JP2003296952A - Focus balance automatic adjustment apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a focus balance automatic adjustment apparatus capable of automatically adjusting a balanced value of a focus error signal. <P>SOLUTION: The focus balance automatic adjustment apparatus is provided with: an RF signal detection means 6 for detecting the presence/absence of an RF signal obtained from an output of an optical pickup, which collects a light beam, forms a light spot on a recording and reproducing face of an optical disk and detects its reflected light; a microprocessor 11 for reading information of the presence/absence of the RF signal at each position of the optical pickup from the RF signal detection means; and an adjustment means 7 for adjusting a balanced amount of a focus error signal: The focus balance automatic adjustment apparatus discriminates that it is possible to adjust the balanced amount of the focus error signal when the means 6 detects the RF signal at a position of the optical pickup on the basis of the information indicative of the presence/absence of the RF signal read by the microprocessor to start the adjustment means thereby adjusting the balanced amount of the focus error signal at the position of the optical pickup. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention automatically adjusts the balance amount of a focus error signal in an apparatus for recording or reproducing information on an optical disk or a magneto-optical disk such as a CD-R or a mini disk (hereinafter referred to as MD). Device for adjusting manually.

[0002]

2. Description of the Related Art Conventionally, compact discs (hereinafter referred to as "optical discs" for recording acoustic information and various data)
(Abbreviated as CD) has been used. However, in recent years, information-recordable optical discs such as CD-R and MD have become widespread as recordable optical discs having a reproduction time equivalent to that of CDs.

In the MD, information is written by a magnetic field modulation overwrite method, and the laser power of the light beam is increased to raise the temperature on the surface of the disk to the Curie temperature, while the optical disk is irradiated with the light beam. Information is recorded by applying magnetic fields of N and S poles to the magnetic film portion with a magnetic head. On the other hand, at the time of reproduction, when the recording surface is irradiated with the light beam as described above, the magnetic Kerr effect occurs in the magnetic film of the optical disc, and the polarization plane of the return light is in the positive or reverse direction corresponding to N / S. Turn slightly to. Two light receiving elements are provided in the optical pickup, which detects the return light due to this slight deflection angle,
An RF signal is created by creating a sum signal or a difference signal of the outputs of the two light receiving elements by the RFIC.

Further, it is known that a conventional disc recording / reproducing apparatus is provided with an RF signal presence / absence detecting means for detecting the presence / absence of an RF signal, as shown in FIG.
In FIG. 8, reference numeral 1 is an optical disk having a predetermined track shape, and 2 is a rotating means for rotating the optical disk 1. Three
Is an optical pickup, which collects a light beam on the recording / reproducing surface of the optical disc 1 to form a light spot, and detects the reflected light. Reference numeral 4 is an RF signal generation means for generating an RF signal from the output of the optical pickup 3, 5 is an RF signal detection means for detecting the output signal of the RF signal generation means 4, and 6 is an RF signal presence / absence detection means for detecting the presence or absence of the RF signal. , 7 are focus balance adjusting means for adjusting the balance amount of the focus error signal. Reference numeral 8 denotes a focus balance switching means, which switches the amplification factor of a predetermined output for detecting the focus position of the optical pickup 3. Reference numeral 9 denotes a focus error signal generating means, which generates an error signal for the focus position of the light spot from the output of the focus balance switching means 8. Reference numeral 10 denotes a focus control unit, which receives the focus error signal generated by the focus error signal generation unit 9 and performs focus control. Reference numeral 11 denotes a microprocessor, which activates the focus balance adjusting means 7 and applies a disturbance signal of a predetermined amplitude and frequency to the focus error signal generating means 9 to operate it, and activates the focus control means 10 by the output thereof. The pickup 3 is vibrated in the focus direction. The focus balance adjusting means 7 is
The focus balance adjustment value is determined so that the RF signal becomes maximum, and the gain of the focus balance switching means 8 is switched.

The RF signal presence / absence detecting means 6 is provided in the above structure for the following purpose. That is, if there is a scratch or dust on the recording / reproducing surface of the disc, the RF signal may be lost when the spot of the optical pickup 3 passes through the position. At that time, it is necessary to hold the output of each circuit block so that the data slice circuit, the PLL circuit, the servo control circuit, and the like do not run away. The output of the RF signal presence / absence detecting means 6 is used for that purpose, and was used in the internal processing of the DSP or the like. Therefore, the conventional device cannot detect the presence or absence of the RF signal at the current pickup position from the outside.

There are a plurality of types of MDs, but in a pre-mastered disc for reproduction only in which music contents are recorded in advance, RF is spread over the entire information area.
Since the signal exists, the balance of the focus error signal is adjusted every time the disc is reproduced. However, in the case of a recordable magneto-optical disk, the RF signal does not always exist anywhere in the entire information area, and there is a missing portion of the RF signal. Therefore, in the conventional product shipping process, JP-A-8-321049 discloses. The balance value of the groove area in which the recording / reproducing information is recorded is determined based on the result of the balance adjustment of the focus error signal by the pit area using the automatic focus balance adjusting device as shown in FIG.

[0007]

However, in the conventional adjustment of the balance voltage as described above, since the adjustment is performed by using the reference disk dedicated to the adjustment in the shipping process, this reference disk and the user actually use it. The balance value adjusted at the process shipping stage may actually be changed due to differences in the characteristics of the discs used, changes in characteristics due to aging deterioration of the pickup, or changes in the playback environment due to the temperature when the user actually uses it. It may be inappropriate as the balance value in the state used by the user. Therefore, it is not possible to focus at the optimum focus point, and S /
There is a problem in that N is deteriorated and jitter is deteriorated, so that an accurate RF signal cannot be reproduced.

In order to solve such a problem, it has been considered to equip the MD recording / reproducing apparatus with the focus balance automatic adjusting device so as to adjust the focus balance for each individual disc.

However, in a recordable MD, when the address information or the like cannot be read due to the influence of dust or scratches on the recording surface, the information is written by skipping the location, and as described above, There is a missing part. Since the RF signal cannot be obtained at this missing portion, the focus balance adjustment as described above cannot be properly performed.

Therefore, the present invention solves the above problems,
An object of the present invention is to provide a focus balance automatic adjustment device capable of automatically adjusting the balance value of a focus error signal.

[0011]

In order to solve the above-mentioned problems, an automatic focus balance adjusting apparatus of the present invention condenses a light beam to form a light spot on the recording / reproducing surface of an optical disc and detects its reflected light. For detecting the presence / absence of an RF signal obtained from the output of the optical pickup, a microprocessor for reading the presence / absence of the RF signal at each position of the optical pickup from the RF signal presence / absence detecting means, and a focus. Adjusting means for adjusting the balance amount of the error signal. Based on the information on the presence or absence of the RF signal read by the microprocessor,
When the RF signal is detected at the position of the optical pickup, it is determined that the balance amount of the focus error signal can be adjusted, the adjustment means is activated, and the balance amount of the focus error signal at the position of the optical pickup is activated. Adjust.

Preferably, when the RF signal cannot be detected at the position of the optical pickup, the reproduction is continued with the focus servo, the tracking servo, and the spindle servo applied, and the focus error occurs at the time when the RF signal is out of the missing position. The configuration is such that signal balance adjustment is performed.

Further preferably, when an RF signal is not detected at a position of the optical pickup for a certain period of time,
The information recording medium further includes a moving unit that moves the optical pickup to an area where the table information indicating the relationship between the recording information and the recording position is written. In this configuration, it is preferable to adjust the balance amount of the focus error signal when an RF signal can be detected after moving to the area where the table of contents information is written by the moving means.

Further, preferably, the RF signal presence / absence detecting means includes a register for storing a detection result of the RF signal, and an MP.
By incorporating a U interface circuit, the presence or absence of an RF signal can be read from the microprocessor.

Alternatively, the RF signal presence / absence detecting means is R
By having the function of outputting the detection result of the presence or absence of the F signal, the presence or absence of the RF signal can be determined.

It is preferable that the focus balance automatic adjusting device having any one of the above-mentioned configurations is built in the disc recording / reproducing device or the disc reproducing device.

[0017]

1 is a block diagram showing the configuration of a focus balance automatic adjusting apparatus according to an embodiment of the present invention. Reference numeral 1 is an optical disk having a predetermined track shape, and 2 is a rotating means for rotating the optical disk 1.
An optical pickup 3 collects a light beam on the recording / reproducing surface of the optical disc 1 to form a light spot, and detects the reflected light. Reference numeral 4 is an RF signal generating means for generating an RF signal from the output of the optical pickup 3, and 5 is an RF signal generating means 4.
Is an RF signal detecting means for detecting the output signal of, an RF signal presence / absence detecting means for detecting the presence / absence of an RF signal, and a focus balance adjusting means for adjusting the balance amount of the focus error signal. Reference numeral 8 denotes a focus balance switching means, which switches the amplification factor of a predetermined output for detecting the focus position of the optical pickup 3. Reference numeral 9 denotes a focus error signal generating means, which generates an error signal for the focus position of the light spot from the output of the focus balance switching means 8. Reference numeral 10 denotes a focus control unit, which receives the focus error signal generated by the focus error signal generation unit 9 and performs focus control. Reference numeral 11 denotes a microprocessor (hereinafter referred to as MPU), and RF signal presence / absence detection means 6
Based on the output result of, the focus balance adjusting unit 7 is controlled whether or not to execute the focus balance adjustment at the current position of the optical pickup 3.

Regarding the operation of the focus balance adjusting device in the device of the present embodiment configured as described above,
This will be described below.

To perform the focus balance adjustment, the MPU 11 activates the focus balance adjusting means 7 in the states of the focus control ON, the tracking control ON, and the spindle rotation control ON, and the focus error signal generating means 9
A disturbance signal having a predetermined amplitude and frequency is applied to operate the focus control means 10 by its output,
The optical pickup 3 is vibrated in the focus direction. The focus balance adjustment means 7 determines the focus balance adjustment value so that the RF signal becomes maximum, and switches the gain of the focus balance switching means 8. Since the focus balance adjustment is performed so that the RF signal becomes maximum, it is naturally necessary to perform the adjustment at the position on the optical disc 1 where the RF signal is detected. In the pre-mastered MD, there is no problem because the RF signal exists over the entire information area as described above, but the recordable M
In D, if no data is recorded,
As described above, a missing portion of the information recording data may occur, so that the RF signal is not always present.

Therefore, in the present embodiment, the adjustment operation is performed according to the presence or absence of the RF signal at the current position of the optical pickup 3 so that the focus balance adjustment can be automatically performed regardless of the type of MD used. Be configured. Therefore, the MPU 11 is configured to be able to read the output of the presence / absence detection of the RF signal by the RF signal presence / absence detection unit conventionally provided in the optical recording / reproducing apparatus from the outside.

FIG. 2 is a block diagram showing a first specific structural example of the RF signal presence / absence detecting means 6 of FIG. In FIG. 2, reference numeral 12 is a subtractor, which takes a difference between a peak signal and a bottom signal, which are envelope signals on the bright side / dark side of the RF signal detected by the RF signal detecting means 5. 13 is a comparator,
A value obtained by multiplying the signal level obtained from the difference between the peak signal and the bottom signal created by the subtractor 12 by a predetermined value is compared with the amplitude of the RF signal currently being reproduced. 14 is a comparator 13
It is a register for storing the comparison result and the detection result of the RF signal. Reference numeral 15 is an MPU interface circuit that interfaces with the MPU 11.

The operation of this RF detection presence / absence detection means is as follows. First, the subtracter 12 takes the difference between the peak signal and the bottom signal from the peak / bottom detection results, and if this signal level is A, then a comparison is made when performing RF signal detection by slice level = A × predetermined multiple. A slice level that is a value (hereinafter referred to as "NRFDET slice level") is obtained. The specific value of the predetermined multiple is
Since it varies depending on various conditions, the present embodiment is configured to be variable.

For this series of operations, a recordable disc reference disc is used at the time of process shipment adjustment, and R
The NRFDET slice level is learned while the F signal is being detected. Thus, when the user's disc is inserted after shipment, if the reproduced RF signal has an amplitude larger than this slice level, it is determined that there is an RF signal. The detection result of the presence or absence of the RF signal is registered in the register 14
It is also output to the focus balance adjusting means 7. The register 14 stores the detection result of the presence or absence of the RF signal. In the focus balance adjusting means 7,
The balance amount during focus balance adjustment is calculated only while the RF signal is being detected. In addition, the register 14
In response to the read request from the MPU 11,
Like the focus lock signal and the tracking lock signal, the detection result of the RF signal can be read as a servo status signal via the MPU interface circuit 15.

FIG. 3 is a block diagram showing a second specific structural example of the RF signal presence / absence detecting means 6 of FIG. In FIG. 3, the operations of the subtractor 12 and the comparator 13 are the same as in FIG. In the configuration of FIG. 3, the detection result of the presence or absence of the RF signal from the comparator 13, which is output to the focus balance adjusting means 7, is directly input to the input of the MPU 11.

FIG. 4 is a flow chart showing a case where the reproduction operation is performed after the focus balance adjustment is performed according to the type of MD used in the embodiment of the present invention, which is shown in each step of F1 to F20. .

As shown in FIG. 4, when a reproduction request is received (step F1), it is determined whether the inserted disc is for reproduction only, that is, whether it is a premastered MD or a recordable MD (F2). The type of MD can be discriminated by a disc type discriminating hole provided in the disc cartridge, and there is also a method of utilizing the reflectance of the disc, but the explanation is omitted because it is not directly related to the present invention. To do. If it is determined that the disc is a read-only disc, that is, a pre-mastered MD, the servo control is activated (F3), the focus system,
Executes servo control of tracking system and spindle system.

Next, the MPU 11 judges whether or not the RF signal can be detected by the RF signal presence / absence detecting means 6 (F
4). Since it is a primastar's MD, it should be able to be detected most of the time.
The presence or absence of a signal is detected. If the RF signal can be detected,
Focus balance adjustment is executed (F5). As a method for adjusting the focus balance, for example, Japanese Patent Laid-Open No. 8-32
The adjustment method disclosed in Japanese Patent No. 1049 can be used. When the inserted MD is a premastered MD, as shown in FIG. 5A, since data is continuously recorded and an RF signal exists, focus balance adjustment can be performed. . FIG. 5 shows the recording area of the optical disc as a band-shaped diagram, in which the track number is shown in the area where the music information is recorded and the area where the music information is not recorded is shaded. After performing focus balance adjustment, the TO of pre-mastered MD
The C information is read (F6) and the reproducing operation is performed (F2
0).

If it is determined in step F2 that the disc is not a read-only disc, that is, a recordable MD is inserted, servo control is activated (F7) as in the case of premastered MD, and each servo is activated. In the state in which the
The MPU 11 determines whether the F signal is detected (F9). In the case of the recordable MD, there is a case where the RF signal is continuously lost as described above, so a time-out is provided (F8). Regarding the time-out time setting, it may be set appropriately in accordance with the system to which the present invention is applied, in consideration of the time required for starting the reproduction. As shown in FIG. 5B, when the RF signal can be detected in the vicinity of the current position of the optical pickup 3 without loss of the RF signal, focus balance adjustment is performed (F1).
0). After the focus balance adjustment is executed, the UTOC information is read (F11) and the reproducing operation is performed (F20). Further, as shown in FIG. 5C, even if the RF signal is missing at the current position of the optical pickup 3, if the RF signal can be detected within the time set by the timeout, the focus balance adjustment is executed. (F10). If, during execution of focus balance adjustment, the RF signal is missing for a short period even if it passes through the RF signal missing part,
There is no problem because the focus balance adjustment means 7 suspends the execution of the focus balance adjustment. Also,
If the period in which the RF signal is missing is long, there is no problem because the focus balance adjusting means itself has a time-out, and it is sufficient to move to the UTOC area and perform focus balance adjustment there as described later.

Next, when the time-out occurs in step F8, the optical pickup 3 is forcibly moved to the UTOC area (F12), and it is checked whether the RF signal presence / absence detecting means 6 detects the RF signal. , MPU1
1 determines (F14). When the RF signal can be detected, focus balance adjustment is executed (F15). Here as well, a timeout (F13) is provided as in the above case.
After the focus balance adjustment is performed, the UTOC information is read (F16) and the reproducing operation is performed (F20). Where U
The reason why the optical pickup is moved to the TOC area is that, for example, in the case of a disc that has been recorded once and then all erased,
This is because even if the UTOC area is viewed, it cannot be known where the recorded area is. Further, even if all erased, an RF signal always exists in the UTOC area in the disc once recorded. In this way, according to the present invention, focus balance adjustment can be performed before recording even on an all-erased disc, and stable recording operation is possible.

Next, when the time is out in step F13, the UTOC information is read (F1
7), it is discriminated as a virgin disc (F18). Since it is determined that the disc is a virgin disc, the reproduction is stopped and the reproduction is stopped (F19).

As described above, according to the present embodiment, the focus balance is automatically adjusted for each disc to be used, even for a recordable MD having a missing portion where information is not recorded. Because you can
Differences in the characteristics of the disk actually used by the user,
Even if the characteristics of the pickup change due to aging, or the playback environment changes due to the temperature actually used by the user, an accurate focus error signal corresponding to the RF signal can be obtained, and accurate focus servo control is possible. It can be performed. As a result, it is possible to perform information reproduction with a good S / N ratio and high reproduction quality.

In the above-described embodiment, an example in which the focus balance adjustment is executed at the time of reproducing information has been described, but the present invention is not limited to this, and the focus balance adjustment is similarly performed at the time of recording. It is possible to At the time of recording, music information may not be recorded at all in the recordable MD, but in this case, focus balance adjustment may be performed in the TOC area of the lead-in area. This is because the information about the disc is written in the TOC area by the pits, so that the RF signal exists. When recording in the groove area, recording may be performed using a balance value obtained by offsetting a predetermined value in accordance with the characteristics of the pickup from the focus balance adjustment result in the TOC area. As described above, the present invention can be applied not only to the reproduction-only device but also to the recording / reproducing device.

Further, in the above-described embodiment, the focus balance adjustment can be performed in a series of various automatic adjustments such as tracking gain adjustment and balance adjustment, and the focus balance adjustment can be performed before the TOC information and the UTOC information are read. RF can be done within the time-out
When the signal can be detected, the start-up time can be shortened and the reproducing operation can be started in a time comparable to that of the conventional device.

FIG. 6 is a block diagram showing the configuration of a disk recording / reproducing apparatus incorporating the focus balance automatic adjusting apparatus of the present invention. FIG. 7 is a block diagram showing the configuration of a disc reproducing apparatus incorporating the focus balance automatic adjusting apparatus of the present invention. Like these devices, by incorporating the focus balance automatic adjusting device of the present invention,
It is possible to adjust the balance amount of the focus error signal before the disc reproduction and the recording, so that the stable disc reproducing operation and recording operation can be performed.

In the embodiment described above, the case where the MD is used as an example of the information recording medium has been described, but the present invention is not limited to this, and the recordable CD-R can be used as the information recording medium. , Rewritable C
It is also applicable when using D-RW or the like.

[0036]

According to the present invention, the microprocessor reads the presence / absence of the RF signal at each position of the optical pickup from the RF signal presence / absence detecting means for detecting the presence / absence of the RF signal obtained from the output of the optical pickup, Since it is possible to determine whether or not the balance amount of the focus error signal can be adjusted at the position of the pickup based on the presence or absence of the information reproduction signal, even when an information recording medium having a missing information portion is used, Focus balance adjustment can be automatically and favorably performed for each individual information recording medium.

[Brief description of drawings]

FIG. 1 is a block diagram of a focus balance automatic adjustment device according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration example of an RF signal presence / absence detecting unit.

FIG. 3 is a block diagram showing another configuration example of the RF signal presence / absence detection unit.

FIG. 4 is a flowchart showing processing in the focus balance automatic adjustment apparatus of FIG.

FIG. 5 shows the relationship between the position of the optical pickup in the MD recording / reproducing apparatus and the missing data portion on the MD,
(A) In the case of pre-mastered MD, (B)-(D) is a figure which shows the case of recordable MD

FIG. 6 is a schematic diagram showing a disc recording / reproducing device having a focus balance automatic adjusting device according to the present invention built therein.

FIG. 7 is a schematic view showing a disc reproducing device having a built-in focus balance automatic adjusting device according to the present invention.

FIG. 8 is a block diagram showing a conventional focus balance automatic adjustment apparatus.

[Explanation of symbols]

1 optical disc 2 rotation means 3 optical pickup 4 RF signal generation means 5 RF signal detection means 6 RF signal presence / absence detection means 7 Focus balance adjustment means 8 Focus balance switching means 9 Focus error signal generation means 10 Focus control means 11 Microprocessor (MPU) 12 Subtractor 13 Comparator 14 registers 15 MPU interface circuit 16 Disc recording / reproducing means 17 Disc playback means

Claims (7)

[Claims] 1. An RF signal presence / absence detecting means for detecting the presence / absence of an RF signal obtained from an output of an optical pickup for collecting a light beam to form a light spot on a recording / reproducing surface of an optical disc and detecting a reflected light thereof. And a microprocessor for reading information on the presence / absence of an RF signal at each position of the optical pickup from the RF signal presence / absence detecting means, and an adjusting means for adjusting the balance amount of the focus error signal, and the RF read by the microprocessor. Based on the information about the presence / absence of a signal, it is determined that the balance amount of the focus error signal can be adjusted when the RF signal is detected at the position of the optical pickup, and the adjusting means is activated to activate the adjusting means. A focus balun characterized by adjusting the balance amount of the focus error signal at the position Automatic adjustment device. 2. RF at the position of the optical pickup
When the signal cannot be detected, the reproduction is continued with the focus servo, the tracking servo, and the spindle servo applied, and the balance of the focus error signal is adjusted at the time when it is out of the missing position of the RF signal. The automatic focus balance adjustment device described in 1. 3. When the RF signal is not detected at the position of the optical pickup for a certain period of time or more, the optical pickup is moved to an area on the information recording medium in which table information indicating the relationship between the recording information and the recording position is written. The automatic focus balance adjusting apparatus according to claim 1, further comprising a moving unit. 4. The focus according to claim 3, wherein when an RF signal can be detected after moving to the area where the table of contents information is written by the moving means, the balance amount of the focus error signal is adjusted there. Balance automatic adjustment device. 5. The RF signal presence / absence detecting means is configured to read the presence / absence of an RF signal from the microprocessor by incorporating a register for storing the detection result of the RF signal and an MPU interface circuit. The automatic focus balance adjusting apparatus according to claim 1, wherein 6. The RF signal presence / absence detecting means has a function of outputting a detection result of the presence / absence of an RF signal, whereby R
The automatic focus balance adjusting apparatus according to claim 1, wherein the focus balance automatic adjusting apparatus is configured to be able to determine the presence or absence of an F signal. 7. A disc recording / reproducing device or a disc reproducing device, comprising the focus balance automatic adjusting device according to claim 1.