Method and device for generating a stable power control signal in a cd recorder. The power control signal for controlling a laser diode may be a read level, an erase level and a write level. A pickup device outputs a feedback control signal to a read control circuit, and a read power control voltage is thus obtained. Then, the read power control voltage is inputted to a write control circuit, which generates first and second write power control voltages. The read level equals a reference voltage added by the read power control voltage, the erase level equals the read level added by the first write power control voltage, and the write level equals the erase level added by the second write power control voltage, so the read power control voltage and thus the read, erase and write levels are automatically and dynamically adjusted as the feedback control signal varies.
|
0. 17. A method for providing power control signals in an optical disk drive, comprising:
receiving a feedback control signal that is based on an intensity of a laser output of the optical disk drive;
providing a read power control signal according to the feedback control signal;
providing a first write power control signal according to the read power control signal; and
providing a second write power control signal according to the read power control signal.
0. 27. A control device for providing power control signals in an optical disk drive, comprising:
a feedback control means for receiving a feedback control signal that is based on an intensity of a laser output of the optical disk drive;
a read control means for providing a read power control signal according to the feedback control signal;
a write control means for providing a first write power control signal according to the read power control signal, and further to provide a second write power control signal according to the read power control signal.
0. 23. A control device for providing power control signals in an optical disk drive, comprising:
a feedback control circuit configured to receive a feedback control signal that is based on an intensity of a laser output of the optical disk drive;
a read control circuit configured to provide a read power control signal according to the feedback control signal;
a write control circuit configured to provide a first write power control signal according to the read power control signal, and to provide a second write power control signal according to the read power control signal.
10. A control device for generating a stable power control signal in a cd recorder, the cd recorder using a power control signal to access an optical disk, the power control signal having a read level, an erase level and a write level, the read level equaling a sum of a reference voltage and a read power control voltage, the erase level equaling a sum of the read level and a first write power control voltage, and the write level equaling a sum of the erase level and a second write power control voltage, the control device comprising:
a read control circuit having a read target value digital-to-analog converter for storing a plurality of first digital values and converting one of the first digital values into a first analog value, the read control circuit generating the read power control voltage according to the feedback control signal and the first analog value; and
a write control circuit having a write target value digital-to-analog converter for storing a plurality of second digital values and converting one of the second digital values into a second analog value, the write control circuit generating the first write power control voltage and the second write power control voltage according to the read power control voltage and the second analog value, wherein the read power control voltage is automatically and dynamically adjusted as the feedback control signal varies, such that the read level, the erase level and the write level of the power control signal are also automatically and dynamically adjusted as the read power control voltage varies.
7. A method for generating a stable power control signal in a read control circuit and a write control circuit of a cd recorder, wherein the cd recorder has a laser diode and a monitor diode, the laser diode generates a laser beam to read, erase or write a disk, the cd recorder generates a feedback control signal according to intensity of the laser beam sensed by the monitor diode, the method enables the read control circuit to generate a read power control voltage and the write control circuit to generate a first write power control voltage and a second write power control voltage, the power control signal for controlling the laser diode has a read level, an erase level and a write level, the read level equals a sum of a reference voltage and the read power control voltage, the erase level equals a sum of the read level and the first write power control voltage, and the write level equals a sum of the erase level and the second write power control voltage, the method comprising the steps of:
inputting the feedback control signal to the read control circuit to obtain the read power control voltage; and
inputting the read power control voltage to the write control circuit to generate the first write power control voltage and the second write power control voltage, wherein the read power control voltage is automatically and dynamically adjusted as the feedback control signal varies, such that the read level, the erase level and the write level of the power control signal are also automatically and dynamically adjusted as the read power control voltage varies.
1. A cd recorder having a power control signal, which has a read level, an erase level and a write level, wherein the read level equals a sum of a reference voltage and a read power control voltage, the erase level equals a sum of the read level and a first write power control voltage, and the write level equals a sum of the erase level and a second write power control voltage, the cd recorder comprising:
a pickup device for reading, erasing or writing a disk and generating a feedback control signal, the pickup device comprising:
a laser diode for receiving the power control signal, which enables the laser diode to generate a laser beam to read, erase or write the disk; and
a monitor diode for sensing intensity of the laser beam, wherein the cd recorder generates the feedback control signal according to the intensity of the laser beam sensed by the monitor diode;
a read control circuit having a read target value digital-to-analog converter for storing a plurality of first digital values and converting one of the first digital values into a first analog value, wherein the read control circuit generates the read power control voltage according to the feedback control signal and the first analog value; and
a write control circuit having a write target value digital-to-analog converter for storing a plurality of second digital values and converting one of the second digital values into a second analog value, wherein the write control circuit generates the first write power control voltage and the second write power control voltage according to the read power control voltage and the second analog value, wherein the read power control voltage is automatically and dynamically adjusted as the feedback control signal varies, such that the read level, the erase level and the write level of the power control signal are also automatically and dynamically adjusted as the read power control voltage varies.
2. The cd recorder according to
a sample and hold circuit for receiving the feedback control signal and obtaining a third analog value;
a subtracter for subtracting the third analog value from the first analog value and outputting a difference between the first and third analog values; and
a first low-pass filter for receiving the outputted difference of the subtracter and obtaining the read power control voltage.
3. The cd recorder according to
an adder for adding the read power control voltage and the second analog value together to obtain a sum, and outputting the sum to a second low-pass filter so as to obtain the first write power control voltage; and
an amplifier for receiving the first write power control voltage and obtaining the second write power control voltage.
4. The cd recorder according to
5. The cd recorder according to
6. The cd recorder according to
8. The method according to
9. The method according to
11. The control device according to
a sample and hold circuit for receiving the feedback control signal and obtaining a third analog value;
a subtracter for subtracting the third analog value from the first analog value and outputting a difference between the first and third analog values; and
a first low-pass filter for receiving the outputted difference of the subtracter and obtaining the read power control voltage.
12. The control device according to
an adder for adding the read power control voltage and the second analog value together to obtain a sum, and outputting the sum to a second low-pass filter so as to obtain the first write power control voltage; and
an amplifier for receiving the first write power control voltage and obtaining the second write power control voltage.
13. The control device according to
14. The control device according to
15. The control device according to
16. The control device according to
a pickup device for reading, erasing or writing the optical disk and generating a feedback control signal, the pickup device comprising:
a laser diode for receiving the power control signal, which enables the laser diode to generate a laser beam to read, erase or write the disk; and
a monitor diode for sensing intensity of the laser beam, wherein the cd recorder generates the feedback control signal according to the intensity of the laser beam sensed by the monitor diode.
0. 18. The method according to claim 17, further comprising:
inputting the feedback control signal to a read control circuit of the optical disk drive to generate the read power control signal; and
inputting the read power control signal to a write control circuit of the optical disk drive to generate the first write power control signal and the second write power control signal.
0. 19. The method according to claim 17, wherein the laser output has a read level, an erase level, and a write level, further wherein:
the read level equals a sum of a reference signal of the laser output and the read power control signal;
the erase level equals a sum of the read level and the first write power control signal; and
the write level equals a sum of the erase level and the second write power control signal.
0. 20. The method according to claim 19, wherein the read power control signal is automatically and dynamically adjusted as the feedback control signal varies, such that the read level, the erase level and the write level are also automatically and dynamically adjusted as the read power control signal varies.
0. 21. The method according to claim 19, wherein the read level enables a laser diode associated with the laser output to generate a read power, the erase level enables the laser diode to generate an erase power, and the write level enables the laser diode to generate a write power.
0. 22. The method according to claim 17, wherein the read power control signal is generated in a close loop control manner by feeding back the feedback control signal, and the first write power control signal and the second write power control signal are generated in an open loop control manner.
0. 24. The control device according to claim 23, wherein the laser output has a read level, an erase level, and a write level, wherein:
the read level is approximately equal to a sum of a reference signal of the laser output and the read power control signal;
the erase level is approximately equal to a sum of the read level and the first write power control signal; and
the write level is approximately equal to a sum of the erase level and the second write power control signal.
0. 25. The control device according to claim 24, wherein the read control circuit is configured to automatically and dynamically adjust the read power control signal as the feedback control signal varies, enabling the read level, the erase level and the write level to also be automatically and dynamically adjusted as the read power control signal varies.
0. 26. The method according to claim 23, wherein the read control circuit generates the read power control signal in a close loop control manner by feeding back the feedback control signal, and wherein write control circuit generates the first write power control signal and the second write power control signal in an open loop control manner.
0. 28. The control device according to claim 27, wherein the laser output has a read level, an erase level, and a write level, wherein:
the read level is approximately equal to a sum of a reference signal of the laser output and the read power control signal;
the erase level is approximately equal to a sum of the read level and the first write power control signal; and
the write level is approximately equal to a sum of the erase level and the second write power control signal.
0. 29. The control device according to claim 28, wherein the read control means automatically and dynamically adjusts the read power control signal as the feedback control signal varies, enabling the read level, the erase level and the write level to also be automatically and dynamically adjusted as the read power control signal varies.
|
|||||||||||||||||||||||||
This application This patent application is a reissue application for commonly assigned U.S. Pat. No. 7,286,462, issued Oct. 23, 2007 from U.S. patent application Ser. No. 10/990,909 which claims the benefit of the U.S. provisional application Ser. No. 60/520,711, filed Nov. 17, 2003, the subject matter of which is incorporated herein by reference.
1. Field of the Invention
The invention relates in general to a method and a device for generating a stable power control signal in a CD recorder, and more particularly to a method for controlling a power control signal of a laser diode such that the read power control voltage is automatically and dynamically adjusted as a feedback control signal varies, and a read level, an erase level and a write level of the power control signal are also automatically and dynamically adjusted as the read power control voltage varies.
2. Description of the Related Art
When a conventional CD-RW (CD-ReWritable) recorder is writing a disk, a power control signal for controlling a laser diode may be a read level V_bias, an erase level V_erase and a write level V_write. When the recorder wants to read a CD-RW, the level of the power control signal is the read level V_bias. When the recorder is erasing data on the CD-RW disk, the level of the power control signal is the erase level V_erase. When the recorder wants to write data on the CD-RW disk, the level of the power control signal is the write level V_write. The power control signal controls the laser diode to generate a laser beam to read, erase, or write the CD-RW disk.
The CD-RW recorder further has a monitor diode for generating a current iM according to the intensity of the laser beam generated by the laser diode. An OP amplifier processes the current iM and then generates a feedback control signal FPDO.
In general, the read level V_bias, the erase level V_erase and the write level V_write are generated by generating a read power control voltage VRDCO, a first write power control voltage VW1DCO and a second write power control voltage VW2DCO. The read level V_bias equals a sum of a reference voltage Vref and the read power control voltage VRDCO, the erase level V_erase equals a sum of the read level V_bias and the first write power control voltage VW1DCO, and the write level V_write equals a sum of the erase level V_erase and the second write power control voltage VW2DCO.
The S/II 206 samples the feedback control signal FPDO according to a pulse signal E_Pulse of
However, because the circuit for generating the read power control voltage VRDCO is an open loop control system, the read power control voltage VRDCO will change as the temperature rises after a long term usage of the recorder. At this time, the read level V_bias, the first power control voltage VW1DCO and the second power control voltage VW2DCO will shift and errors occur, and the write quality is influenced.
It is therefore an object of the invention to provide a method and a device for generating a stable power control signal, wherein the method and device can effectively improve the problem of the varying power control signal caused by the temperature variation in the long-term writing process.
The invention achieves the above-identified object by providing a CD recorder having a power control signal. The power control signal has a read level, an erase level and a write level. The read level equals a sum of a reference voltage and a read power control voltage, the erase level equals a sum of the read level and a first write power control voltage, and the write level equals a sum of the erase level and a second write power control voltage. The CD recorder of the invention includes a pickup device, a read control circuit and a write control circuit. The pickup device is for reading, erasing or writing a disk and generating a feedback control signal. The pickup device includes a laser diode and a monitor diode. The laser diode receives the power control signal, which enables the laser diode to generate a laser beam to read, erase or write the disk. The monitor diode senses intensity of the laser beam. The CD recorder generates the feedback control signal according to the intensity of the laser beam sensed by the monitor diode. The read control circuit has a read target value digital-to-analog converter for storing a plurality of first digital values and converting one of the first digital values into a first analog value. The read control circuit generates the read power control voltage according to the feedback control signal and the first analog value. The write control circuit has a write target value digital-to-analog converter for storing a plurality of second digital values and converting one of the second digital values into a second analog value. The write control circuit generates the first write power control voltage and the second write power control voltage according to the read power control voltage and the second analog value. The read power control voltage is automatically and dynamically adjusted as the feedback control signal varies, such that the read level, the erase level and the write level of the power control signal are also automatically and dynamically adjusted as the read power control voltage varies.
Other objects, features, and advantages of the invention will become apparent from the following detailed description of the preferred but non-limiting embodiments. The following description is made with reference to the accompanying drawings.
Please refer to
On the other hand, the write target value digital-to-analog converter (WDAC) 410 selects one of the stored digital values, and converts the selected digital values into a second analog signal A7 for output. The read power control voltage VRDCO′, which is inputted form the A4 end, and the second analog signal A7 are added together to obtain a sum, which is inputted to the low-pass filter 408 to obtain the first write power control voltage VW1DCO′. The amplifier 412 amplifies the first write power control voltage VW1DCO′ by G′ times to obtain the second write power control voltage VW2DCO′.
In this case, the read power control voltage VRDCO′ is generated in a close loop control manner by feeding back the feedback control signal FPDO′. The first write power control voltage VW1DCO′ and the second write power control voltage VW2DCO′ are generated in an open loop control manner. Thus, when the recorder is used for a long time such that the temperature of the laser diode 301 rises, the read power control voltage VRDCO′ is automatically and dynamically adjusted as the level of the feedback control signal FPDO′ varies.
In this case, because the first write power control voltage VW1DCO′ is generated in an open loop control manner, the value of the first write power control voltage VW1DCO′ basically does not tend to vary as the temperature changes, and the relationship between VW2DCO′ and VW1DCO is only determined by the magnification power G′ of the amplifier 412. Consequently, the erase level V_erase at this time equals (Vref+VRDCO′(TP3)+VW1DCO′).
The characteristic curves of the laser diode 301 have a linear zone LN. No matter how the temperature changes, the slope in the linear zone LN is kept constant. Because the erase level V_erase is still in the linear zone after it is risen to (Vref+VRDCO′(TP3)+VW1DCO′), the erase level V_erase at this time still enables the laser diode to generate the erase power P_erase.
Before the product of the invention is shipped out, an optimum setting value is obtained after the first write power control voltage VW1DCO′ is corrected. When the recorder is used, the read power control voltage VRDCO′ is dynamically adjusted as the feedback control signal FPDO′ varies, and simultaneously enables the erase level V_erase and the write level V_write to be dynamically adjusted as the feedback control signal FPDO′ varies. So, the invention can dynamically adjust the read level V_bias, the erase level V_erase and the write level V_write with the temperature variation, such that the laser diode generates the constant read power P_bias, erase power P_erase and write power P_write to keep the write quality of the recorder.
While the invention has been described by way of example and in terms of a preferred embodiment, it is to be understood that the invention is not limited thereto. On the contrary, it is intended to cover various modifications and similar arrangements and procedures, and the scope of the appended claims therefore should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements and procedures.
| Patent | Priority | Assignee | Title |
| Patent | Priority | Assignee | Title |
| 4390781, | Jun 25 1979 | Olympus Optical Co. Ltd. | Method and apparatus for detecting focussing error signal of objective lens |
| 4512004, | Jan 24 1982 | Sony Corporation | Apparatus for optically reproducing an information signal recorded on a record disc |
| 4707648, | Nov 28 1985 | Fujitsu Limited | Focus servomechanism control system of optical disc system having offset setting means |
| 4707816, | Mar 29 1985 | Hitachi, LTD | Method and apparatus for composite wobbled and push-pull tracking servo system |
| 4730290, | Mar 20 1985 | Hitachi, LTD | Defect detecting optical apparatus enabling recording in an alternate sector or track |
| 4878211, | May 26 1986 | Pioneer Electronic Corporation | Method and apparatus for correcting the loop gain of a servo loop in accordance with measurements during open-loop operation |
| 5029155, | Nov 19 1987 | Olympus Optical Co., Ltd. | Optical information recording/reproducing apparatus in which recording power is set prior to recording |
| 5146443, | Mar 13 1990 | Pioneer Electronic Corporation | Servo apparatus for optical disk player having both open loop coarse gain control and closed loop fine gain control |
| 5199015, | Jun 18 1990 | MATSUSHITA ELECTRIC INDUSTRIAL CO , LTD | Optical recording/reproducing device having means for adjusting servo loop gain and phase characteristics |
| 5216659, | Sep 11 1991 | International Business Machines; INTERNATIONAL BUSINESS MACHINES CORPORTION A CORP OF NY | Laser power calibration by measuring laser drive current at out of focus and in focus conditions |
| 5245598, | Jun 27 1990 | Maxoptix Corporation | Method and apparatus for seek operations in an optical recording system including holding a focus error signal at track crossings |
| 5297114, | Nov 30 1990 | ASAHI KOGAKU KOGYO KABUSHIKI KAISHA A CORP OF JAPAN | Magneto-optic recording/reproduction apparatus for minimizing variation in focusing error signals caused by variation in optical source wavelength |
| 5367513, | Nov 05 1993 | International Business Machines Corporation | Focus and tracking servo decoupling system |
| 5475664, | Feb 05 1993 | Sony Corporation | Focus servo circuit apparatus with automatic bias adjustments |
| 5504726, | Apr 23 1993 | International Business Machines Corporation | Method and apparatus for calibrating focus and tracking error signals in an optical drive with measuring offsets during track jumps |
| 5563920, | Feb 17 1993 | LG ELECTROICS INC | Method of processing variable size blocks of data by storing numbers representing size of data blocks in a fifo |
| 5568464, | Nov 18 1993 | Olympus Optical Co., Ltd. | Semiconductor laser driving apparatus utilizing three current sources to control read and write light power |
| 5587985, | Mar 09 1993 | Matsushita Electric Industrial Co., Ltd. | Signal processing device for an optical information reproducing apparatus |
| 5602814, | Oct 06 1994 | International Business Machines Corporation | Calibration of write-once disks using a single disk sector |
| 5623465, | Nov 06 1991 | Sony Corporation | Optical disk player with a digital servo-control circuit incorporating a time sharing multifunctional digital filter |
| 5642340, | Jun 23 1993 | Sharp Kabushiki Kaisha | Device for controlling focus of an optical disk apparatus |
| 5677935, | Jan 11 1995 | Matsuhita Electric Industrial Co., Ltd. | Sync detecting method and sync detecting circuit |
| 5703848, | Apr 05 1994 | HEWLETT-PACKARD DEVELOPMENT COMPANY, L P | Off track detection system for ruggedized optical disk drive |
| 5710748, | Apr 05 1994 | HEWLETT-PACKARD DEVELOPMENT COMPANY, L P | Off track detection system and method for ruggedized optical disk drive |
| 5732052, | Oct 05 1994 | Canon Kabushiki Kaisha | Optical information recording and/or reproducing apparatus capable of selecting one of focusing error signals depending upon operating mode |
| 5748584, | Mar 22 1995 | NEC Corporation | Optical disk device having a focus offset controller |
| 5844920, | Nov 07 1996 | Cirrus Logic, INC | Thermal asperity compensation using multiple sync marks for retroactive and split segment data synchronization in a magnetic disk storage system |
| 6069667, | Feb 12 1997 | Matsushita Electric Industrial Co., Ltd. | Synchronizing signal detecting device |
| 6069855, | Nov 22 1996 | Sanyo Electric Co., Ltd. | Synchronous circuit and optical disk reproduction device capable of realizing more precise synchronization |
| 6157601, | Jan 21 1998 | MEDIATEK INC | Auto gain adjustment apparatus and method for focusing and tracking control of the optical pickup of an optical disc drive |
| 6269058, | Jan 04 1999 | TEXAS INSTRUMENTS INCORPORATED, A CORP OF DELAWARE | Wide capture range circuitry |
| 6404713, | Nov 16 1999 | JVC Kenwood Corporation | Method and apparatus for recording and reproducing information on and from optical disc |
| 6560173, | Apr 28 2000 | Pioneer Corporation | Servo control apparatus for optical disc player |
| 6611123, | Mar 02 2001 | FUNAI ELECTRIC CO , LTD | Servo control apparatus and gain adjusting method |
| 6628594, | Mar 05 1999 | LG Electronics Inc. | Device and method for generating writing signal for optical recording medium by controlling writing power levels for different pit portions |
| 6633523, | Apr 08 1999 | MATSUSHITA ELECTRIC INDUSTRIAL CO , LTD | Optical memory apparatus and focus servo control method |
| 6691203, | Aug 30 2000 | Promos Technologies Inc | Integrated controller to process both optical reads and optical writes of multiple optical media |
| 6731624, | Mar 01 1999 | Sony Corporation | Sync signal detection method and radio communication system |
| 6745167, | Mar 27 2001 | Lite-On It Corporation | Fuzzy-neuro method for discriminating optical disk type |
| 6757239, | Sep 01 2000 | Matsushita Electric Industrial Co., Ltd. | Optical disk having wobble patterns and block identification marks |
| 6882611, | Jun 04 2002 | Media Tek Inc. | Method and apparatus for defect detection in optical disc drives |
| 6906986, | Aug 29 2001 | TS-OPTICS CORPORATION | Apparatus and method of measuring vibration quantity and method of designing loop |
| 6934227, | Sep 06 2001 | COLLABO INNOVATIONS, INC | Optical disk device, semiconductor integrated circuit, pickup control method and vibration component detection method |
| 6970522, | Apr 16 1999 | HEWLETT-PACKARD DEVELOPMENT COMPANY L P | Data retrieval |
| 7035176, | Feb 26 2002 | Tian Holdings, LLC | Method and device for timely outputting focusing completion signal to realize focusing condition of optical pickup head |
| 7092324, | Mar 06 2002 | Samsung Electronics Co., Ltd. | Apparatus and method for stabilizing operation of disc driver in section for setting mode conversion |
| 7095693, | Mar 09 2001 | Sony Corporation | Optical disc device and control method using preceding sub-beam to detect a disc defect |
| 7120100, | Sep 20 2002 | Lite-On It Corp. | Method for preventing an optical recording device from erroneous defect detecting during writing |
| 7149169, | Nov 13 2003 | MEDIATEK INC. | Distinguishing optical disc types |
| 7242650, | Jan 23 2003 | Mediatek Incorporation | Apparatus and method for recovering clock signal extracted from prerecorded information in optical storage devices |
| 7245573, | Apr 17 2002 | Samsung Electronics Co., Ltd. | Apparatus and method for detecting sector sync signal on an optical storage medium |
| 7286462, | Nov 17 2003 | Tian Holdings, LLC | Method and device for generating a stable power control signal |
| 7298674, | Nov 17 2003 | Tian Holdings, LLC | Method and device for adjusting a control parameter of a servo of an optical drive |
| 7349310, | Nov 17 2003 | Tian Holdings, LLC | Optical disk drive for writing a re-writable optical disk and method thereof |
| 7385896, | Nov 17 2003 | Tian Holdings, LLC | Focusing controller apparatus and method for an optical disk drive |
| 7542390, | Apr 19 2004 | Tian Holdings, LLC | Method for sampling optical disc data and apparatus thereof |
| 7619956, | Nov 17 2003 | Tian Holdings, LLC | stability of a write control signal |
| 7646682, | Nov 17 2003 | Tian Holdings, LLC | Focusing controller and method thereof for an optical disk drive |
| 20010019603, | |||
| 20020009026, | |||
| 20020131350, | |||
| 20030048707, | |||
| 20030053387, | |||
| 20030147315, | |||
| 20030169649, | |||
| 20040037177, | |||
| 20040052183, | |||
| 20040130993, | |||
| 20040179451, | |||
| 20050157606, | |||
| 20050195717, | |||
| 20050251671, | |||
| 20060013083, | |||
| 20060039252, | |||
| 20060056555, | |||
| 20070237044, | |||
| 20080205240, | |||
| 20090003163, | |||
| CN1407552, | |||
| CN1481553, | |||
| CN1519667, | |||
| CN1619660, | |||
| CN1619661, | |||
| CN1619662, | |||
| CN1619668, | |||
| CN1629947, | |||
| JP10040546, | |||
| JP10083540, | |||
| JP2001067682, | |||
| JP63117336, | |||
| TW200518048, | |||
| TW200518049, | |||
| TW200518073, | |||
| TW200518078, | |||
| TW200518081, | |||
| TW200522040, | |||
| WO249023, |
| Executed on | Assignor | Assignee | Conveyance | Frame | Reel | Doc |
| Oct 22 2009 | Han Holdings, LLC | (assignment on the face of the patent) | / |
| Date | Maintenance Fee Events |
| Mar 25 2015 | M1552: Payment of Maintenance Fee, 8th Year, Large Entity. |
| Mar 13 2019 | M1553: Payment of Maintenance Fee, 12th Year, Large Entity. |
| Date | Maintenance Schedule |
| Jun 14 2014 | 4 years fee payment window open |
| Dec 14 2014 | 6 months grace period start (w surcharge) |
| Jun 14 2015 | patent expiry (for year 4) |
| Jun 14 2017 | 2 years to revive unintentionally abandoned end. (for year 4) |
| Jun 14 2018 | 8 years fee payment window open |
| Dec 14 2018 | 6 months grace period start (w surcharge) |
| Jun 14 2019 | patent expiry (for year 8) |
| Jun 14 2021 | 2 years to revive unintentionally abandoned end. (for year 8) |
| Jun 14 2022 | 12 years fee payment window open |
| Dec 14 2022 | 6 months grace period start (w surcharge) |
| Jun 14 2023 | patent expiry (for year 12) |
| Jun 14 2025 | 2 years to revive unintentionally abandoned end. (for year 12) |