KR20100117279A - Apparatus and method for controlling an optical source - Google Patents

Apparatus and method for controlling an optical source Download PDF

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Publication number
KR20100117279A
KR20100117279A KR1020090035937A KR20090035937A KR20100117279A KR 20100117279 A KR20100117279 A KR 20100117279A KR 1020090035937 A KR1020090035937 A KR 1020090035937A KR 20090035937 A KR20090035937 A KR 20090035937A KR 20100117279 A KR20100117279 A KR 20100117279A
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KR
South Korea
Prior art keywords
light source
value
output value
output
light
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KR1020090035937A
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Korean (ko)
Inventor
박현호
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엘지전자 주식회사
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Priority to KR1020090035937A priority Critical patent/KR20100117279A/en
Publication of KR20100117279A publication Critical patent/KR20100117279A/en

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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
    • G11B7/00456—Recording strategies, e.g. pulse sequences
    • 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
    • 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
    • G11B7/1267—Power calibration

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  • Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Semiconductor Lasers (AREA)

Abstract

PURPOSE: An apparatus and a method for controlling an optical source are provided to check the operating state of an optical source and control the input to the optical source according to the output of the optical source. CONSTITUTION: An apparatus for controlling an optical source comprises an optical pickup part(20) and a controller(50,70). The optical pickup part includes an optical source which emits output light corresponding to an optical medium and a unit for measuring the output of the optical source. The controller compares the output of the optical source with the target value to determine at least one of the input current, operating state, and operating characteristic of the optical source.

Description

Apparatus and Method for controlling an optical source

1 is a block diagram schematically showing an optical recording / reproducing apparatus according to one embodiment.

FIG. 2 is a detailed diagram of the corresponding part of FIG. 1, and is a block diagram illustrating the control of the current input to the light source based on the measurement of the output value of the light source and the operation state / operation tendency of the light source according to the used output value in the present invention.

FIG. 3 is a diagram illustrating an embodiment of determining an operation tendency of LD at an output value (DAC Value) of the DSP of FIG. 2.

4 is a view showing that the limit value of the DAC value, which is the output value of the DSP of FIG. 2, changes according to temperature;

5 is an upper limit of a target light output value (Target power) for each recording medium, a first MDI value for the target light output, and a DAC value based on the measured light output value (second MDI) of the light source. Or, a flow chart showing judging the operating state and propensity of the light source through setting and comparing the value of the under limit

The present invention relates to a light source control apparatus and method for checking the operating state of the light source and / or the operating tendency of the light source based on the output value of the light source, and for controlling the input value of the light source.

More specifically, the present invention measures an optical power value output from a light source configured in an optical pickup of an optical device, for example, a laser diode (LD) through a front photo diode (FPD), thereby measuring the measured optical power value ( 2 MDI) may determine whether the first MDI value for outputting a predetermined target power value (not small) satisfies the operation state (NG, GOOD) of the LD.

Also, when the output / used optical power value (second MDI) satisfies a first MDI value for generating a predetermined target power value, the DSP for the second MDI value used in the light source is used. The operation tendency of the LD can be determined by comparing the output value (DAC Value) with a predetermined upper limit / under limit.

For example, when the DSP output value (DAC Value) is greater than a predetermined upper limit, it indicates that the current input to the light source is too large, which is predicted that the life of the LD may be shortened or is input to the LD. The lifetime of the LD can be extended by controlling the current (at least to be output smaller than the upper limit).

On the other hand, when the DSP output value (DAC Value) is smaller than a predetermined under limit, it indicates that the LD is likely to deteriorate in response to the current input to the light source, thereby controlling the current input to the LD (at least). Output greater than the Under Limit).

Hereinafter, the related art related to the present invention will be described.

LD (Laser Diode), which is a light source used for optical pickup of optical devices, has a limited lifespan and LD does not control the optical current input to LD based on the output optical power value, even though LD has its own propensity to operate. Did

In addition, the visual inspection of the LD test or the judgment using the disk is not reliable and time consuming.

In addition, even if the LD test passes, the LD easily deteriorates depending on the size of the input power supply, or the service life is shortened, resulting in poor performance. There is no control to compensate for this.

In addition, although the LD output is variable (the light output becomes small when the ambient temperature rises) based on the optical pickup and the ambient temperature, the LD does not perform the optical input control reflecting this.

According to the present invention, an optical power value output from a laser diode (LD) as a light source is measured through a front photo diode (FPD), and the optical power value (second MDI) determined by the measured optical power value (second MDI) is determined in advance. It is checked whether the first MDI for outputting the power value) is satisfied to easily indicate the operation state of the light source.

In addition, the present invention indicates that when the used DAC value is greater than a predetermined upper limit, the current input to the light source is excessively large, which may shorten the life of the LD, thereby being input to the LD. The lifetime of the LD can be extended by controlling the current (outputting at least less than the upper limit).

In addition, the present invention indicates that when the used DAC value is smaller than a predetermined under limit, the LD may easily deteriorate in response to the current input to the light source, thereby reducing the current input to the LD. The control is performed to output a stable light output value by controlling (at least to be output larger than the Under Limit).

In addition, the present invention proposes to provide a stable light output by increasing the current input to the light source because the output value of the light source is reduced when the temperature of the optical device increases.

In addition, the present invention proposes to provide a stable light output by reducing the current input to the light source because the output value of the light source is increased when the temperature of the optical device is lowered.

A light source power supply control apparatus according to the present invention for achieving the above object, in the optical device in which at least one operation of recording / reproducing data on the optical medium is performed, the light source for emitting output light corresponding to each optical medium An optical pickup including a; And

At least one predetermined light output target value for each optical medium, an output value for the target value, a maximum value or a minimum value for determining the operation of the light source, and a current value input to the light source by comparing the output value of the light source. And a controller for determining at least one operation state or operation tendency of the light source.

The light source power control method according to the present invention comprises the steps of: setting at least one target light output value for each recording medium, an output value for the target light output, a maximum value or minimum value for determining the operation of the light source; Comparing the output value of the measured light source with the output value for the set target light output value; Determining an operating state of the light source based on the comparison result; And comparing the output value according to the measured / used light output value with the set maximum value / minimum value to determine an operation tendency of the light source.

Hereinafter, an apparatus and method for controlling a light source power according to an embodiment of the present invention will be described with reference to the accompanying drawings.

First, the terms used in the present invention were selected as general terms widely used at present, but in some cases, the terms arbitrarily selected by the applicant, which are described in detail in the description of the corresponding invention, the simple terms, It is to be noted that the present invention should be understood as an operation / meaning of a term other than a name of a.

1 is a block diagram 100 schematically showing an optical recording / reproducing apparatus according to an embodiment.

As shown in the figure, an optical disk 10 corresponding to an optical recording / reproducing medium, an optical pickup 20 including an LD (not shown) as a light source, and a motor corresponding to a driving unit for driving the optical medium ( 30) and a servo control unit 40 for controlling the operation of the optical pickup, an APC (Auto Power Control) 50 for controlling the input current of the LD in contact with the optical pickup including the LD, and a predetermined light output value. And a memory unit 80 in which the light is stored, a predetermined light output value, and the like, a DSP unit 60 for processing the light output value of the optical pickup unit, and a control unit 70 for controlling the system. It works.

1, the optical pickup unit 20 includes a light source for emitting output light corresponding to each optical medium (eg, BD, CD, DVD, etc.); A memory unit 80 storing at least one reference MDI value (first MDI), a maximum value, or a minimum value for a predetermined optical output target value for each optical medium; And a controller (50, 70) for comparing at least one light output value by the output value of the light source and values stored in the memory unit to determine at least one current control input to the light source, an operating state, or an operation tendency of the light source. Works with;

FIG. 2 is a detailed view of the corresponding part of FIG. 1, and a block diagram illustrating control of a current input to a light source based on measurement of an output value of the light source and an operating state / orientation of the light source according to the output value used in the present invention. 200).

As shown in the figure, the configuration, the control configuration, and the like for checking the output value of the LD 21 which is the light source configured in the optical pickup 20 of FIG.

Front Photo Diode (FPD) 23 for measuring the output power value (Watt => P = VI) of the LD 21, DSP 60 for processing the output value Volt from the FPD, and DAC from the DSP It consists of APC (Auto Power Control) Block 50 that controls the current (Iop) input to LD by using Value (Volt).

The DSP compares the A / D 61 for converting the output voltage value (second MDI) of the FPD with the first MDI for the pre-stored optical output target value (Target power). A gain unit 62 and a D / A unit 63 which perform one compensation.

Based on the above configuration, the operation state / operation propensity and control of the LD through the output value check of the LD which is the light source will be described.

LD check is performed in a close loop system to prevent damage to the product. By disc media (e.g. BD, BD DL, DVD, CD)

The power to be emitted from the LD and the output voltage of the LD for generating the power (LD output value for the target power, that is, the first MDI value) are determined and stored in the DSP or the memory. (See Table 1)

Thereafter, the second MDI value from the FPD is measured with respect to the output of the LD, and compensation is performed by a difference from the first MDI value for outputting the target power from the DSP.

The DAC value, which is a DSP output value in the present invention, may be an optical output value at which the compensation is made or an optical output value before compensation is made, which may be selected by a user.

The laser diode LD emits light having a recording power corresponding to the recording control level, and the recording power of the emitted light, that is, the current, is detected by the front photodiode FPD. The detected current of light is converted into MDI voltage value and input to the DSP.

As an example, values stored in the DSP are as follows.

        division    FPD output value (first MDI value)       LD light output target value        BD SL (Single)      113.5 mV    432 uw (microwatts)        BD DL (Double)      190.0 mV    850 uw (microwatts)        DVD      138.5 mv    282 uw (microwatts)        CD      152.0 mv    212 uw (microwatts)

As one of the objects of the present invention, it will be described to determine the operation state of the LD based on the LD output value (second MDI) and the pre-stored reference value (first M field).

If the LD fails to output the MDI (second MDI) for the target power (light output target value), the LD is determined as NG.

As another one of the object of the present invention, it will be described to determine the operation tendency of the LD by using the output value (DAC Value).

If the LD satisfies the target power, the propensity of the LD may be determined based on the DAC value (Volt) used at this time. The DAC Value determines the current flowing in the LD through the APC circuit. This current is called Iop, and the light quantity of LD is determined according to this current.

In this case, the criteria for determining the size of the DAC value of each recording medium should be obtained from data provided by each pick-up company and experimental results. If the DAC value is higher than the predetermined upper limit in the closed loop state (LD is delivering the target power), it means that a lot of currents (Iop) flows in the LD, which can shorten the lifespan due to excessive current flow. Can be. On the other hand, if the DAC value is less than the under limit, the LD is sensitive to current (Iop), which means that it is easily deteriorated.

Also, as the optical pickup and the ambient temperature increase, the current Iop required by the LD increases, so the reference DAC value must also increase.

In other words, the optimal LD recording power for recording information should be kept at a constant value for accurate recording. However, the optimum recording power varies greatly depending on the surrounding environment, especially the ambient temperature. In other words, the recording power output from the LD decreases as the ambient temperature increases and increases as the ambient temperature decreases. Therefore, the optical recording / reproducing apparatus supplies a large amount of current to the LD as the temperature increases, and supplies a small amount of the current as the temperature decreases in order to maintain the recording power constant.

FIG. 3 is a diagram of an embodiment 300 for determining the propensity of operation of an LD at the output value (DAC Value) of the DSP of FIG.

As shown in the figure, in the target power (32) in accordance with the propensity of LD, When LD A 31 of BD needs 18 DAC value of 27, LD B 33 of BD, and 36 of LD C 35, Limit (under) near when LD B 33 is normal LD limit (36) / upper limit (37)) and determine the propensity of LD.

That is, as described above, when the DAC value is larger than the predetermined upper limit (that is, in the case of LD C), it means that a large amount of current (Iop) flows in the LD, which is a lifespan because the current can flow excessively. This can be shortened.

On the other hand, if the DAC value is smaller than the under limit (ie, LD A), the LD is sensitive to current (Iop), which means that it is easily deteriorated.

Therefore, the life of the LD may be determined based on the determined operation tendency, and the life of the LD may be controlled by controlling the current input to the LD by the APC.

4 is a diagram 400 illustrating a change of a limit value of a DAC value, which is an output value of the DSP of FIG. 2, according to a temperature.

As shown in the figure, when the optical device, the optical pickup, the LD itself, and / or the ambient temperature rises, the DAC value increases.

That is, it can be seen that as the temperature increases, the DAC value increases as the DAC value 41 at 25 degrees, the DAC value 42 at 50 degrees, and the DAC value 43 at 80 degrees.

5 is a maximum value of a target light output value (Target power) for each recording medium, a first MDI value (Table 1) for the target light output, and an output value (DAC value) by the measured light output value (second MDI) of the light source. (Upper limit) or the value of the under (under limit) is a flow chart 500 for determining the operation state and the propensity of operation of the light source through the setting and comparison.

The DAC value may be a value at which compensation is performed or no compensation is performed on the second MDI value, which is controlled based on a user's selection.

As shown in the figure, the target light output value (Target power) for each recording medium / the light output value (first MDI) of the light source for the target output value and the output value (DAC Value) by the MDI (second MDI) used Set the value of the maximum value (Upper limit) or the minimum value (under limit) and save it in the DSP or memory. (S 501).

As shown in FIG. 1 and FIG. 2, the light source LD configured in the optical pick-up is turned on. (S 503).

As shown in FIG. 2, the output of the LD is compared with the MDI value (second MDI) measured by the FPD and the first stored MDI value for setting target power (see Table 1). (S 505).

As a result of the comparison, when the second MDI value is smaller than the first MDI for generating target power, the current operating state of the LD is determined to be NG. (S 507, S 511).

Meanwhile, as a result of the comparison, when the second MDI value is not smaller than the first MDI for generating target power, the current operation state of the LD is GOOD, and in order to determine the operation tendency of the LD, the second Check whether the DAC value, the DSP output value of the MDI value, exists in the upper limit / under limit range (S509).

As a result of the check, when the DAC value is present in the upper limit / under limit range, it can be seen that the LD operates normally for a period of time according to the specification. However, if the DAC value is not within the upper limit / under limit range, the LD does not operate normally. Therefore, adjust the current input to the LD currently in use or LD currently in use. You will find that you need to replace it sooner than the replacement or the specification period.

In other words, the operation tendency of the light source is compared with the output value (DAC Value) and the maximum value (Upper limit / Under limit) of the used light source, and the propensity of LD (light current) as the light source may be shortened and the lifespan may be shortened. Whether or not deterioration is possible, and the input current of the light source can be controlled, replaced or predicted for life.

As shown in FIG. 4, the upper limit / under limit range is set to vary with temperature.

As described above, the present invention is to measure the optical power value output from the light source, for example LD (Laser Diode) through the Front Photo Diode (FPD), the measured optical power value (second MDI ) Can determine whether the LD satisfies the first MDI value for the predetermined target power value (if not small) and confirms the operation state of the LD.

Further, when the output / used optical power value (second MDI) satisfies a first MDI value for generating a predetermined target power value, the DSP output value of the second MDI value used in the light source The operation tendency of the LD can be determined by comparing the (DAC Value) with a predetermined upper limit / under limit.

For example, when the DSP output value (DAC Value) is larger than a predetermined upper limit, it indicates that the current input to the light source is too large, which may predict that the lifetime of the LD may be shortened or the current input to the LD. Control (at least to be output less than the Upper Limit) can extend the life of the LD.

On the other hand, when the DSP output value (DAC Value) is smaller than a predetermined under limit, it indicates that the LD is likely to deteriorate in response to the current inputted to the light source, thereby controlling the current inputted to the LD (at least). Output greater than the Under Limit).

Therefore, based on the output optical power of the light source, if the current state (NG, GOOD) of the LD can be confirmed, and if the output value of the LD (second MDI) satisfies the first MDI for a predetermined target power value, That is, when the current LD state is GOOD, the preliminary upper limit / under limit range of the used DAC value is checked to determine the propensity of LD (the possibility of shortening the life and deterioration possibility) of LD as a light source. Input current can be controlled.

The foregoing has been described with reference to the preferred embodiments of the present invention, and those skilled in the art to which the present invention pertains, within the essential technical scope of the present invention and other forms of the detailed description of the present invention Embodiments of may be implemented. Here, the essential technical scope of the present invention is shown in the claims, and all differences within the equivalent range will be construed as being included in the present invention.

The present invention can determine the operation state and the propensity of the LD by checking the output of the LD, thereby determining whether the LD can be used, determining replacement time, and controlling input current for further use.

In addition, it is possible to effectively determine the operation tendency of LD by variably setting the operation determination criteria of LD according to the temperature condition.

Claims (16)

An optical apparatus in which at least one operation of recording / reproducing data on an optical medium is performed, An optical pickup unit including a light source for emitting output light corresponding to each optical medium; And At least one predetermined light output target value for each optical medium, an output value for the target value, a maximum value or a minimum value for determining the operation of the light source, and an output value of the light source are compared to control the current input to the light source. And a controller configured to determine at least one operation state or operation tendency of the light source. The light source control apparatus according to claim 1, wherein the optical pickup section further comprises means for measuring the light output of the light source. The light source control apparatus according to claim 2, wherein the light source is a laser diode (LD), and the means for measuring the light output of the light source is a front photo diode (FPD). The light source control apparatus according to claim 1, wherein the upper limit or the lower limit of the light output value is not smaller than an output value for a predetermined light output target value. 5. The light source control apparatus according to claim 1 or 4, wherein an upper limit or an under limit of the light output value is variable based on the ambient temperature. According to claim 1, APC (Auto Control) to control the current input to the light source on the basis of the comparison result of the light output value (DAC Value) by the output value (MDI) of the used light source (Upper / under Limit) And a power control device. The light source control apparatus according to claim 1 or 6, further comprising a DSP unit for processing the measured output value MDI of the light source and contacting the APC. 8. The method of claim 7, wherein the unit of the measured light output MDI and the DSP output value DAC VALUE is V (voltage), and the APC output value inputted to the light source based on the comparison result is I (current). Light source control device, characterized in that. Setting at least one target light output value for each recording medium, an output value for the target light output, and a maximum value or minimum value for determining the operation of the light source; Comparing the output value of the measured light source with the output value for the set target light output value; And And determining an operating state of the light source based on the comparison result. The light source control method of claim 9, further comprising: determining an operation tendency of the light source by comparing the output value according to the measured / used light output value with the set maximum value / minimum value. The method of claim 10, further comprising controlling a current input to the light source based on the comparison result. 10. The method of claim 9, wherein the operating state of the light source is compared with the output value of the measured light source and the output value for the target light output value, characterized in that including the NG and GOOD state. 11. The method of claim 10, wherein the operation propensity of the light source is compared to the output value of the light source used and the maximum value (Upper limit / minimum limit) to determine the propensity of LD as a light source, thereby controlling the input current of the light source Light source control method characterized in that. 12. The light source control method according to claim 11, wherein when the temperature of the optical device increases, the output value of the light source is decreased, so that the current input to the light source is increased. 12. The light source control method according to claim 11, wherein when the temperature of the optical device decreases, the output value of the light source is increased, thereby reducing the current input to the light source. The light source control method according to claim 14, wherein the reference DAC value also increases when the temperature of the optical device increases.
KR1020090035937A 2009-04-24 2009-04-24 Apparatus and method for controlling an optical source KR20100117279A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2022075798A1 (en) * 2020-10-08 2022-04-14 엘지이노텍 주식회사 Light driving apparatus and method for driving same

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2022075798A1 (en) * 2020-10-08 2022-04-14 엘지이노텍 주식회사 Light driving apparatus and method for driving same

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