuit 9
- a laser intensity signal PD 02 (PD 0 ) is gain adjusted by the variable gain circuit 9 and then inputted to the operational amplifier 6 . That is, in order to allow a front monitor 8 , which is essentially used to detect CD laser light Lc, to detect DVD laser light Ld having different intensity characteristics, etc., from the CD laser light Lc, it is necessary to change the sensitivity (voltage gain) of the variable gain circuit 9 to the DVD laser light Ld. In terms of this, in the present embodiment, the necessity of changing the power supply gain of the front monitor 8 itself is eliminated by gain adjusting the laser intensity signal PD 0 by the variable gain circuit 9 . In other words, the front monitor 8 which is used for CD laser light Lc can also be used for DVD laser light Ld having a higher energy, with appropriate sensitivity, without the need to adjust the front monitor 8 itself.
- the controller 100 b turns off the offset adjuster 1 , variable gain circuit 2 , sample/hold circuit 3 , and operational amplifier 4 of the CD laser power control unit LPcd_ 1 . Accordingly, only the DVD laser power control unit LPdvd_ 2 functions and thus the laser power of the laser diode LD 2 is appropriately controlled.
- the controller 100 d generates a control signal Scd based on an operation mode signal Sm and controls the laser power control apparatus LPC 4 .
- the operational amplifier 6 and variable gain circuit 9 of the DVD laser power control unit LPdvd_ 4 are turned off so that a laser diode LD 2 will not emit light. Accordingly, only the CD laser power control unit LPcd_ 1 functions and thus the laser power of a laser diode LD 1 is appropriately controlled.
- a laser power control apparatus LPC 5 is a modified version of the laser power control apparatus LPC 1 shown in FIG. 1 , in which the laser power control unit LPdvd_ 1 is replaced with a DVD laser power control unit LPdvd_ 5 and the controller 10 a is replaced with a controller 10 e .
- an operational amplifier 6 is connected between the adder 20 and amplification unit U of the CD laser power control unit LPcd_ 1 through a junction 12 instead of the junction 11 .
- the controller 100 e generates a control signal Sce based on an operation mode signal Sm and controls the laser power control apparatus LPC 5 .
- the operational amplifier 6 of the DVD laser power control unit LPdvd_ 5 is turned off so that a laser diode LD 2 will not emit light. Accordingly, only the CD laser power control unit LPcd_ 1 functions and thus the laser power of the laser diode LD 1 is appropriately controlled.
- a laser power control apparatus LPC 6 is a modified version of the laser power control apparatus LPC 5 shown in FIG. 5 , in which the laser power control unit LPdvd_ 5 is replaced with a DVD laser power control unit LPdvd_ 6 and the controller 100 e is replaced with a controller 100 f .
- a variable gain circuit 9 is additionally provided between an operational amplifier 6 and a junction 12 .
- a laser intensity signal PD 0 (PD 01 ) outputted from the variable gain circuit 9 is offset adjusted by an adder 20 and an offset adjuster 1 , then further gain adjusted by the variable gain circuit 9 , and then inputted to the operational amplifier 6 .
- This configuration provides the same advantageous effect as that obtained by the laser power control apparatus LPC 3 shown in FIG. 3 .
- the laser power control apparatus LPC 6 can be reduced in circuit size compared to the laser power control apparatus LPC 3 .
- the controller 100 f generates a control signal Scf based on an operation mode signal Sm and controls the laser power control apparatus LPC 6 .
- the operational amplifier 6 and variable gain circuit 9 of the DVD laser power control unit LPdvd_ 6 are turned off so that a laser diode LD 2 will not emit light. Accordingly, only the CD laser power control unit LPcd_ 1 functions and thus the laser power of a laser diode LD 1 is appropriately controlled.
- the controller 100 f turns off the variable gain circuit 2 , sample/hold circuit 3 , and operational amplifier 4 of the CD laser power control unit LPcd_ 1 .
- the offset value of the offset adjuster 1 is changed to a value appropriate for the laser diode LD 2 .
- the variable gain circuits 2 and 9 have fixed gain values.
- the controller 100 g generates a control signal Scg based on an operation mode signal Sm and controls the laser power control apparatus LPC 7 .
- the operational amplifier 6 and variable gain circuit 9 of the DVD laser power control unit LPdvd_ 7 are turned off so that a laser diode LD 2 will not emit light. Accordingly, only the CD laser power control unit LPcd_ 1 functions and thus the laser power of a laser diode LD 1 is appropriately controlled.
- the controller 100 g turns off the variable gain circuit 2 , sample/hold circuit 3 , and operational amplifier 4 of the CD laser power control unit LPcd_ 1 .
- the offset value of an offset adjuster 1 is changed to a value appropriate for the laser diode LD 2 .
- the variable gain circuits 2 and 9 have fixed gain values.
- the voltage values of the variable voltage sources 5 and 25 are fixed to predetermined values.
- a laser power control apparatus LPC 9 is a modified version of the laser power control apparatus LPC 8 shown in FIG. 8 , in which the laser power control unit LPdvd_ 8 is replaced with a DVD laser power control unit LPdvd_ 9 and the controller 100 h is replaced with a controller 100 i .
- the reference potential PD 2 ref of the operational amplifier 6 is replaced with a variable voltage source 25 .
- the controller 100 j generates a control signal Scj based on an operation mode signal Sm and controls the laser power control apparatus LPC 10 .
- the operational amplifier 6 of the DVD laser power control unit LPdvd_ 10 is turned off so that a laser diode LD 2 will not emit light. Accordingly, only the CD laser power control unit LPcd_ 1 functions and thus the laser power of a laser diode LD 1 is appropriately controlled.
- the controller 100 l turns off a laser drive circuit 7 of the CD laser power control unit LPcd_ 1 , while allowing a sample/hold circuit 3 to operate at all times.
- the offset value of an offset adjuster 1 and the gain value of the variable gain circuit 2 are changed to values appropriate for the laser diodes LD 1 and LD 2 .
- the values of a variable voltage source 5 and the variable gain circuit 2 are fixed to predetermined values.
- the polarity reverser 16 has the function of reversing the polarity of a signal to be inputted, in response to an instruction from the controller 100 m , and outputting the signal. Specifically, a laser intensity signal PD 0 (PD 01 ) outputted from the front monitor 8 undergoes a polarity reversal, if necessary, and then is inputted to the CD laser power control unit LPcd_ 13 .
- the polarity of a laser intensity signal PD 0 (PD 01 ) is reversed by the polarity reverser 16 , depending on the diode to be driven (i.e., either the laser diode LD 1 or the laser diode LD 2 ).
- a laser power control apparatus according to the present embodiment will be described.
- the configuration of a laser power control apparatus LPC 15 is the same as that of the laser power control apparatus LPC 14 shown in FIG. 14 , except that the controller 100 n is replaced with a controller 100 o.
- a polarity-reversible operational amplifier 4 ′ includes therein a switch SW 1 and a switch SW 2 .
- the output polarity can be reversed.
- the controller 100 q turns off the variable gain circuit 2 , the sample/hold circuit 32 , the operational amplifier 41 , and the operational amplifier 42 . Then, when the laser diode LD 1 or LD 2 emits light, the controller 100 q changes the offset value of the offset adjuster 1 .
- the sample/hold circuit 31 is allowed to operate at all times.
- the controller 100 q turns off the offset adjuster 1 , the variable gain circuit 2 , the sample/hold circuit 31 , the sample/hold circuit 32 , the operational amplifier 41 , and the operational amplifier 42 .
- the controller 100 q turns off the offset adjuster 1 , the variable gain circuit 2 , the sample/hold circuit 31 , the sample/hold circuit 32 , and the operational amplifier 41 , and the operational amplifier 42 .
- This configuration allows the controller to select from a plurality of characteristics depending on the situation, whereby flexibility is increased. Further, since the back monitor can be used, it is also possible to control a laser power in a conventional system. Therefore, this configuration can be applied to combination drives where a reduction in size is sought.
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- Optics & Photonics (AREA)
- Semiconductor Lasers (AREA)
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- Optical Recording Or Reproduction (AREA)
Abstract
In a laser power control apparatus for controlling a laser power of a combination drive, first laser light Lc applied onto a first optical disk and second laser light Ld applied onto a second optical disk is collected by one photodetector 8.
Description
- 1. Field of the Invention
- The present invention relates to a laser power control apparatus for controlling laser power in a combination drive which records information or reads recorded information on/from different types of optical disks by applying different laser lights onto the optical disks. More particularly, the present invention relates to a laser power control apparatus for controlling the laser power such that the different laser lights are collected by a common photodetector.
- 2. Description of the Background Art
- In recent years, combination drives which are capable of reading recorded information or writing information using plural types of optical disks have been widely used. The combination drive may be generally represented by one that records and reproduces information on CDs and reproduces information on DVDs, as suggested in Japanese Patent Laid-Open Publication No. 2001-236726, for example. In such a combination drive, two lasers of different powers, a CD laser and a DVD laser, need to be controlled individually.
- Referring to
FIG. 17 , a laser power control apparatus in a conventional combination drive will be described. A laser power control apparatus LP includes a CD laser power control system LPcd for controlling the power of a CD laser; a DVD laser power control system LPdvd for controlling the power of a DVD laser; and acontroller 100 for controlling the operation of the entire laser power control apparatus LP. - The CD laser power control system LPcd includes an offset adjuster 1 (referred to as “Offset” in the drawing), an
adder 20, a reproduction amplification unit Up, a recording amplification unit Ur, a laser drive circuit 7 (referred to as “LDD” in the drawing), a laser diode LD1, and a front monitor 8 (referred to as “PD” in the drawing). Thelaser drive circuit 7 allows the laser diode LD1 to emit CD laser light Lc having a predetermined amount of light, based on a reproduction laser drive control signal LDI1 supplied from the reproduction amplification unit Up or on a recording laser drive control signal LDI3 supplied from the recording amplification unit Ur. - The
front monitor 8 is composed of a photodetector. Thefront monitor 8 collects the CD laser light Lc and generates a laser intensity signal PD01 having a voltage which is based on the amount of the light collected. Theoffset adjuster 1 adds a potential which corresponds to a predetermined offset value to the laser intensity signal PD01 through theadder 20, thereby generating an offset corrected laser intensity signal S1. - The reproduction amplification unit Up has a
variable gain circuit 2 p (referred to as “VGA” in the drawing), a sample/hold circuit 3 p (referred to as “S/H” in the drawing), and anoperational amplifier 4 p. Thevariable gain circuit 2 p functions so that the laser intensity signal S1 has a sufficient amplitude at reproduction, thereby generating a laser intensity signal S2 p. The sample/holdcircuit 3 p samples and holds the laser intensity signal S2 p at a predetermined timing, thereby generating a laser intensity signal S3 p. Theoperational amplifier 4 p compares between a reference potential Vp supplied from avariable voltage source 5 p and the laser intensity signal S3 p and then generates a reproduction laser drive control signal LDI1 based on the difference obtained from the comparison. - The recording amplification unit Ur has a
variable gain circuit 2 r, a sample/hold circuit 3 r, anoperational amplifier 4 r, and avariable voltage source 5 r, as does the reproduction amplification unit Up. Thevariable gain circuit 2 r functions so that the laser intensity signal S1 has a sufficient amplitude at recording, thereby generating a laser intensity signal S2 r. The sample/holdcircuit 3 r samples and holds the laser intensity signal S2 r at a predetermined timing, thereby generating a laser intensity signal S3 r. Theoperational amplifier 4 r compares between a reference potential Vr supplied from avariable voltage source 5 r and the laser intensity signal S3 r and then generates a recording laser drive control signal LDI3 based on the difference obtained from the comparison. - Note that the reproduction amplification unit Up and the recording amplification unit Ur have basically the same configuration and function except that the reproduction laser drive control signal LDI1 and the recording laser drive control signal LDI3 generated by the reproduction amplification unit Up and the recording amplification unit Ur, respectively, have different levels. Therefore, the reproduction amplification unit Up and the recording amplification unit Ur are hereinafter collectively referred to as an “amplification unit U” as long as there is no particular problem. In addition, the
variable gain circuits variable gain circuit 2”, the sample/hold circuits hold circuit 3”, theoperational amplifiers operational amplifier 4”, and thevariable voltage sources variable voltage source 5”. The reproduction laser drive control signal LDI1 and the recording laser drive control signal LDI3 are hereinafter collectively referred to as a “CD laser drive control signal LDIc”. - The DVD laser power control system LPdvd has an
operational amplifier 6, a transistor PNP, a laser diode LD2, and a back monitor 19 (referred to as “PD” in the drawing). The transistor PNP allows the laser diode LD2 to emit DVD laser light Ld having a predetermined amount of light, based on a reproduction laser drive control signal LDI2 supplied from theoperational amplifier 6. Theback monitor 19 is composed of a photodetector, as is thefront monitor 8. Theback monitor 19 collects the DVD laser light Ld and generates a laser intensity signal PD02 having a voltage which is based on the amount of the light collected. Theoperational amplifier 6 compares the laser intensity signal PD02 to a reference signal PD2 ref and then generates a reproduction laser drive control signal LDI2 based on the difference obtained from the comparison. - To the
controller 100 a feedback signal Sf which indicates the operational conditions of the components of the laser power control apparatus LP is inputted from the laser power control apparatus LP. Further, to thecontroller 100 an operation mode signal Sm which indicates a user's instruction is inputted from the combination drive. Thecontroller 100 generates a control signal Sc for controlling the operation of each component of the laser power control apparatus LP, based on the operation mode signal Sm and the feedback signal Sf. - As described above, in the conventional combination drive, the CD laser power control system LPcd and the DVD laser power control system LPdvd are independently configured, and thus a space-consuming photodetector is redundantly provided on each of the font and back monitors, which inhibits production of a small size combination drive.
- Therefore, an object of the present invention is to provide a small size laser power control apparatus obtained by providing commonality of redundantly provided front and back monitors. The present invention has the following features to attain the object mentioned above.
- A first aspect of the present invention is directed to a laser power control apparatus for controlling an output of laser light which is exclusively applied onto a first optical disk and a second optical disk in a combination drive to record or read information thereon or therefrom, the apparatus comprising: a first laser light generator for generating first laser light to be applied onto the first optical disk; a first drive current generator for generating a drive current of the first laser light generator; a second laser light generator for generating second laser light to be applied onto the second optical disk; a second drive current generator for generating a drive current of the second laser light generator; a laser light intensity detector for exclusively collecting the first laser light and the second laser light and generating a first laser light intensity signal which indicates an intensity of the collected laser light; a first laser light generating current controller for controlling the first laser light generator based on the first laser light intensity signal; and a second laser light generating current controller for controlling the second laser light generator based on the first laser light intensity signal.
- As described above, in the present invention, in the combination drive capable of reproducing or recording information on plural types of optical disks, only one photodetector is provided which collects laser light to control the power of the laser light, thereby making it possible to produce a compact laser power control apparatus.
- These and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.
-
FIG. 1 is a block diagram illustrating a configuration of a laser power control apparatus according to a first embodiment of the present invention; -
FIG. 2 is a block diagram illustrating a configuration of a laser power control apparatus according to a second embodiment of the present invention; -
FIG. 3 is a block diagram illustrating a configuration of a laser power control apparatus according to a third embodiment of the present invention; -
FIG. 4 is a block diagram illustrating a configuration of a laser power control apparatus according to a fourth embodiment of the present invention; -
FIG. 5 is a block diagram illustrating a configuration of a laser power control apparatus according to a fifth embodiment of the present invention; -
FIG. 6 is a block diagram illustrating a configuration of a laser power control apparatus according to a sixth embodiment of the present invention; -
FIG. 7 is a block diagram illustrating a configuration of a laser power control apparatus according to a seventh embodiment of the present invention; -
FIG. 8 is a block diagram illustrating a configuration of a laser power control apparatus according to an eighth embodiment of the present invention; -
FIG. 9 is a block diagram illustrating a configuration of a laser power control apparatus according to a ninth embodiment of the present invention; -
FIG. 10 is a block diagram illustrating a configuration of a laser power control apparatus according to a tenth embodiment of the present invention; -
FIG. 11 is a block diagram illustrating a configuration of a laser power control apparatus according to an eleventh embodiment of the present invention; -
FIG. 12 is a block diagram illustrating a configuration of a laser power control apparatus according to a twelfth embodiment of the present invention; -
FIG. 13 is a block diagram illustrating a configuration of a laser power control apparatus according to a thirteenth embodiment of the present invention; -
FIG. 14 is a block diagram illustrating a configuration of a laser power control apparatus according to a fourteenth embodiment of the present invention; -
FIG. 15 is a block diagram illustrating a configuration of a laser power control apparatus according to a fifteenth embodiment of the present invention; -
FIG. 16 is a block diagram illustrating a configuration of a laser power control apparatus according to a sixteenth embodiment of the present invention; and -
FIG. 17 is a block diagram illustrating a configuration of a laser power control apparatus used in a conventional combination drive. - (First Embodiment)
- Referring to
FIG. 1 , a laser power control apparatus according to a first embodiment of the present invention will be described. Put simply, a laser power control apparatus LPC1 has a configuration such that in the conventional laser power control apparatus LP, shown inFIG. 17 , the back monitor 19 of the DVD laser power control system LPdvd is eliminated, and the CD laser power control system LPcd and the DVD laser power control system LPdvd are connected to each other at ajunction 11. In addition, thecontroller 100 is replaced with acontroller 100 a. - Specifically, in the laser power control apparatus LPC1, a DVD laser power control unit LPdvd_1 configured by eliminating the back monitor 19 from the DVD laser power control system LPdvd, and a CD laser power control unit LPcd_1 configured by eliminating the
front monitor 8 from the CD laser power control system LPcd, share afront monitor 8. Thefront monitor 8 collects either CD laser light Lc or DVD laser light Ld and generates a laser intensity signal PD0. The laser intensity signal PD0 is then supplied to the CD laser power control unit LPcd_1 and the DVD laser power control unit LPdvd_1 through thejunction 11. - Note that although the laser intensity signal PD0 is generated from one
front monitor 8, the laser intensity signal PD0 is essentially the same as the aforementioned laser intensity signals PD01 and PD02. Note also that inFIG. 1 , due to space limitations, a reproduction amplification unit Up and a recording amplification unit Ur are collectively referred to as an “amplification unit U” and the following description also collectively refers them as the “amplification unit U”, as is the case above. - Now, the operation of the
controller 100 a will be described. The controller 10 a detects whether to use a DVD drive or a CD drive based on an operation mode signal Sm inputted from a combination drive (not shown), and generates a control signal Sca for controlling each component of the laser power control apparatus LPC1, in accordance with the drive to be used. Specifically, in the case where the CD drive is used, i.e, in the case where a laser diode LD1 emits light, anoperational amplifier 6 of the DVD laser power control unit LPdvd_1 is turned off so that a laser diode LD2 will not emit light. More specifically, the output of theoperational amplifier 6 is pulled up to the power supply voltage. Accordingly, only the CD laser power control system LPcd (CD laser power control unit LPcd_1) functions and thus the laser power of the laser diode LD1 is appropriately controlled. - On the other hand, in the case where the DVD drive is used, i.e., in the case where the laser diode LD2 emits light, an offset
adjuster 1, avariable gain circuit 2 p, a sample/hold circuit 3 p, and anoperational amplifier 4 p of the CD laser power control unit LPcd_1 are turned off. Accordingly, only the DVD laser power control system LPdvd (DVD laser power control unit LPdvd_1) functions and thus the laser power of the laser diode LD2 is appropriately controlled. - As described above, in the present embodiment, while a laser intensify signal PD0 outputted from the
front monitor 8 is supplied through thejunction 11 to both the CD laser power control system LPcd and the DVD laser power control system LPdvd, the laser power of only the drive to be used is appropriately controlled based on the operation mode (i.e., an operation mode signal Sm) of the combination drive. - (Second Embodiment)
- Referring to
FIG. 2 , a laser power control apparatus according to the present embodiment will be described. A laser power control apparatus LPC2 is a modified version of the laser power control apparatus LPC1 shown inFIG. 1 , in which the laser power control unit LPdvd_1 is replaced with a DVD laser power control unit LPdvd_2 and thecontroller 100 a is replaced with acontroller 100 b. The DVD laser power control unit LPdvd_2 is different from the DVD laser power control unit LPdvd_1 in that a variable gain circuit 9 (referred to as “VGA” in the drawing) is inserted between anoperational amplifier 6 and ajunction 11. - A laser intensity signal PD02 (PD0) is gain adjusted by the
variable gain circuit 9 and then inputted to theoperational amplifier 6. That is, in order to allow afront monitor 8, which is essentially used to detect CD laser light Lc, to detect DVD laser light Ld having different intensity characteristics, etc., from the CD laser light Lc, it is necessary to change the sensitivity (voltage gain) of thevariable gain circuit 9 to the DVD laser light Ld. In terms of this, in the present embodiment, the necessity of changing the power supply gain of thefront monitor 8 itself is eliminated by gain adjusting the laser intensity signal PD0 by thevariable gain circuit 9. In other words, thefront monitor 8 which is used for CD laser light Lc can also be used for DVD laser light Ld having a higher energy, with appropriate sensitivity, without the need to adjust thefront monitor 8 itself. - Now the operation of the
controller 100 b will be described. As is the case with the controller 10 a, thecontroller 100 b also generates a control signal Scb based on an operation mode signal Sm and controls the laser power control apparatus LPC2. In the case where the CD drive is used, i.e., in the case where a laser diode LD1 emits light, theoperational amplifier 6 andvariable gain circuit 9 of the DVD laser power control unit LPdvd_2 are turned off so that a laser diode LD2 will not emit light. Accordingly, only the CD laser power control unit LPcd_1 functions and thus the laser power of the laser diode LD1 is appropriately controlled. - On the other hand, in the case where the DVD drive is used, i.e., in the case where the laser diode LD2 emits light, the
controller 100 b turns off the offsetadjuster 1,variable gain circuit 2, sample/hold circuit 3, andoperational amplifier 4 of the CD laser power control unit LPcd_1. Accordingly, only the DVD laser power control unit LPdvd_2 functions and thus the laser power of the laser diode LD2 is appropriately controlled. - (Third Embodiment)
- Referring to
FIG. 3 , a laser power control apparatus according to the present embodiment will be described. A laser power control apparatus LPC3 is a modified version of the laser power control apparatus LPC2 shown inFIG. 2 , in which the laser power control unit LPdvd_2 is replaced with a DVD laser power control unit LPdvd_3 and thecontroller 100 b is replaced with acontroller 100 c. The DVD laser power control unit LPdvd_3 is different from the DVD laser power control unit LPdvd_2 in that an offsetadjuster 18 is additionally provided between avariable gain circuit 9 and ajunction 11 through anadder 22. - By using the offset
adjuster 18, the sensitivity to DVD laser light Ld applied from a laser diode LD2 can be more accurately adjusted than the laser power control apparatus LPC2, without the need to change the voltage gain of afront monitor 8. - Next, the operation of the
controller 100 c will be described. Thecontroller 100 c generates a control signal Scc based on an operation mode signal Sm and controls the laser power control apparatus LPC3. In the case where the CD drive is used, i.e., in the case where a laser diode LD1 emits light, theoperational amplifier 6,variable gain circuit 9, and offsetadjuster 18 of the DVD laser power control unit LPdvd_3 are turned off so that the laser diode LD2 will not emit light. Accordingly, only the CD laser power control unit LPcd_1 functions and thus the laser power of the laser diode LD1 is appropriately controlled. - On the other hand, in the case where the DVD drive is used, i.e., in the case where the laser diode LD2 emits light, the
controller 100 c turns off the offsetadjuster 1,variable gain circuit 2, sample/hold circuit 3, andoperational amplifier 4 of the CD laser power control unit LPcd_1. Accordingly, only the DVD laser power control unit LPdvd_3 functions and thus the laser power of the laser diode LD2 is appropriately controlled. - (Fourth Embodiment)
- Referring to
FIG. 4 , a laser power control apparatus according to the present embodiment will be described. A laser power control apparatus LPC4 is a modified version of the laser power control apparatus LPC2 shown inFIG. 2 , in which the laser power control unit LPdvd_2 is replaced with a DVD laser power control unit LPdvd_4 and thecontroller 100 b is replaced with acontroller 100 d. In the DVD laser power control unit LPdvd_4, instead of the reference potential PD2 ref, avariable voltage source 25 is connected to anoperational amplifier 6. By using thevariable voltage source 25, a given voltage within a predetermined range can be set as a reference potential, and therefore the sensitivity to DVD laser light Ld can be more accurately adjusted than the laser power control apparatus LPC2. - Next, the operation of the
controller 100 d will be described. Thecontroller 100 d generates a control signal Scd based on an operation mode signal Sm and controls the laser power control apparatus LPC4. Specifically, in the case where the CD drive is used, theoperational amplifier 6 andvariable gain circuit 9 of the DVD laser power control unit LPdvd_4 are turned off so that a laser diode LD2 will not emit light. Accordingly, only the CD laser power control unit LPcd_1 functions and thus the laser power of a laser diode LD1 is appropriately controlled. - On the other hand, in the case where the DVD drive is used, the
controller 100 d turns off the offsetadjuster 1,variable gain circuit 2, sample/hold circuit 3, andoperational amplifier 4 of the CD laser power control unit LPcd_1. Accordingly, only the DVD laser power control unit LPdvd_4 functions and thus the laser power of the laser diode LD2 is appropriately controlled. - (Fifth Embodiment)
- Referring to
FIG. 5 , a laser power control apparatus according to the present embodiment will be described. A laser power control apparatus LPC5 is a modified version of the laser power control apparatus LPC1 shown inFIG. 1 , in which the laser power control unit LPdvd_1 is replaced with a DVD laser power control unit LPdvd_5 and the controller 10 a is replaced with a controller 10 e. In the DVD laser power control unit LPdvd_5, anoperational amplifier 6 is connected between theadder 20 and amplification unit U of the CD laser power control unit LPcd_1 through ajunction 12 instead of thejunction 11. - A laser intensity signal PD0 (PD01) which is an output from a
front monitor 8 is offset adjusted by an offsetadjuster 1 and then inputted to theoperational amplifier 6. That is, the laser power control apparatus LPC5 has an effect of accommodating the difference in the light emission levels of two different types of lasers, as does the aforementioned sample/hold circuit 3 of the laser power control apparatus LPC1. In the present embodiment, by sharing the offsetadjuster 1 with the CD laser power control unit LPcd_1 and the DVD laser power control unit LPdvd_5, the laser power control apparatus LPC5 can be reduced in circuit size compared to the laser power control apparatus LPC3. - Next, the operation of the controller 10 e will be described. The
controller 100 e generates a control signal Sce based on an operation mode signal Sm and controls the laser power control apparatus LPC5. Specifically, in the case where the CD drive is used, theoperational amplifier 6 of the DVD laser power control unit LPdvd_5 is turned off so that a laser diode LD2 will not emit light. Accordingly, only the CD laser power control unit LPcd_1 functions and thus the laser power of the laser diode LD1 is appropriately controlled. - On the other hand, in the case where the DVD drive is used, the
controller 100 e turns off thevariable gain circuit 2, sample/hold circuit 3, andoperational amplifier 4 of the CD laser power control unit LPcd_1. Note that the offset value of the offsetadjuster 1 is changed to a value appropriate for the laser diode LD2. That is, in the present embodiment, thecontroller 100 e changes the offset value of the offsetadjuster 1 between at least two types, i.e., CD and DVD applications. - (Sixth Embodiment)
- Referring to
FIG. 6 , a laser power control apparatus according to the present embodiment will be described. A laser power control apparatus LPC6 is a modified version of the laser power control apparatus LPC5 shown inFIG. 5 , in which the laser power control unit LPdvd_5 is replaced with a DVD laser power control unit LPdvd_6 and thecontroller 100 e is replaced with acontroller 100 f. In the DVD laser power control unit LPdvd_6, avariable gain circuit 9 is additionally provided between anoperational amplifier 6 and ajunction 12. - A laser intensity signal PD0 (PD01) outputted from the
variable gain circuit 9 is offset adjusted by anadder 20 and an offsetadjuster 1, then further gain adjusted by thevariable gain circuit 9, and then inputted to theoperational amplifier 6. This configuration provides the same advantageous effect as that obtained by the laser power control apparatus LPC3 shown inFIG. 3 . In addition, by sharing the offsetadjuster 1 and theadder 20 with the CD laser power control unit LPcd_1 and the DVD laser power control unit LPdvd_6, the laser power control apparatus LPC6 can be reduced in circuit size compared to the laser power control apparatus LPC3. - Next, the operation of the
controller 100 f will be described. Thecontroller 100 f generates a control signal Scf based on an operation mode signal Sm and controls the laser power control apparatus LPC6. Specifically, in the case where the CD drive is used, theoperational amplifier 6 andvariable gain circuit 9 of the DVD laser power control unit LPdvd_6 are turned off so that a laser diode LD2 will not emit light. Accordingly, only the CD laser power control unit LPcd_1 functions and thus the laser power of a laser diode LD1 is appropriately controlled. - On the other hand, in the case where the DVD drive is used, the
controller 100 f turns off thevariable gain circuit 2, sample/hold circuit 3, andoperational amplifier 4 of the CD laser power control unit LPcd_1. Note that the offset value of the offsetadjuster 1 is changed to a value appropriate for the laser diode LD2. Thevariable gain circuits - (Seventh Embodiment)
- Referring to
FIG. 7 , a laser power control apparatus according to the present embodiment will be described. A laser power control apparatus LPC7 is a modified version of the laser power control apparatus LPC6 shown inFIG. 6 , in which the laser power control unit LPdvd_6 is replaced with a DVD laser power control unit LPdvd_7 and thecontroller 100 f is replaced with acontroller 100 g. In the DVD laser power control unit LPdvd_7, the reference potential PD2 ref of theoperational amplifier 6 is replaced with avariable voltage source 25. By this, the reference potential can be set to a given value within a predetermined range, and therefore the amplification characteristics provided by theoperational amplifier 6 can be more minutely adjusted than the case of the laser power control apparatus LPC6. - Next, the operation of the
controller 100 g will be described. Thecontroller 100 g generates a control signal Scg based on an operation mode signal Sm and controls the laser power control apparatus LPC7. Specifically, in the case where the CD drive is used, theoperational amplifier 6 andvariable gain circuit 9 of the DVD laser power control unit LPdvd_7 are turned off so that a laser diode LD2 will not emit light. Accordingly, only the CD laser power control unit LPcd_1 functions and thus the laser power of a laser diode LD1 is appropriately controlled. - On the other hand, in the case where the DVD drive is used, the
controller 100 g turns off thevariable gain circuit 2, sample/hold circuit 3, andoperational amplifier 4 of the CD laser power control unit LPcd_1. Note that the offset value of an offsetadjuster 1 is changed to a value appropriate for the laser diode LD2. Thevariable gain circuits variable voltage sources - (Eighth Embodiment)
- Referring to
FIG. 8 , a laser power control apparatus according to the present embodiment will be described. A laser power control apparatus LPC8 is a modified version of the laser power control apparatus LPC1 shown inFIG. 1 , in which the laser power control unit LPdvd_1 is replaced with a DVD laser power control unit LPdvd_8 and thecontroller 100 a is replaced with acontroller 100 h. In the DVD laser power control unit LPdvd_8, a laser intensity signal S2, which is an output from avariable gain circuit 2 of a CD laser power control unit LPcd_1, is inputted to anoperational amplifier 6 of the DVD laser power control unit LPdvd_8 through ajunction 13. That is, this configuration is such that in the laser power control apparatus LPC3 shown inFIG. 3 thevariable gain circuit 9, offsetadjuster 18, andadder 22 of the DVD laser power control unit LPdvd_3 are eliminated and the functions of the eliminated components are performed by the offsetadjuster 1,variable gain circuit 9, andadder 20 of the CD laser power control unit LPcd_1. With this configuration, the laser power control apparatus LPC8 can be reduced in circuit size compared to the laser power control apparatus LPC3. - Next, the operation of the
controller 100 h will be described. Thecontroller 100 h generates a control signal Sch based on an operation mode signal Sm and controls the laser power control apparatus LPC8. Specifically, in the case where the CD drive is used, theoperational amplifier 6 of the DVD laser power control unit LPdvd_8 is turned off so that a laser diode LD2 will not emit light. Accordingly, only the CD laser power control unit LPcd_1 functions and thus the laser power of a laser diode LD1 is appropriately controlled. - On the other hand, in the case where the DVD drive is used, the
controller 100 h turns off thevariable gain circuit 2, sample/hold circuit 3, andoperational amplifier 4 of the CD laser power control unit LPcd_1. Note that the offset value of the offsetadjuster 1 and the gain value of thevariable gain circuit 2 are changed to values appropriate for the laser diode LD2. - (Ninth Embodiment)
- Referring to
FIG. 9 , a laser power control apparatus according to the present embodiment will be described. A laser power control apparatus LPC9 is a modified version of the laser power control apparatus LPC8 shown inFIG. 8 , in which the laser power control unit LPdvd_8 is replaced with a DVD laser power control unit LPdvd_9 and thecontroller 100 h is replaced with a controller 100 i. In the DVD laser power control unit LPdvd_9, the reference potential PD2 ref of theoperational amplifier 6 is replaced with avariable voltage source 25. By this, the reference potential can be set to an appropriate value within a predetermined range, and therefore the amplification provided by theoperational amplifier 6 can be more minutely adjusted than the case of the laser power control apparatus LPC8. - Next, the operation of the controller 100 i will be described. The controller 100 i generates a control signal Sci based on an operation mode signal Sm and controls the laser power control apparatus LPC9. Specifically, in the case where the CD drive is used, the
operational amplifier 6 of the DVD laser power control unit LPdvd_9 is turned off so that a laser diode LD2 will not emit light. Accordingly, only the CD laser power control unit LPcd_1 functions and thus the laser power of a laser diode LD1 is appropriately controlled. - On the other hand, in the case where the DVD drive is used, the controller 100 i turns off the sample/
hold circuit 3 andoperational amplifier 4 of the CD laser power control unit LPcd_1. Then, the offset value of an offsetadjuster 1 and the gain value of avariable gain circuit 2 are changed to values appropriate for the laser diodes LD1 and LD2. The values of thevariable voltage sources - (Tenth Embodiment)
- Referring to
FIG. 10 , a laser power control apparatus according to the present embodiment will be described. A laser power control apparatus LPC10 is a modified version of the laser power control apparatus LPC8 shown inFIG. 8 , in which the laser power control unit LPdvd_8 is replaced with a DVD laser power control unit LPdvd_10 and thecontroller 100 h is replaced with a controller 100 j. In the DVD laser power control unit LPdvd_10, a laser intensity signal S3, which is an output from a sample/hold circuit 3 of a CD laser power control unit LPcd_1, is inputted to anoperational amplifier 6 of the DVD laser power control unit LPdvd_10 through ajunction 14. By this, it is possible to input to the operational amplifier 6 alaser intensity signal 3 from which high-frequency noise has been eliminated by a filter provided in the sample/hold circuit 3. - Next, the operation of the controller 100 j will be described. The controller 100 j generates a control signal Scj based on an operation mode signal Sm and controls the laser power control apparatus LPC10. Specifically, in the case where the CD drive is used, the
operational amplifier 6 of the DVD laser power control unit LPdvd_10 is turned off so that a laser diode LD2 will not emit light. Accordingly, only the CD laser power control unit LPcd_1 functions and thus the laser power of a laser diode LD1 is appropriately controlled. - On the other hand, in the case where the DVD drive is used, the controller 100 j turns off an
operational amplifier 4 of the CD laser power control unit LPcd_1, while allowing the sample/hold circuit 3 to operate at all times. Note that the offset value of an offsetadjuster 1 and the gain value of avariable gain circuit 2 are changed to values appropriate for the laser diodes LD1 and LD2. - (Eleventh Embodiment)
- Referring to
FIG. 11 , a laser power control apparatus according to the present embodiment will be described. A laser power control apparatus LPC11 is a modified version of the laser power control apparatus LPC10 shown inFIG. 10 , in which the laser power control unit LPdvd_10 is replaced with a DVD laser power control unit LPdvd_11 and the controller 100 j is replaced with acontroller 100 k. In the DVD laser power control unit LPdvd_11, the reference potential PD2 ref of theoperational amplifier 6 is replaced with avariable voltage source 25. By this, the reference potential can be set to an appropriate value within a predetermined range, and therefore the amplification characteristics provided by theoperational amplifier 6 can be more minutely adjusted than the case of the laser power control apparatus LPC10. - Next, the operation of the
controller 100 k will be described. Thecontroller 100 k generates a control signal Sck based on an operation mode signal Sm and controls the laser power control apparatus LPC11. Specifically, in the case where the CD drive is used, theoperational amplifier 6 of the DVD laser power control unit LPdvd_11 is turned off so that a laser diode LD2 will not emit light. Accordingly, only the CD laser power control unit LPcd_1 functions and thus the laser power of a laser diode LD1 is appropriately controlled. - On the other hand, in the case where the DVD drive is used, the
controller 100 k turns off anoperational amplifier 4 of the CD laser power control unit LPcd_1, while allowing a sample/hold circuit 3 to operate at all times. Note that the offset value of an offsetadjuster 1 and the gain value of avariable gain circuit 2 are changed to values appropriate for the laser diodes LD1 and LD2. The values ofvariable voltage sources - (Twelfth Embodiment)
- Referring to
FIG. 12 , a laser power control apparatus according to the present embodiment will be described. A laser power control apparatus LPC12 is a modified version of the laser power control apparatus LPC11 shown inFIG. 11 , in which the laser power control unit LPdvd_11 is replaced with a DVD laser power control unit LPdvd_12 and thecontroller 100 k is replaced with a controller 100 l. In the DVD laser power control unit LPdvd_12, theoperational amplifier 6 and thevariable voltage source 25 are eliminated from the DVD laser power control unit LPdvd_11. Further, a CD laser drive control signal LDIc, which is outputted from an amplification unit U of a CD laser power control unit LPcd_1, is inputted to a transistor PNP. - That is, all the amplification functions of the drive current of a laser diode LD2 are performed by the amplification unit U of the CD laser power control unit LPcd_1, whereby the circuit size of a
variable gain circuit 2 of the laser power control apparatus LPC12 can be reduced. Note that the DVD laser power control unit LPdvd_12, which only includes the transistor PNP, can control the power of DVD laser light Ld of the laser diode LD2, based on a CD laser drive control signal LDIc. - Next, the operation of the controller 100 l will be described. The controller 100 l generates a control signal Scl based on an operation mode signal Sm and controls the laser power control apparatus LPC12. Specifically, in the case where the CD drive is used, the transistor PNP is turned off and stopped so that the laser diode LD2 will not emit light. Accordingly, only the CD laser power control unit LPcd_1 functions and thus the laser power of a laser diode LD1 is appropriately controlled.
- On the other hand, in the case where the DVD drive is used, the controller 100 l turns off a
laser drive circuit 7 of the CD laser power control unit LPcd_1, while allowing a sample/hold circuit 3 to operate at all times. Note that the offset value of an offsetadjuster 1 and the gain value of thevariable gain circuit 2 are changed to values appropriate for the laser diodes LD1 and LD2. The values of avariable voltage source 5 and thevariable gain circuit 2 are fixed to predetermined values. - (Thirteenth Embodiment)
- Referring to
FIG. 13 , a laser power control apparatus according to the present embodiment will be described. A laser power control apparatus LPC13 is a modified version of the laser power control apparatus LPC12 shown inFIG. 12 , in which the CD laser power control unit LPcd_1 is replaced with a CD laser power control unit LPcd_13 and the controller 100 l is replaced with acontroller 100 m. In the CD laser power control unit LPcd_13, a polarity reverser 16 (referred to as “POL sel” in the drawing) is additionally provided between anadder 20 and afront monitor 8. In other words, it can be said that thepolarity reverser 16 is inserted between the CD laser power control unit LPcd_13 and thefront monitor 8. - The
polarity reverser 16 has the function of reversing the polarity of a signal to be inputted, in response to an instruction from thecontroller 100 m, and outputting the signal. Specifically, a laser intensity signal PD0 (PD01) outputted from thefront monitor 8 undergoes a polarity reversal, if necessary, and then is inputted to the CD laser power control unit LPcd_13. More specifically, in the case where the CD laser power control unit LPcd_13 and a DVD laser power control unit LPdvd_12 have different control polarities, the polarity of the laser intensity signal PD0 is reversed depending on the diode to be driven (i.e., either a laser diode LD1 or a laser diode LD2). - Next, the operation of the controller loom will be described. The
controller 100 m generates a control signal Scm based on an operation mode signal Sm and controls the laser power control apparatus LPC13. Specifically, in the case where the CD drive is used, a transistor PNP is turned off and stopped so that the laser diode LD2 will not emit light. Accordingly, only the CD laser power control unit LPcd_13 functions and thus the laser power of the laser diode LD1 is appropriately controlled. - On the other hand, in the case where the DVD drive is used, the
controller 100 m turns off alaser drive circuit 7 of the CD laser power control unit LPcd_13, while allowing a sample/hold circuit 3 to operate at all times. Note that the offset value of an offsetadjuster 1 and the gain value of avariable gain circuit 2 are changed to values appropriate for the laser diodes LD1 and LD2. The values of avariable voltage source 5 and thevariable gain circuit 2 are fixed to predetermined values. In the case where the CD laser power control unit LPcd_13 and the DVD laser power control unit LPdvd_12 have different control polarities, the polarity of a laser intensity signal PD0 (PD01) is reversed by thepolarity reverser 16, depending on the diode to be driven (i.e., either the laser diode LD1 or the laser diode LD2). - (Fourteenth Embodiment)
- Referring to
FIG. 14 , a laser power control apparatus according to the present embodiment will be described. A laser power control apparatus LPC14 is a modified version of the laser power control apparatus LPC12 shown inFIG. 12 , in which the CD laser power control unit LPcd_1 is replaced with a CD laser power control unit LPcd_14 and the controller 100 l is replaced with acontroller 100 n. In the CD laser power control unit LPcd_14, theoperational amplifier 4 is replaced with a polarity-reversibleoperational amplifier 4′. With this configuration, in the case where the CD laser power control unit LPcd_14 and a DVD laser power control unit LPdvd_12 have different control polarities, as with the laser power control apparatus LPC13, the polarity of the polarity-reversibleoperational amplifier 4′ is reversed depending on the diode to be driven (i.e., either a laser diode LD1 or a laser diode LD2). - Next, the operation of the
controller 100 n will be described. Thecontroller 100 n generates a control signal Scn based on an operation mode signal Sm and controls the laser power control apparatus LPC14. Specifically, in the case where the CD drive is used, a transistor PNP is turned off and stopped so that the laser diode LD2 will not emit light. Accordingly, only the CD laser power control unit LPcd_14 functions and thus the laser power of the laser diode LD1 is appropriately controlled. - On the other hand, in the case where the DVD drive is used, the
controller 100 n turns off alaser drive circuit 7 of the CD laser power control unit LPcd_14, while allowing a sample/hold circuit 3 to operate at all times. Note that the offset value of an offsetadjuster 1 and the gain value of avariable gain circuit 2 are changed to values appropriate for the laser diodes LD1 and LD2. The values of avariable voltage source 5 and thevariable gain circuit 2 are fixed to predetermined values. In the case where the CD laser power control unit LPcd_14 and the DVD laser power control unit LPdvd_12 have different control polarities, the polarity of the polarity-reversibleoperational amplifier 4′ is reversed depending on the diode to be driven (i.e., either the laser diode LD1 or the laser diode LD2). - (Fifteenth Embodiment)
- Referring to
FIG. 15 , a laser power control apparatus according to the present embodiment will be described. The configuration of a laser power control apparatus LPC15 is the same as that of the laser power control apparatus LPC14 shown inFIG. 14 , except that thecontroller 100 n is replaced with a controller 100 o. - In the present embodiment, a polarity-reversible
operational amplifier 4′ includes therein a switch SW1 and a switch SW2. By controlling the operation timing of the two types of switches SW1 and SW2 by the controller 100 o, the output polarity can be reversed. - (Sixteenth Embodiment)
- Referring to
FIG. 16 , a laser power control apparatus according to the present embodiment will be described. As shown inFIG. 16 , a laser power control apparatus LPC16 includes a laser diode LD1,laser drive circuit 7, afront monitor 8, aback monitor 19, anoperational amplifier 41, avariable voltage source 51, a sample/hold circuit 31, a sample/hold circuit 32, avariable gain circuit 2, an offsetadjuster 1, anadder 20, anoperational amplifier 42, avariable voltage source 52, aswitch 60, a DVD laser power control unit LPdvd_10, and acontroller 100 q. Theoperational amplifiers operational amplifier 6 is composed of a positive comparator. - The
switch 60 includes aswitch 60 a and aswitch 60 b. Theswitch 60 a selects one of thefront monitor 8, the sample/hold circuit 32, and the sample/hold circuit 31 based on the intensity of an output signal from theback monitor 19. Theswitch 60 b selects either theswitch 60 a or theback monitor 19 based on the intensity of an output signal from theback monitor 19. Specifically, theswitch 60 selects one of the outputs from the sample/hold circuit 31, the sample/hold circuit 32, and thefront monitor 8 based on an output from theback monitor 19 and outputs the selected output to the DVD laser power control unit LPdvd_10. Note that the order of connection of the offset adjuster, the variable gain circuit, and the sample/hold circuit is not limited to that described above; the order of connection may be changed appropriately. - Next, the operation of the
controller 100 q will be described. Thecontroller 100 q generates a control signal Scq based on an operation mode signal Sm and controls the laser power control apparatus LPC16. Specifically, in the case where the CD drive is used, theoperational amplifier 6 is turned off so that a laser diode LD2 will not emit light. - On the other hand, in the case where the DVD drive is used, the
controller 100 q controls the components in the following manner. - In the case where the
switch 60 a selects the sample/hold circuit 31 and theswitch 60 b selects theswitch 60 a, thecontroller 100 q turns off thevariable gain circuit 2, the sample/hold circuit 32, theoperational amplifier 41, and theoperational amplifier 42. Then, when the laser diode LD1 or LD2 emits light, thecontroller 100 q changes the offset value of the offsetadjuster 1. The sample/hold circuit 31 is allowed to operate at all times. - In the case where the
switch 60 a selects the sample/hold circuit 32 and theswitch 60 b selects theswitch 60 a, thecontroller 100 q turns off the sample/hold circuit 31, theoperational amplifier 41, and theoperational amplifier 42. Then, when the laser diode LD1 or LD2 emits light, thecontroller 100 q changes the offset value of the offset adjuster land the gain of thevariable gain circuit 2. The sample/hold circuit 31 is allowed to operate at all times. - In the case where the
switch 60 a selects theback monitor 19 and theswitch 60 b selects theswitch 60 a, thecontroller 100 q turns off the offsetadjuster 1, thevariable gain circuit 2, the sample/hold circuit 31, the sample/hold circuit 32, theoperational amplifier 41, and theoperational amplifier 42. - In the case where the
switch 60 b selects theback monitor 19, thecontroller 100 q turns off the offsetadjuster 1, thevariable gain circuit 2, the sample/hold circuit 31, the sample/hold circuit 32, and theoperational amplifier 41, and theoperational amplifier 42. - This configuration allows the controller to select from a plurality of characteristics depending on the situation, whereby flexibility is increased. Further, since the back monitor can be used, it is also possible to control a laser power in a conventional system. Therefore, this configuration can be applied to combination drives where a reduction in size is sought.
- While the invention has been described in detail, the foregoing description is in all aspects illustrative and not restrictive. It is understood that numerous other modifications and variations can be devised without departing from the scope of the invention.
Claims (20)
1. A laser power control apparatus for controlling an output of laser light which is exclusively applied onto a first optical disk and a second optical disk in a combination drive to record or read information thereon or therefrom, the apparatus comprising:
first laser light generating means for generating first laser light to be applied onto the first optical disk;
first drive current generating means for generating a drive current of the first laser light generating means;
second laser light generating means for generating second laser light to be applied onto the second optical disk;
second drive current generating means for generating a drive current of the second laser light generating means;
laser light intensity detection means for exclusively collecting the first laser light and the second laser light and generating a first laser light intensity signal which indicates an intensity of the collected laser light;
first laser light generating current control means for controlling the first laser light generating means based on the first laser light intensity signal; and
second laser light generating current control means for controlling the second laser light generating means based on the first laser light intensity signal.
2. The laser power control apparatus according to claim 1 , wherein the first laser light generating current control means includes:
first variable gain means for amplifying the first laser light intensity signal with a first predetermined gain, so as to offset a difference in intensity between the first laser light and the second laser light.
3. The laser power control apparatus according to claim 2 , wherein the first laser light generating current control means further includes first offset adjusting means for offset adjusting the first laser light intensity signal with a first predetermined offset value, so as to further offset a difference in intensity between the first laser light and the second laser light.
4. The laser power control apparatus according to claim 1 , wherein the second laser light generating current control means includes second variable gain means for amplifying the first laser light intensity signal with a second predetermined gain, so as to offset a difference in intensity between the first laser light and the second laser light.
5. The laser power control apparatus according to claim 4 , wherein the second laser light generating current control means further includes second offset adjusting means for offset adjusting the first laser light intensity signal with a second predetermined offset value, so as to further offset a difference in intensity between the first laser light and the second laser light.
6. The laser power control apparatus according to claim 4 , wherein the second laser light generating current control means includes an operational amplifier for amplifying the first laser light intensity signal having been amplified with the second predetermined gain, based on a difference between the amplified first laser light intensity signal and a first predetermined reference potential.
7. The laser power control apparatus according to claim 6 , wherein the first predetermined reference potential is variable.
8. The laser power control apparatus according to claim 1 , wherein the second laser light generating current control means controls the second laser light generating means based on the laser light intensity signal having been offset adjusted.
9. The laser power control apparatus according to claim 8 , wherein the second laser light generating current control means includes second variable gain means for amplifying the laser light intensity signal having been offset adjusted, with a second predetermined gain.
10. The laser power control apparatus according to claim 9 , wherein the second laser light generating current control means includes an operational amplifier for amplifying the laser light intensity signal having been amplified with the second predetermined gain, based on a different between the amplified laser light intensity signal and a second predetermined reference potential.
11. The laser power control apparatus according to claim 10 , wherein the second predetermined reference potential is variable.
12. The laser power control apparatus according to claim 2 , wherein the second laser light generating current control means includes an operational amplifier for amplifying a laser light intensity signal having been amplified with the first predetermined gain, based on a difference between the amplified first laser light intensity signal and a second predetermined reference potential.
13. The laser power control apparatus according to claim 12 , wherein the second predetermined reference potential is variable.
14. The laser power control apparatus according to claim 2 , wherein
the first laser light generating current control means further includes:
a sample/hold circuit for sampling and holding the first laser light intensity signal having been amplified with the first predetermined gain, and
an operational amplifier amplifies the sampled and held first laser light intensity signal based on a difference between the sampled and held first laser light intensity signal and a second predetermined reference potential.
15. The laser power control apparatus according to claim 14 , wherein the second predetermined reference potential is variable.
16. The laser power control apparatus according to claim 1 , wherein the second drive current generating means is controlled by the first laser light generating current control means.
17. The laser power control apparatus according to claim 16 , wherein the first laser light generating current control means further includes a polarity reverser for reversing a polarity of the first laser light intensity signal.
18. The laser power control apparatus according to claim 12 , wherein a polarity of the operational amplifier is variable.
19. The laser power control apparatus according to claim 12 , wherein a polarity of the operational amplifier is variable at a predetermined timing.
20. The laser power control apparatus according to claim 1 , further comprising:
second laser light intensity detection means for collecting the second laser light and generating a second laser light intensity signal;
a first sample/hold circuit for sampling and holding the first laser light intensity signal;
a variable gain circuit for amplifying the first laser light intensity signal with a predetermined gain;
a second sample/hold circuit for sampling and holding the first laser light intensity signal having been amplified with the predetermined gain;
a first switch for selecting one selected from the group consisting of an output from the first sample/hold circuit, an output from the second sample/hold circuit, and the first laser light intensity signal, based on the second laser light intensity signal, and outputting the selected one; and
a second switch for selecting one of an output from the first switch and the first laser light intensity signal based on the second laser light intensity signal, and outputting the selected one, wherein
the second laser light generating current control means controls the second laser light generating means based on the output from the second switch.
Priority Applications (1)
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US11/812,292 US7548570B2 (en) | 2003-09-04 | 2007-06-18 | Laser power control apparatus |
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JP2003-313065 | 2003-09-04 | ||
JP2003313065A JP4309212B2 (en) | 2003-09-04 | 2003-09-04 | Laser power control device |
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US11/812,292 Division US7548570B2 (en) | 2003-09-04 | 2007-06-18 | Laser power control apparatus |
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US20050053107A1 true US20050053107A1 (en) | 2005-03-10 |
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US10/886,589 Abandoned US20050053107A1 (en) | 2003-09-04 | 2004-07-09 | Laser power control apparatus |
US11/812,292 Active 2025-03-04 US7548570B2 (en) | 2003-09-04 | 2007-06-18 | Laser power control apparatus |
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Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US11/812,292 Active 2025-03-04 US7548570B2 (en) | 2003-09-04 | 2007-06-18 | Laser power control apparatus |
Country Status (6)
Country | Link |
---|---|
US (2) | US20050053107A1 (en) |
EP (1) | EP1513143A3 (en) |
JP (1) | JP4309212B2 (en) |
KR (1) | KR20050025235A (en) |
CN (2) | CN1284145C (en) |
TW (1) | TW200511230A (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20060215532A1 (en) * | 2005-03-25 | 2006-09-28 | Yuanping Zhao | Optical disc recorder laser power control |
US20090252004A1 (en) * | 2005-09-09 | 2009-10-08 | Pioneer Corporation | Light beam output control device, light beam emission control program, and recording medium on which light beam emission control program is recorded |
US20110199673A1 (en) * | 2010-02-15 | 2011-08-18 | Panasonic Corporation | Integrated optical device and optical pickup device using the same |
US20120236887A1 (en) * | 2011-03-18 | 2012-09-20 | Semiconductor Components Industries, Llc | Optical pickup apparatus, integrated circuit, and method for controlling laser output of optical pickup apparatus |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20030002552A1 (en) * | 2001-06-19 | 2003-01-02 | Sony Corporation | Laser diode drive circuit and amplifying circuit for optical disc recording and/or reproducing apparatus |
US6724792B2 (en) * | 2002-09-12 | 2004-04-20 | The Boeing Company | Laser diode arrays with replaceable laser diode bars and methods of removing and replacing laser diode bars |
US6738339B2 (en) * | 2000-02-03 | 2004-05-18 | Samsung Electronics Co., Ltd. | Laser diode driver, method of driving the laser diode driver, and method of initializing an optical recording and reproducing apparatus |
Family Cites Families (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP4604304B2 (en) * | 1999-07-09 | 2011-01-05 | ソニー株式会社 | Laser apparatus, optical head, and optical recording / reproducing apparatus |
AU3223501A (en) * | 2000-02-10 | 2001-08-20 | Matsushita Electric Industrial Co., Ltd. | Laser drive device, optical head, and optical information processor |
JP2001236726A (en) * | 2000-02-17 | 2001-08-31 | Sanyo Electric Co Ltd | Composite drive assembly |
JP2001244555A (en) * | 2000-03-01 | 2001-09-07 | Pioneer Electronic Corp | Automatic power control circuit |
JP2002352457A (en) * | 2001-05-24 | 2002-12-06 | Sony Corp | Optical pickup |
DE10160378A1 (en) * | 2001-12-10 | 2003-06-18 | Thomson Brandt Gmbh | Playback or recording device for different optical recording media |
JP2003228867A (en) | 2002-01-31 | 2003-08-15 | Toshiba Corp | Optical pickup device and optical disk drive |
-
2003
- 2003-09-04 JP JP2003313065A patent/JP4309212B2/en not_active Expired - Lifetime
-
2004
- 2004-06-23 EP EP04014731A patent/EP1513143A3/en not_active Withdrawn
- 2004-06-23 TW TW093118030A patent/TW200511230A/en unknown
- 2004-07-08 KR KR1020040052960A patent/KR20050025235A/en not_active Application Discontinuation
- 2004-07-09 US US10/886,589 patent/US20050053107A1/en not_active Abandoned
- 2004-08-16 CN CNB2004100560955A patent/CN1284145C/en not_active Expired - Fee Related
- 2004-08-16 CN CN200610077710XA patent/CN100407312C/en not_active Expired - Fee Related
-
2007
- 2007-06-18 US US11/812,292 patent/US7548570B2/en active Active
Patent Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6738339B2 (en) * | 2000-02-03 | 2004-05-18 | Samsung Electronics Co., Ltd. | Laser diode driver, method of driving the laser diode driver, and method of initializing an optical recording and reproducing apparatus |
US20040196773A1 (en) * | 2000-02-03 | 2004-10-07 | Samsung Electronics Co., Ltd. | Laser diode driver, method of driving the laser diode driver, and method of initializing an optical recording and reproducing apparatus |
US20040196772A1 (en) * | 2000-02-03 | 2004-10-07 | Samsung Electronics Co., Ltd. | Laser diode driver, method of driving the laser diode driver, and method of initializing an optical recording and reproducing apparatus |
US20030002552A1 (en) * | 2001-06-19 | 2003-01-02 | Sony Corporation | Laser diode drive circuit and amplifying circuit for optical disc recording and/or reproducing apparatus |
US6724793B2 (en) * | 2001-06-19 | 2004-04-20 | Sony Corporation | Laser diode drive circuit and amplifying circuit for optical disc recording and/or reproducing apparatus |
US20040165502A1 (en) * | 2001-06-19 | 2004-08-26 | Sony Corporation | Laser diode drive circuit and amplifying circuit for optical disc recording and/or reproducing apparatus |
US6724792B2 (en) * | 2002-09-12 | 2004-04-20 | The Boeing Company | Laser diode arrays with replaceable laser diode bars and methods of removing and replacing laser diode bars |
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20060215532A1 (en) * | 2005-03-25 | 2006-09-28 | Yuanping Zhao | Optical disc recorder laser power control |
US7636377B2 (en) * | 2005-03-25 | 2009-12-22 | Lsi Corporation | Optical disc recorder laser power control |
US20090252004A1 (en) * | 2005-09-09 | 2009-10-08 | Pioneer Corporation | Light beam output control device, light beam emission control program, and recording medium on which light beam emission control program is recorded |
US20110199673A1 (en) * | 2010-02-15 | 2011-08-18 | Panasonic Corporation | Integrated optical device and optical pickup device using the same |
US20120236887A1 (en) * | 2011-03-18 | 2012-09-20 | Semiconductor Components Industries, Llc | Optical pickup apparatus, integrated circuit, and method for controlling laser output of optical pickup apparatus |
US8427917B2 (en) * | 2011-03-18 | 2013-04-23 | Semiconductor Components Industries, Llc | Optical pickup apparatus, integrated circuit, and method for controlling laser output of optical pickup apparatus |
Also Published As
Publication number | Publication date |
---|---|
EP1513143A2 (en) | 2005-03-09 |
US20070248129A1 (en) | 2007-10-25 |
CN100407312C (en) | 2008-07-30 |
KR20050025235A (en) | 2005-03-14 |
TW200511230A (en) | 2005-03-16 |
CN1855256A (en) | 2006-11-01 |
CN1591594A (en) | 2005-03-09 |
US7548570B2 (en) | 2009-06-16 |
JP4309212B2 (en) | 2009-08-05 |
CN1284145C (en) | 2006-11-08 |
EP1513143A3 (en) | 2007-08-29 |
JP2005085312A (en) | 2005-03-31 |
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Legal Events
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STCB | Information on status: application discontinuation |
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AS | Assignment |
Owner name: PANASONIC CORPORATION, JAPAN Free format text: CHANGE OF NAME;ASSIGNOR:MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD.;REEL/FRAME:021930/0876 Effective date: 20081001 |