JP3938678B2 - Optical disk device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical disc apparatus. More specifically, when the light beam spot formed by the optical head is located in the barcode area, the optical head moves so that the light beam spot moves toward the control data area radially adjacent to the barcode area. The present invention relates to an optical disc apparatus that controls
[0002]
[Prior art]
An optical disk with a barcode is known as a read-only information recording medium with a barcode (hereinafter referred to as a ROM with a barcode). An optical disk with a barcode can reproduce data recorded therein.
[0003]
An optical disc with a barcode generally includes a user data area, a control data area provided on the inner circumference side of the user data area, and a barcode area provided on the further inner circumference side of the control data area.
[0004]
User data is recorded in the user data area. The user data is, for example, music data reproduced by the optical disc apparatus based on an instruction from the user and file data used in the computer. Control data is recorded in the control data area. The control data is information relating to the physical characteristics of the barcode-added ROM, such as the capacity and type of the barcode-added ROM. In the barcode area, barcode data is recorded by barcode. The barcode data is, for example, data for preventing unauthorized copying and / or data relating to a manufacturing serial number. Bar code data is recorded in the form of a bar code, unlike user data and control data. The barcode is obtained by optically processing an optical disk, and is formed by removing a part of the reflection film or directly printing ink. One method of forming a barcode in the barcode area is a method of forming a barcode by partially removing a part of a reflective film on a recording surface of an optical disk using a technique such as laser cutting. .
[0005]
Since the barcode data is recorded in a format different from that of the control data and user data, means for reproducing the barcode data must be different from the means for reproducing the control data and user data.
[0006]
As an example of a barcode-added ROM, Japanese Patent Laid-Open No. 10-97771 discloses a barcode-added optical disc including a user data area, a control data area, and a barcode area.
[0007]
FIG. 17 shows the structure of a barcode-added optical disk 1700 that is a barcode-added ROM. 17A is a plan view of the optical disc 1700 with barcode, and FIG. 17B is a barcode region 1710, control data region 1720, user data region 1730, and ROM region of the optical disc 1700 with barcode. The positional relationship with 1740 is shown in a sectional view of the optical disc 1700 with a barcode.
[0008]
As shown in FIGS. 17A and 17B, the barcode 1750 is formed on the inner peripheral portion of the optical disc 1700 with barcode. Bar code 1750 is formed in bar code area 1710. A control data area 1720 is provided on the outer peripheral side of the bar code area 1710 where the bar code 1750 is formed, and a user data area 1730 is provided further on the outer peripheral side of the control data area 1720. The ROM area 1740 includes a part of the barcode area 1710, a control data area 1720, and a user data area 1730. In the optical disc with barcode 1700, the barcode area 1710 is adjacent to the control data area 1720 in the radial direction, and the control data area 1720 is adjacent to the user data area 1730 in the radial direction.
[0009]
In FIG. 17B, R1 indicates the length in the radial direction from the center of the optical disc 1700 with barcode to the innermost circumference of the barcode area 1710. R2 indicates the length in the radial direction from the center of the optical disc 1700 with barcode to the innermost periphery of the ROM area 1740. R3 indicates the length in the radial direction from the center of the optical disc 1700 with barcode to the innermost periphery of the control data area 1720. R4 indicates the length in the radial direction from the center of the optical disc 1700 with barcode to the innermost periphery of the user data area 1730. R5 indicates the length in the radial direction from the center of the optical disc 1700 with barcode to the outermost periphery of the user data area 1730. When the optical disc 1700 with barcode is a DVD, the lengths in the radial direction of R1, R2, R3, R4, and R5 are 22.3 mm, 22.6 mm, 23.5 mm, 24.0 mm, and 58 mm, respectively.
[0010]
In the barcode area 1710, a different ID for each barcode-added optical disc 1700, the manufacturer, lot, and serial number of the barcode-added optical disc 1700 are displayed. Such data is recorded.
[0011]
In the control data area 1720, physical data (disc type, track pitch, number of layers, etc.) relating to the type and format of the optical disc 1700 is recorded as control data.
[0012]
In the ROM area 1740, pit rows are formed in advance on a plurality of information tracks, and data is recorded as pit rows. However, generally, data is not recorded in an area overlapping the barcode area 1710 in the ROM area 1740. This is because the bar code 1750 is formed after the pit row is formed in the ROM area 1740. Even if data is recorded in an area overlapping the bar code area 1710 in the ROM area 1740, the bar code 1750 This is because the formation of the pit row may be deformed by the formation.
[0013]
In general, an optical disc apparatus includes an optical head and a control unit that controls the optical head. The optical head irradiates the optical disk with barcode with a light beam, thereby forming a light beam spot on the optical disk, and outputs a signal corresponding to the light beam reflected by the optical disk. The optical head can read information (data and address) of a portion where the light beam spot is formed on the optical disc as a signal corresponding to the light beam reflected from the portion.
[0014]
The operation of the conventional optical disc apparatus when accessing the control data area 1720 of the optical disc 1700 with barcode will be described below.
[0015]
The control unit controls the optical head so that the light beam spot formed on the optical disk by the optical head is positioned in the control data area 1720. However, an error may occur in the control of the optical head by the control unit. For example, the control unit may move the light beam spot directly into the control data area 1720 due to a mechanical error of a mechanism for moving the optical head or due to a small area of the control data area 1720. Cannot control the optical head. Therefore, instead of directly positioning the light beam spot in the control data area 1720, the light beam spot is temporarily moved outside the control data area 1720, that is, in the user data area 1730, and then the light beam spot is controlled. Move into the data area 1720. With the light beam spot positioned within the user data area 1730, focus control and tracking control are sequentially performed, and the light beam spot output from the optical head is made to follow the information track of the optical disc 1700 with a barcode. The address indicating the position of is read.
[0016]
If the address indicating the position of the light beam spot can be read, the control unit can control the optical head so that the light beam spot repeats one track jump and moves into the desired control data area 1720. In the barcode-coated optical disc 1700 which is a ROM with a bar code, the user data area 1730 is recorded with information in a pit row in the same way as the control data area 1720. Therefore, a single light beam spot is recorded over different areas. The optical head can be controlled to jump.
[0017]
Here, the light beam spot is moved from the user data area 1730 side to the control data area 1720. This is because the barcode 1750 is formed in the barcode area 1710, so the optical head cannot properly read the address from the barcode area 1710. Therefore, the light beam spot jumps one track. This is because it cannot be controlled.
[0018]
[Problems to be solved by the invention]
The conventional optical disk apparatus assumes the movement of the light beam spot to the control data area 1720 only in the case of the barcode-added ROM as described above.
[0019]
An object of the present invention is to provide an optical disc apparatus suitable for accessing a control data area of a bar code RAM which is a recordable / reproducible information recording medium.
[0020]
Another object of the present invention is to provide an optical disc apparatus that moves a light beam spot from a barcode area toward a control data area.
[0021]
[Means for Solving the Problems]
In general, the control unit controls the optical head based on an address indicating the position of the light beam spot so that the light beam spot repeats one-track jumping and moves to a predetermined address to be read.
[0022]
However, if the optical disc includes a barcode area, the address indicating the position of the light beam spot in the barcode area does not mean an accurate address. Therefore, the control unit does not accurately identify the light beam spot in the barcode area. The optical head cannot be controlled to perform single track jumping.
[0023]
Therefore, when the control unit controls the optical head so that the optical head outputs a signal from the control data region that is adjacent to the barcode region in the radial direction, the control unit ensures that the optical head receives the signal from the control data region. It is necessary to control so that the light beam spot formed by the optical head does not enter at least the barcode area.
[0024]
Accordingly, the present invention provides a user data area in which user data is recorded, a control data area that is provided adjacent to the user data area in the radial direction, and includes at least physical data relating to the type and format of the optical disc, An optical disc that records or reproduces information on an optical disc provided with a bar code area that is provided in the radial direction adjacent to the control data area and in which information unique to the optical disc is formed An optical head that forms a light beam spot on the optical disc by irradiating the optical disc with a light beam, and outputs a signal corresponding to the light beam reflected by the optical disc, and the optical head Depending on the signal output from the optical beam spot, the bar code And determining the bar code area determination section for determining whether or not located in the region, In the user data area, push-pull method is used, and in the control area, phase difference method is used to execute tracking control, A control unit that moves a light beam spot of the optical head to access information at a predetermined address of the optical disc, and the control unit transmits the light beam spot of the optical head to a predetermined data in the control data area. When executing the control to access the address position, if the light beam spot is determined to be located in the barcode area by the barcode area determination unit, the light beam spot moves toward the control data area. The optical head is controlled to move, and an address is detected when it is determined by the barcode area determination unit that the light beam spot is not located in the barcode area.
[0025]
Thereby, for example, when the control error of the optical head by the control unit is large and the light beam spot is located in the barcode area, or the light beam spot located in the control data area is caused by an external impact or the like. Even when moving into the barcode area, the light beam spot can be moved from the barcode area toward the control data area.
[0027]
A control data area determining unit for determining whether or not the light beam spot is located in the control data area; and output from the optical head when it is determined that the light beam spot is located in the control data area And an address detection unit that detects an address indicating the position of the light beam spot in the control data area based on the received signal, the control unit based on the address detected by the address detection unit The movement of the optical head may be controlled.
[0028]
A control data area determining unit that determines whether or not the light beam spot is located in the control data area, the control unit until the light beam spot is determined to be located in the control data area; The control of the optical head may be repeated so that the light beam spot moves toward the control data area.
[0029]
The maximum period among the periods of the signal output from the optical head in accordance with the light beam reflected by the control data area is set as a set period, and the light beam reflected by the barcode area Accordingly, the period of the signal output from the optical head has a period longer than the set period, and the barcode area determination unit detects the maximum period of the signal output from the optical head. A period detector, and a period comparator that compares the maximum period detected by the maximum period detector with the set period to determine whether the light beam spot is located in the barcode area; May be included.
[0030]
When the maximum period detected by the maximum period detection unit is sufficiently larger than the set period, the period comparison unit may determine that the light beam spot is located in the barcode area.
[0031]
The barcode area determination unit includes a maximum cycle detection unit that detects a maximum cycle of a signal output from the optical head, a read clock cycle detection unit that detects a read clock cycle of a signal output from the optical head, The signal is set according to the ratio of the maximum cycle detected by the maximum cycle detector and the read clock cycle detected by the read clock cycle detector and the light beam reflected by the barcode area. A period comparison unit that compares the set clock coefficient with each other and determines whether or not the light beam spot is located in the barcode area.
[0032]
The read clock cycle detector includes a shortest mark length detector that detects a shortest mark length of a signal read from the optical disc, a shortest mark length detected by the shortest mark length detector, and a coefficient of a predetermined shortest mark length. And a read clock cycle deriving unit for deriving a read clock cycle.
[0033]
The barcode area determination unit includes a maximum cycle detection unit that detects a maximum cycle of a signal read from the optical disc, a rotation cycle measurement unit that measures a rotation cycle of the optical disc, and the maximum cycle detection unit that detects the maximum cycle detection unit. A period comparison unit that determines whether or not the light beam spot is located in the barcode area based on a maximum period and the rotation period measured by the rotation period measurement unit may be included.
[0034]
The barcode area determination unit may determine whether or not the light beam spot is located in the barcode area for a predetermined period equal to or more than a time corresponding to 11/12 rotation of the optical disc.
[0035]
The barcode area determination unit compares a smoothing unit that outputs a smoothed signal obtained by smoothing a signal output from the optical head, a time when the smoothing signal changes by a predetermined amount or more, and a predetermined time. And a comparator that determines whether or not the light beam spot is located within the barcode area.
[0036]
The barcode area determination unit includes an amplitude signal generation unit that generates an amplitude signal from a signal output from the optical head, a time when the amplitude signal generated by the amplitude signal generation unit changes by a predetermined amount and a predetermined time And a comparison unit that determines whether or not the light beam spot is located in the barcode area.
[0037]
Bar code data is recorded in the bar code area, and when it is determined that the light beam spot is located in the bar code area, the bar code data is reproduced according to a signal output from the optical head. You may further provide a barcode data reproduction | regeneration part and the barcode data storage part which memorize | stores the reproduced | regenerated barcode data.
[0039]
DETAILED DESCRIPTION OF THE INVENTION
In the following, an optical disc with barcode that is a recordable / reproducible information recording medium with barcode (hereinafter, RAM with barcode) will be considered.
[0040]
FIG. 1 is a schematic diagram of an optical disc 100 with a barcode which is a RAM with a barcode according to the present invention. 1A is a plan view of the optical disc 100 with barcode, and FIG. 1B is a barcode area 110, a control data area 120, a user data area 130, and a ROM area of the optical disc 100 with barcode. The positional relationship between 140 and the RAM area 145 in which data can be recorded once or a plurality of times is shown in a sectional view of the optical disc 100 with a barcode.
[0041]
As shown in FIGS. 1A and 1B, the barcode 150 is formed on the inner peripheral portion of the optical disc 100 with a barcode. The barcode 150 is formed in the barcode area 110. A control data area 120 is provided on the outer peripheral side of the bar code area 110 where the bar code 150 is formed, and a user data area 130 is provided further on the outer peripheral side of the control data area 120. The ROM area 140 includes a part of the barcode area 110 and the control data area 120. The RAM area 145 is a user data area 130. In the optical disk with barcode 100, the barcode area 110 is adjacent to the control data area 120 in the radial direction, and the control data area 120 is adjacent to the user data area 130 in the radial direction.
[0042]
In FIG. 1B, R <b> 1 indicates the length in the radial direction from the center of the optical disc 100 with barcode to the innermost circumference of the barcode area 110. R2 indicates the length in the radial direction from the center of the optical disc 100 with barcode to the innermost circumference of the ROM area 140. R3 indicates the length in the radial direction from the center of the optical disc 100 with barcode to the innermost periphery of the control data area 120. R4 indicates the length in the radial direction from the center of the optical disc 100 with a barcode to the innermost periphery of the user data area 130. R5 indicates the length in the radial direction from the center of the optical disc with barcode 100 to the outermost periphery of the user data area 130. When the barcode-added optical disc 100 is a DVD, the lengths of R1, R2, R3, R4, and R5 in the radial direction are 22.3 mm, 22.6 mm, 23.5 mm, 24.0 mm, and 58 mm, respectively.
[0043]
In the optical disc 100 with barcode, the user data area 130 is a RAM area 145, and the ROM area 140 is a bar shown in FIG. 17 except that it includes a part of the barcode area 110 and a control data area 120. This is the same as the optical disc 1700 with a code. The optical head of the optical disc apparatus can record user data in the RAM area 145 or read the user data from the RAM area 145 based on an instruction from the user.
[0044]
In general, the RAM area 145 records data in a shape different from that of the ROM area 140.
[0045]
Since data that does not need to be overwritten is recorded in the ROM area 140, the data is recorded simultaneously with the formation of the substrate by the phase pit train. FIG. 2 shows how the pits 220 are formed on the information track 210 in the ROM area 140. The ROM area 140 of the optical disk with barcode 100 is formed by embossing in the same manner as the ROM area 1740 of the optical disk with barcode 1700. If the address of the optical disk where the light beam spot formed by the optical head is located can be read in the ROM area, the light beam spot is moved by jumping one track in the optical disk inner circumferential direction or optical disk outer circumferential direction. Can be made.
[0046]
On the other hand, since data with a high possibility of being overwritten is recorded in the RAM area 145, the data is recorded in the form of recording marks on the recording film formed on the groove.
[0047]
For a given RAM, a barcode-added RAM can be manufactured by forming a barcode in the same manner as a barcode is formed in a barcode-added ROM.
[0048]
Hereinafter, as described above with reference to FIG. 17, the operation of the conventional optical disk apparatus accessing the control data area 1720 of the barcode-added ROM is the control data area 120 of the barcode-added optical disk 100 which is the barcode-added RAM. The case where it is simply applied to the operation of accessing is described for comparison. When an operation performed by a conventional optical disc apparatus using a barcode-added ROM is simply applied to the barcode-added RAM, the following problems occur.
[0049]
(1) As described above, in the barcode-added optical disc 100, the control data area 120 and the user data area 130 have different area shapes and data recording methods. Accordingly, in the user data area 130, a push-pull tracking error signal is used as a tracking error signal for controlling tracking, whereas in the control data area 120, a phase difference tracking error signal is used as a tracking error signal. As described above, the control data area 120 and the user data area 130 have different tracking error signals to be used, and therefore, the control data area 120 and the user data area 130 are overrun by a seek or the like, and the light beam spot is different (from the user data area 130 to the control data area 120. Alternatively, when moving from the control data area 120 to the user data area 130), the tracking control becomes unstable and the tracking control may be lost.
[0050]
(2) In the optical disc 100 with barcode, the user data area 130 located on the outer periphery of the control data area 120 is a RAM area 145. When comparing the optical disk with barcode 100 and the optical disk with barcode 1700, the size of the ROM area located in the outer periphery of the barcode area is equal to the control data area 1720 + user data area 1730 in the optical disk with barcode 1700. On the other hand, in the optical disc 100 with a barcode, only the control data area 120 is present. When the barcode-added optical disc 100 and the barcode-added optical disc 1700 are each a DVD, as shown in FIGS. 1B and 17B, the barcode-added optical disc 1700 has a control data area 1720 + user data area 1730. The radial length of the control data area 120 is 0.5 mm in the optical disc 100 with a barcode, whereas the length in the radial direction is 34.5 mm.
[0051]
As shown in (1) above, when reading a signal from the control data area 120 of the optical disc 100 with barcode, the conventional optical disc apparatus once reads the signal from the control data region 1720 of the optical disc 1700 with barcode. After the optical head is moved to the user data area 130, it cannot be moved to the control data area 120 by one track jumping. Further, from the above (2), it can be seen that in the optical disc 100 with barcode, the length in the radial direction of the region where the light beam spot can move by performing one track jumping is extremely small.
[0052]
Thus, the access to the control data area in the barcode-added RAM cannot simply be applied to the control data area in the conventional barcode-added ROM. The present invention provides an optical disc apparatus suitable for access to a control data area in a bar code RAM. Although details will be described later, it should be noted that the present invention can also be applied to a barcoded ROM.
[0053]
(Embodiment 1)
FIG. 3 is a block diagram showing a configuration of an optical disc apparatus 300 that reads signals from the barcode-added optical disc 100 according to the present invention.
[0054]
The optical disc apparatus 300 reproduces necessary data recorded in the control data area 120 of the barcode-added optical disc 100 rotated by the disc motor 316 at the time of activation. Thereafter, the optical disc apparatus 300 records data in the user data area 130 or reproduces data recorded in the user data area 130.
[0055]
A light beam emitted from a light source 303 such as a laser is converged on the recording surface of the barcode-equipped disc 100 by a condenser lens 301, and a light beam spot is formed on the recording surface. The light reflected from the bar code disc 100 is received by the light receiving unit 304. The light receiving unit 304 generates a photocurrent according to the received light. This photocurrent is output as a signal of the portion where the light beam spot is formed on the optical disc 100 with barcode.
[0056]
The actuator 302 can drive the condenser lens 301 in a direction (focus direction) substantially perpendicular to the optical disc 100 with barcode and a radial direction (tracking direction) of the optical disc 100 with barcode.
[0057]
The condenser lens 301, the actuator 302, the light source 303, and the light receiving unit 304 are integrated as an optical head 315. The optical head 315 is mounted on the transfer unit 305, and by moving the transfer unit 305, the barcode-coated optical disc 100 can be moved in a substantially radial direction. In FIG. 3, the transfer unit 305 is shown in the shape of a table, but is not limited thereto. The transfer unit 305 can move on the base 307 to an arbitrary radial position of the barcode-equipped disc 100. A disk motor 316 and a stopper 306 are fixed to the base 307.
[0058]
The stopper 306 limits the moving range of the transfer unit 305 in the radial direction of the bar code disc 100 in order to prevent the transfer unit 305 from colliding with the disk motor 316. When the transfer unit 305 comes into contact with the stopper 306, the position of the light beam spot emitted from the optical head 315 is arranged so as to substantially coincide with the innermost circumference of the barcode area 110.
[0059]
The focus control, tracking control, and transfer control of the optical disc apparatus 300 will be further described.
[0060]
The control unit 320 controls the optical head 315. The control unit 320 includes a focus error signal generation unit 308, a tracking error signal generation unit 309, a microcomputer 310, a focus actuator drive circuit 311, a tracking actuator drive circuit 312, a transfer unit drive circuit 313, and a disk motor drive. Part 314.
[0061]
A signal output from the light receiving unit 304 is input to the preamplifier 317.
[0062]
Based on the output from the preamplifier 317, the focus error signal generation unit 308 generates a focus error signal. The microcomputer 310 commands the focus actuator drive circuit 311 based on the focus error signal. The focus actuator drive circuit 311 drives the actuator 302 based on a command from the microcomputer 310.
[0063]
Based on the output from the preamplifier 317, the tracking error signal generation unit 309 generates a tracking error signal (phase difference tracking error signal or push-pull tracking error signal). The microcomputer 310 commands the tracking actuator drive circuit 312 based on the tracking error signal. The tracking actuator drive circuit 312 drives the actuator 302 based on a command from the microcomputer 310.
[0064]
Based on the output from the preamplifier 317, the adder circuit 351 generates an RF signal. The adder circuit 351 outputs the RF signal to an automatic gain control circuit (hereinafter referred to as AGC (Automatic Gain Control)) 352. The AGC 352 adjusts the amplitude of the RF signal within a predetermined range, and outputs the adjusted RF signal to the barcode area determination unit 357.
[0065]
The barcode area determination unit 357 determines whether the RF signal input from the AGC 352 is a signal read from the barcode area 110 of the optical disk 100 with barcode.
In the present embodiment, the barcode area determination unit 357 functions as a control data area determination unit that determines whether the RF signal is a signal read from the control data area 120. The barcode area determination unit and the control data area determination unit are not limited to being provided integrally, and may be provided separately.
[0066]
The barcode area determination unit 357 outputs the determination result to the microcomputer 310. For example, when it is not desirable that the light beam spot on the barcode-coated optical disc 100 irradiated from the light source 303 is located in the barcode area 110, the barcode area determination unit determines that the light beam spot is located in the barcode area 110. If 357 determines, the barcode area determination unit 357 outputs the determination result to the microcomputer 310. Next, the microcomputer 310 controls the transfer unit driving circuit 313 so that the light beam spot moves to a region other than the bar coat region 110.
[0067]
The address detection circuit 360 detects the address where the light beam spot is located based on the output from the addition circuit 351.
[0068]
FIG. 4 is a block diagram illustrating configurations of the light receiving unit 304, the preamplifier 317, the focus error signal generation unit 308, the tracking error signal generation unit 309, and the addition circuit 351. The tracking error signal generation unit 309 includes a phase difference tracking error signal generation unit 309A and a push-pull tracking error signal generation unit 309B. The adder circuit 351 functions as an RF signal generation unit.
[0069]
As shown in FIG. 4, the light receiving unit 304 is divided into four areas A, B, C, and D. Each of the four areas generates a photocurrent according to the detected light amount. The light receiving unit 304 outputs the generated photocurrent to the I / V conversion units a, b, c, and d in the corresponding preamplifier 317. Here, areas A, B, C, and D of the light receiving unit 304 correspond to the I / V conversion units a, b, c, and d, respectively.
[0070]
Focus control will be described below. A focus error signal indicating an error in the vertical direction between the light beam spot irradiated from the light source 303 and collected by the condensing lens 301 and the optical disc 100 with barcode is output by the focus error signal generation unit 308 as an output signal of the preamplifier 317. Is generated based on A signal subjected to current-voltage conversion by the I / V conversion units a, b, c, and d in the preamplifier 317 is calculated by the focus error signal generation unit 308 to be output (a + d) − (b + c). Thus, the focus error signal is generated by the astigmatism method.
[0071]
The microcomputer 310 performs filter operations such as phase compensation and gain compensation on the focus error signal generated by the focus error signal generation unit 308. The microcomputer 310 outputs the result to the focus actuator drive circuit 311. Based on the drive signal generated by the focus actuator drive circuit 311, the actuator 302 drives the condenser lens 301 so that the light beam spot is in a predetermined convergence state with respect to the recording surface of the optical disc 100 with barcode. Focus control is realized with this.
[0072]
Next, tracking control will be described. An error in the radial direction with respect to the optical disc with barcode 100 between the light beam spot irradiated from the light source 303 and collected by the condenser lens 301 and the information track 210 on the optical disc with barcode 100 (see FIG. 2) is shown. The tracking error signal is generated by the tracking error signal generation unit 309 based on the output of the preamplifier 317. The error between the information track 210 formed on the recording surface of the optical disc 100 with barcode and the light beam spot output from the light source 303 is detected by the light receiving unit 304 that divides the light diffracted by the pits into four areas. It is represented by a signal indicating phase information of the detected diffracted light. The tracking error signal generation unit 309 compares the phase difference between the output (a + d) and the output (b + c), and generates a phase difference tracking error signal (Japanese Patent Laid-Open No. 62-165737).
[0073]
In particular, for the ROM area 140, the microcomputer 310 performs phase compensation, gain compensation, etc. on the phase difference tracking error signal and outputs the result to the tracking actuator drive circuit 312. The tracking actuator driving circuit 312 drives the actuator 302 so that the light beam spot correctly scans the information track 210 (see FIG. 2), thereby realizing tracking control.
[0074]
The phase difference tracking error signal is compensated for low frequency by the microcomputer 310 performing a filter operation. When the microcomputer 310 outputs the low-frequency signal to the transfer unit drive circuit 313, the transfer unit drive circuit 313 transfers the light beam passing through the center of the condenser lens 301 so as to pass through the center of the light receiving unit 304. The unit 305 is driven to realize transfer control.
[0075]
Based on the output from the preamplifier 317, the adder circuit 351 generates an RF signal that is an output (a + b + c + d) signal obtained by adding all the outputs of the I / V converters a, b, c, and d. The AGC 352 receives the RF signal, adjusts the amplitude of the RF signal to be within a predetermined range, and then outputs the RF signal to the barcode area determination unit 357.
[0076]
Hereinafter, a method for the optical head 315 to access the control data area 120 of the optical disk 100 with barcode according to the present invention will be described.
[0077]
FIG. 5 shows a flowchart 500 for the optical head 315 to access the control data area 120 of the optical disc 100 with barcode according to the present embodiment.
[0078]
First, the microcomputer 310 instructs the disk motor drive circuit 314 to rotate the disk 100 with the barcode, and the disk motor drive circuit 314 drives the disk motor 316 based on the command, and as a result, the disk The motor 316 rotates the optical disc 100 with bar code.
[0079]
In step 501, the microcomputer 310 outputs a pulse drive signal to the transfer unit drive circuit 313 with the tracking control being open. Based on this drive signal, the transfer unit drive circuit 313 moves the transfer unit 305 on which the optical head 315 is mounted in the inner circumferential direction along the radial direction with respect to the optical disc 100 with barcode.
[0080]
The stopper 306 is provided so that the light beam spot irradiated from the light source 303 does not move from the innermost circumference of the optical disc 100 with a barcode to the inside.
[0081]
The length of the drive signal output from the microcomputer 310 to the transfer unit drive circuit 313 is such that the optical head 315 can sufficiently return to the innermost circumference at any position in the radial direction of the optical disc 100 with a barcode. In order to limit the movement speed of the optical head 315 so that it does not become too fast, the drive signal is formed of a pulse train. Further, the speed of the transfer unit 305 that is moved by the drive signal is such a speed that the transfer unit 305 does not run backward to the outer periphery due to the reaction of the collision with the stopper 306. By such a drive signal, the optical head 315 moves to the innermost peripheral position of the optical disc 100 with barcode.
[0082]
After the transfer unit 305 has moved to the innermost circumference, the microcomputer 310 determines in step 502 that the light beam spot on the optical disc 100 with barcode formed by the optical head 315 mounted on the transfer unit 305 is the control data area. A drive signal is output to the transfer unit drive circuit 313 so as to move into the position 120. However, as described above, the control data area 120 is a very narrow area, and since it is necessary to consider a control error in the movement of the light beam spot, the transfer unit 305 is directly connected to the control data area 120. It is difficult to move. Therefore, according to the present invention, in consideration of variations in the movement accuracy of the transfer unit 305, the ROM area 140 of the barcode-equipped disk 100 shown in FIG. The transfer unit 305 is driven to move from R2 indicating the distance to a distance R4 indicating the radial length of the innermost circumference of the user data area 130 from the center of the optical disk.
[0083]
FIG. 6 is a waveform diagram of a transfer unit drive signal output from the microcomputer 310 to the transfer unit drive circuit 313 in steps 501 and 502. The horizontal axis of FIG. 6 indicates time, and the vertical axis indicates the voltage of the transfer unit drive signal. In step 501, the microcomputer 310 outputs a plurality of relatively short pulses to the transfer unit driving circuit 313. The plurality of relatively short pulses indicate an inner circumference movement command 610 for moving the transfer unit 305 to the innermost circumference. In step 502, the microcomputer 310 outputs one pulse having an arbitrary thickness to the transfer unit driving circuit 313. This pulse indicates an outer periphery movement command 620 for moving the transfer unit 305 from the innermost periphery to a desired position. In FIG. 6, an inner circumference movement command 610 is shown.
The sign of the voltage of the plurality of pulses is different from the sign of the pulse voltage indicating the outer periphery movement command 620. This is because the moving directions of the transfer unit 305 are different from each other.
[0084]
After the movement of the optical head 315, the microcomputer 310 performs focus control and tracking control in step 503 so that the light beam spot follows the information track.
[0085]
Next, in step 504, the barcode area determination unit 357 determines whether the light beam spot is located in the barcode area, that is, whether the signal output from the optical head 315 is a signal read from the barcode area 110. To do.
[0086]
When the barcode area determination unit 357 determines that the signal output from the optical head 315 is a signal read from the barcode area 110 (Yes in Step 504), in Step 505, the microcomputer 310 does not read the address. In addition, a command to move the transfer unit 305 to the outer peripheral side by a minute distance is output to the transfer unit driving circuit 313, and the optical head 315 is moved to the outer peripheral side (toward the control data area 120). In step 505, after moving the transfer unit 305 to the outer peripheral side, the optical head 315 mounted on the moved transfer unit 305 reads a signal from the optical disc 100 with a barcode. Thereafter, the process returns to step 504 again, and the optical head 315 mounted on the moved transfer unit 305 determines whether the signal read from the barcode-added optical disk 100 is a signal read from the barcode area 110 or not. The part 357 determines.
[0087]
Thus, as described above, the address indicating the position of the light beam spot in the barcode area 110 is used to determine whether the signal output from the optical head 315 is a signal read from the barcode area 110. This is because it is not guaranteed in terms of quality and reliability.
[0088]
When the barcode area determination unit 357 determines that the signal output from the optical head 315 is not a signal read from the barcode area 110 (No in Step 504), the signal output from the optical head 315 in Step 506 Is a signal read from the control data area 120 (that is, not a signal read from the barcode area 110). This is because in the optical disc 100 with barcode, the control data region 120 is provided adjacent to the barcode region 110 in the radial direction. Here, the same operation is performed even when the control data area determination unit determines that the signal output from the optical head 315 is a signal read from the control data area 120.
[0089]
Next, in step 507, the optical head 315 reads a signal from the control data area 120, and detects the address of the light beam spot on the optical disc 100 with barcode by the address detection circuit 360. From this address, the head position of the control data area 120 can be specified.
[0090]
Next, by controlling the optical head 315 so that one light beam spot jumps by one track, the optical head 315 is moved to the head position of the control data area 120 and necessary control data information is read out. In this specification, the control data information includes control data recorded in the control data area 120 and an address where the control data is recorded.
[0091]
In step 508, the optical head 315 reads the control data, and in step 509, reads the address where the read control data is recorded. In step 509, if the light beam spot is moved again to the barcode area 110 due to an external impact or the like before the optical head 315 reads the address, the optical head 315 cannot read the address (step 509). Yes), the light beam spot is moved from the barcode area 110 toward the control data area 120, and the steps after step 504 are repeated.
[0092]
The optical head 315 determines whether or not the reading of the control data information is completed in Step 510 after the reading of the control data in Step 508 and the reading of the address in Step 509 are completed. If the reading of the control data information has not been completed (No in Step 510), the process returns to Step 508, and the operation of reading the control data information from the control data area 120 is executed again. When the reading of the control data information has been completed (Yes in step 510), the operation of the flowchart 500 ends.
[0093]
Below, the specific structure of the barcode area | region determination part 357 is shown.
[0094]
FIG. 7A shows details of barcode area determination unit 357A in the present embodiment. The barcode area determination unit 357A includes a binarization circuit 710, a maximum cycle detection unit 720, and a cycle comparison unit 730.
[0095]
In the present embodiment, the barcode area determination unit 357A determines whether the signal output from the optical head 315 is a signal read from the barcode area 110, out of the period of the signal read from the control data area 120. It is determined based on whether it is longer than the set cycle which is the maximum cycle.
[0096]
When the barcode-added optical disc 100 is an 8-16 modulation DVD, the maximum period of the signal read from the control data area 120 is 18T, and the longest mark length (the maximum pit length of the pits 220 ( Hereinafter, the maximum pit length)) is 14T. Here, T represents a read clock cycle.
[0097]
In general, the period of the signal read from the barcode area 110 is longer than the maximum period 18T of the signal read from the control data area 120. This is to divide the frequency band of the 8-16 modulated signal read from the control data area 120 and the signal read from the barcode 150 in the barcode area 110, and is defined by the standard.
[0098]
Here, FIG. 3 will be referred to again. The adder circuit 351 receives a signal output from the optical head 315 via the preamplifier 317 and generates an RF signal. The RF signal is input to the barcode area determination unit 357 via the AGC 352.
[0099]
As shown in FIG. 7A, the RF signal is input to the binarization circuit 710. The binarization circuit 710 binarizes the RF signal at a predetermined slice level.
[0100]
FIG. 8 shows an example of a binarized RF signal waveform when the RF signal is a random signal. When the optical disc with barcode 100 is an 8-16 modulation DVD, the maximum period of the signal read from the control data area 120 is 18T, and the longest mark length in that case is 14T. The shortest mark length of the signal read from the control data area 120 is 3T.
[0101]
Referring to FIG. 7A again, the maximum period detector 720 receives the binarized RF signal. The maximum cycle detection unit 720 detects the maximum cycle of the received RF signal at the H level / L level (rising from rising or falling from falling) within a predetermined time.
[0102]
Here, as the predetermined time for the maximum period detection unit 720 to detect the maximum period, it is necessary to set a time for detecting a signal by at least one barcode 150 (see FIG. 1). For example, when the optical disc 100 with barcode is a DVD, it is necessary to detect the maximum period detection unit 720 for a time longer than the time corresponding to the DVD rotating 11/12 rounds.
[0103]
The range in which the barcode 150 is recorded on the DVD is defined as a disc rotational speed of 1440 rpm, a read clock cycle of 8.89 μsec, and barcode data 2601 to 73441 bytes. This is because one barcode 150 exists within an angle corresponding to 2.2 rotations.
[0104]
The period comparison unit 730 compares the maximum period detected by the maximum period detection unit 720 with the set period, and determines whether or not the RF signal is a signal read from the control data area 120. As described above, when the optical disc 100 with barcode is an 8-16 modulation DVD, the maximum period of the signal read from the control data area 120 is determined to be 18T. The maximum period of the signal read from the barcode area 110 is greater than 18T.
[0105]
Here, for example, the period 18T is set as the set period in the period comparison unit 730, and the period comparison unit 730 compares the maximum period detected by the maximum period detection unit 720 with the set period, and the maximum period is greater than the set period. Is larger, the period comparison unit 730 determines that the RF signal is a signal read from the barcode area 110. When the maximum period is equal to or less than the set period, the period comparison unit 730 determines that the RF signal is not a signal read from the barcode area 110 but a signal read from the control data area 120. Thus, the barcode area determination unit 357A can determine whether the RF signal (that is, the signal read by the optical head 315) is a signal read from the barcode area 110.
[0106]
The maximum period detected by the maximum period detection unit 720 may be compared with a value (for example, 20 T or more) larger than the set period in consideration of the detection error instead of the set period 18T described above. In this specification, when the optical disc 100 with a barcode is an 8-16 modulation DVD, the maximum period is compared with a value of 20T or more in consideration of a detection error, and the maximum period is determined to be 20T or more. Suppose that the maximum period is sufficiently larger than the set period.
[0107]
FIG. 7B shows details of the barcode area determination unit 357B in a modification of the present embodiment. The barcode area determination unit 357B includes a binarization circuit 710, a maximum cycle detection unit 720, a cycle comparison unit 730, and a read clock cycle detection unit 740. The barcode area determination unit 357B is the same as the barcode area determination unit 357A except that the barcode area determination unit 357B further includes a read clock cycle detection unit 740.
[0108]
The read clock cycle detection unit 740 receives the RF signal binarized by the binarization circuit 710 and generates a read (READ) clock cycle. The read clock cycle detection unit 740 generates a read clock cycle by, for example, a phase lock loop (hereinafter, PLL).
[0109]
Based on the maximum cycle detected by the maximum cycle detection unit 720 and the read clock cycle generated by the read clock cycle detection unit 740, the cycle comparison unit 730 is the number of clocks of the read clock cycle. (Hereinafter referred to as the maximum number of clocks).
[0110]
Therefore, when the optical disc 100 with barcode is an 8-16 modulation DVD, for example, the coefficient 18 is set in advance in the period comparison unit 730 as the set clock coefficient, and the period comparison unit 730 compares the maximum number of clocks with the set clock coefficient. To do. When the maximum number of clocks is larger than the set clock coefficient, the period comparison unit 730 determines that the RF signal is a signal read from the barcode area 110. When the maximum number of clocks is equal to or less than the set clock coefficient, the period comparison unit 730 determines that the RF signal is not a signal read from the barcode area 110 but a signal read from the control data area 120.
[0111]
As described above, the barcode area determination unit 357B can also determine whether the RF signal (that is, the signal read by the optical head 315) is the signal read from the barcode area 110.
[0112]
Thus, according to the first embodiment, the light beam spot is in the barcode area 110 until the optical head 315 accesses the control data area 120 and the reading of the control data information from the control data area 120 is completed. By continuing the determination of whether or not the optical head is located, the light beam spot formed from the optical head 315 can be stably positioned in the control data area 120, and the start-up stability of the optical disc apparatus 300 is greatly increased. Can be improved.
[0113]
(Embodiment 2)
The optical disc apparatus in the present embodiment is the same as the optical disc apparatus 300 shown in FIG. 3 except for the barcode area determination unit. Therefore, redundant description is omitted for the purpose of simplifying the description.
[0114]
FIG. 9A shows a barcode area determination unit 357C in the present embodiment. The barcode area determination unit 357C is the barcode area determination unit 357B described with reference to FIG. 7B except that the read clock period detection unit 740 includes a shortest mark length detection unit 910 and a read clock period derivation unit 920. It is the same.
[0115]
The shortest mark length detection unit 910 receives the RF signal binarized by the binarization circuit 710, and within a predetermined time, the shortest mark time (only the H level or L level of the binarized RF signal) The shortest mark length) is detected. Here, the predetermined time is a time during which the barcode area determination unit 357C detects a signal from at least one barcode 150 (see FIG. 1).
[0116]
The read clock cycle deriving unit 920 derives the read clock cycle T based on the shortest mark length detected by the shortest mark length detection unit 910.
[0117]
For example, when the optical disc with barcode 100 is an 8-16 modulation DVD, the shortest mark length of a signal read from the control data area 120 is 3T (T is a read clock cycle). The read clock cycle deriving unit 920 derives the read clock cycle T by calculating the shortest mark length ÷ 3 = T. Thus, in this embodiment, the read clock cycle is derived based on the shortest mark length of the RF signal.
[0118]
The derived read clock cycle is handled in the same manner as described in the barcode area determination unit 357B. Specifically, the cycle comparison unit 730 obtains the maximum number of clocks based on the maximum cycle of the RF signal detected by the maximum cycle detection unit 720 and the derived read clock cycle. The period comparison unit 730 compares the maximum number of clocks with the set clock coefficient. When the maximum clock number is larger than the set clock coefficient, the period comparison unit 730 determines that the RF signal is a signal read from the barcode area 110 and outputs the determination result to the microprocessor 310. When the maximum number of clocks is less than or equal to the set clock coefficient, the period comparison unit 730 informs the microprocessor 310 that the RF signal is a signal read from the control data area 120 (a signal read from other than the barcode area 110). Output. As described above, when the optical disc 100 with barcode is an 8-16 modulation DVD, the set clock coefficient is 18, but the maximum number of clocks is set to 20 or more larger than the set clock coefficient in consideration of the detection error. It is preferable to compare with the value.
[0119]
As described above, in this embodiment, even when the PLL is unstable and cannot be stably detected with the read clock cycle T, the read clock cycle can be derived from the actually detected RF signal. Thereby, it can be determined whether or not the light beam spot formed from the optical head 315 is located in the barcode area 110.
[0120]
(Embodiment 3)
The optical disc apparatus in the present embodiment is the same as the optical disc apparatus 300 shown in FIG. 3 except for the barcode area determination unit. Therefore, redundant description is omitted for the purpose of simplifying the description.
[0121]
FIG. 9B shows a barcode area determination unit 357D in the present embodiment. The barcode area determination unit 357D is the same as the barcode area determination unit 357A described with reference to FIG. 7A, except that the rotation period measurement unit 930 is provided.
[0122]
The rotation period measuring unit 930 is connected to the disk motor 316 (see FIG. 3), and measures the rotation period of the optical disc 100 with a barcode by the disk motor 316.
[0123]
The period comparison unit 730 compares the maximum period of the RF signal detected by the maximum period detection unit 720 with the rotation period measured by the rotation period measurement unit 930, so that the light beam spot is in the barcode region 110. Whether it is located can be determined.
[0124]
The relationship between the maximum period of the RF signal based on the signal read from the control data area 120 by the optical head 315 and the rotation period of the optical disk 100 with barcode is determined in advance, and the maximum of the RF signal based on the signal read from the barcode area 110 is determined. The relationship between the period and the rotation period of the optical disc 100 with barcode is different. Therefore, also in the present embodiment, the barcode area determination unit 357D can determine whether or not the RF signal is a signal read from the barcode area 110 from the relationship between the maximum period and the rotation period. it can.
[0125]
(Embodiment 4)
The optical disc apparatus in the present embodiment is the same as the optical disc apparatus 300 shown in FIG. 3 except for the barcode area determination unit. Therefore, redundant description is omitted for the purpose of simplifying the description.
[0126]
In this embodiment, a smoothed signal obtained by smoothing the RF signal is generated, a time during which the smooth signal changes by a predetermined amount or more is compared with a preset set time, and the RF signal is converted into a bar based on the comparison result. It is determined whether the signal is read from the code area 110.
[0127]
FIG. 10 shows a barcode area determination unit 357E in the present embodiment. The barcode area determination unit 357E includes a low-pass filter 1010, a binarization circuit 1020, and a comparison unit 1030.
[0128]
11 inputs an RF signal as shown in FIG. 11A, which is a waveform diagram showing changes in the signal in the barcode area determination unit 357E, to the low-pass filter 1010. The low pass filter 1010 generates an AS signal obtained by smoothing the RF signal, as shown in FIG. The low-pass filter 1010 functions as a smoothing unit, and the AS signal functions as a smoothing signal. The AS signal is a signal that has been smoothed by removing a frequency equal to or higher than a set period (for example, 18T).
[0129]
The binarization circuit 1020 receives the AS signal, slices the AS signal at a predetermined level, rounds it to the H level and L level according to the magnitude of the signal, and binarizes as shown in FIG. The AS signal thus output is output to the comparison unit 1030.
[0130]
The comparison unit 1030 measures the L level period of the binarized AS signal. When the L level period of the binarized AS signal is longer than a predetermined time, the comparison unit 1030 determines that the RF signal input to the barcode area determination unit 357E is a signal read from the barcode area 110. .
[0131]
Usually, the period in which the smoothed signal obtained by smoothing the RF signal changes by a predetermined amount or more exists only in the case of the smoothed signal generated from the signal read from the barcode area 110 and read from the control data area 120. The smoothed signal generated from the signal does not change. Therefore, in the present embodiment, the barcode area determination unit 357E determines whether or not the RF signal is a signal read from the barcode area 110 from a period in which the smoothed signal obtained by smoothing the RF signal changes by a predetermined amount or more. Can be determined.
[0132]
According to the present embodiment, since it is not necessary to detect the read clock cycle by the PLL, even when the read clock cycle T cannot be stably generated, the signal output from the optical head 315 is output from the barcode area 110. It is possible to accurately determine whether the signal is a read signal.
[0133]
(Embodiment 5)
The optical disc apparatus in the present embodiment is the same as the optical disc apparatus 300 shown in FIG. 3 except for the barcode area determination unit. Therefore, redundant description is omitted for the purpose of simplifying the description.
[0134]
FIG. 12 shows a barcode area determination unit 357F according to the present embodiment. The barcode area determination unit 357F is the same as the barcode area determination unit 357E illustrated in FIG. 10 except that an amplitude signal generation unit 1210 is provided instead of the low-pass filter 1010. The amplitude signal generation unit 1210 includes an upper envelope detection unit 1220, a lower envelope detection unit 1230, and an RF amplitude detection unit 1240.
[0135]
FIG. 13 is a waveform diagram showing changes in the signal in the barcode area determination unit 357F.
[0136]
The upper envelope detector 1220 and the lower envelope detector 1230 receive the RF signal as shown in FIG. The upper envelope detection unit 1220 generates an RF upper envelope signal indicating the upper limit of the RF signal after the AGC 352 as shown in FIG. As shown in FIG. 13C, the lower envelope detection unit 1230 generates an RF lower envelope signal indicating the lower limit of the RF signal. The RF amplitude detector 1240 generates an amplitude signal as shown in FIG. 13D from the difference between the upper envelope signal and the lower envelope signal.
[0137]
The binarization circuit 1020 slices the amplitude signal at a predetermined level, and rounds the amplitude signal into an H level and an L level as shown in FIG. The comparison unit 1030 measures the H level period of the binarized amplitude signal. When the H level period of the binarized amplitude signal is longer than a predetermined time, the comparison unit 1030 determines that the RF signal input to the barcode area determination unit 357F is a signal read from the barcode area 110. .
[0138]
Usually, the period in which the amplitude signal of the RF signal changes by a predetermined amount or more exists only in the case of the amplitude signal generated from the signal read from the barcode area 110, and is generated from the signal read from the control data area 120. The amplitude signal does not change. Therefore, in the present embodiment, the barcode area determination unit 357F determines whether or not the RF signal is a signal read from the barcode area 110 from a period in which the amplitude signal of the RF signal changes by a predetermined amount or more. can do.
[0139]
Also in this embodiment, even when the read clock cycle T is not generated due to the PLL being unstable, the read clock cycle by the PLL is not used, so that the signal output from the optical head 315 is read from the barcode area 110. It is possible to accurately determine whether or not the signal is a signal.
[0140]
(Embodiment 6)
FIG. 14 shows an optical disc apparatus 1400 according to the present embodiment. The optical disc apparatus 1400 in the present embodiment is the same as the optical disc apparatus 300 shown in FIG. 3 except that it includes a barcode data reproducing unit 1410 and a RAM register 1450 provided in the microcomputer 310. Therefore, redundant description is omitted for the purpose of simplifying the description. The barcode data reproduction unit 1410 includes a band pass filter 1420, a binarization circuit 1430, and a barcode decoding unit 1440. The RAM register 1450 functions as a barcode data storage unit.
[0141]
In this embodiment, when the barcode area determination unit 357 determines that the signal output from the optical head 315 is a signal read from the barcode area 110, the barcode data is reproduced by the barcode data reproduction unit 1410. Stored in the RAM register 1450.
[0142]
In the optical disc apparatus 1400, by adding the output signals of the preamplifier 317, the addition circuit 351 generates an RF signal from the signal recorded on the information track on the optical disc 100 with barcode.
[0143]
The RF signal that is the output of the addition circuit 351 is input to the barcode area determination unit 357. The barcode area determination unit 357 determines whether or not the light beam spot is located in the barcode area 110 based on the input RF signal.
[0144]
FIG. 15 shows the signal output of each part for explaining the waveform shaping process in which the barcode data reproduction unit 1410 reproduces the signal output from the optical head 315 when the light beam spot is located in the barcode region 110. It is a waveform diagram.
[0145]
The barcode data reproduction unit 1410 receives the RF signal from the addition circuit 351. When the light beam spot is located in the barcode area 110, the RF signal shown in FIG. 15A passes through the bandpass filter 1420, and as shown in FIG. The component outside the signal band is removed, and the signal by the bar code 150 appears more clearly.
[0146]
The binarization circuit 1430 binarizes the barcode data that is the filtered analog signal at a predetermined level, and outputs a signal as shown in FIG. 15C to the barcode decoding unit 1440. The barcode data reproduced by the barcode decoding unit 1440 is input to the microcomputer 310 and stored in the RAM register 1450 built in the microcomputer 310. The method of moving the light beam spot to the control data area 120 is realized by the same method as described above.
[0147]
In the present embodiment, when the light beam spot moves into the barcode area 110, the barcode data is reproduced and the reproduced barcode data is stored. As described above, since the address indicating the position of the light beam spot in the barcode area 110 is not guaranteed from the viewpoint of quality and reliability, the microcomputer 310 does not read the address, and the light beam spot is transferred to the control data area 120. A command for moving only a small amount toward is output to the transfer unit drive circuit 313. After the light beam spot moves toward the outer peripheral side, the barcode area determination unit 357 determines again whether or not the light beam spot has moved to the control data area 120.
[0148]
When the above operation is repeated and the maximum period of the RF signal is in the vicinity of the set period, for example, when the optical bar code-added optical disc 100 is an 8-16 modulation DVD, the maximum period is in the vicinity of 18T which is the set period. The barcode area determination unit 357 determines that the light beam spot has moved from the barcode area 110 to the control data area 120. Then, the address detection circuit 360 detects the address of the moved light beam spot, and specifies the head address of the control data area 120 from the detected address. Thereafter, the light beam spot is moved by repeating one-track jumping at the head address, and necessary control data is read out. If the light beam spot is moved again to the barcode area 110 due to an external impact or the like while the control data is being read from the control data area 120, the barcode area determination unit 357 determines that the light beam spot is a barcode. Since it is determined to be located within the area 110, the operation of moving the light beam spot from the barcode area 110 toward the control data area 120 is repeated as described above.
[0149]
As described above, according to the sixth embodiment of the present invention, when the light beam spot is located in the barcode area 110 while accessing the control data area 120, the barcode data is required later. For this purpose, the barcode data is reproduced in advance and the reproduced barcode data is stored. Therefore, when the barcode data is needed later, it is not necessary to search for the barcode data, and the time for reading the barcode data can be omitted.
[0150]
(Embodiment 7)
FIG. 16 shows an optical disc apparatus 1600 according to this embodiment. The optical disc apparatus 1600 in the present embodiment is the same as the optical disc apparatus 300 shown in FIG. 3 except that it includes a position sensor 1610 and a RAM register 1450 provided in the microcomputer 310. Therefore, redundant description is omitted for the purpose of simplifying the description.
[0151]
In the optical disc apparatus 1600, the adder circuit 351 adds the signals read from the information tracks of the optical disc 100 with a bar code based on the output from the preamplifier 317, similarly to the optical disc apparatus 300, and generates an RF signal.
[0152]
The RF signal that is the output of the addition circuit 351 is input to the barcode area determination unit 357, and it is determined whether or not the light beam spot is located in the barcode area 110 based on the input RF signal. The method of moving the light beam spot toward the control data area 120 is realized by the above-described operation.
[0153]
When a light beam spot is present in the barcode area 110, the address indicated by the signal output from the optical head 315 is not guaranteed from the viewpoint of quality and reliability. In this case, the microcomputer 310 outputs a command to move the light beam spot to the outer peripheral side by a small amount without reading the address, to the transfer unit driving circuit 313. After the light beam spot moves toward the outer control data area 120, the barcode area determination unit 357 determines again whether or not the light beam spot is located in the control data area 120.
[0154]
When the above operation is repeated and the maximum period of the RF signal is near the set period, for example, when the optical bar code-added optical disc 100 is an 8-16 modulation DVD, the maximum period of the RF signal is changed from 20T to around the set period of 18T. In this case, the barcode area determination unit 357 determines that the light beam spot is not located in the barcode area 110 and the movement into the control data area 120 is completed. During this time, address reading is not performed.
[0155]
By this processing, when the light beam spot completely moves from the barcode area 110 into the control data area 120, the RAM register 1450 stores the boundary position between the barcode area 110 and the control data area 120. The boundary position is a position where the barcode area determination unit 357 determines that the light beam spot has moved from the barcode area 110 to the control data area 120. The position is detected by detecting the address of the track of the optical disc 100 with barcode or the number of feed pulses from the stopper 306 or the position of the optical head 315 when the feed motor for moving the transfer unit 305 is a stepping motor. A position sensor 1610 is attached to a predetermined position of the optical head 315, and the boundary position is detected as a value that can be recognized by the microcomputer 310 by using position information in the position sensor 1610 or the like.
[0156]
The obtained boundary position information is input to the microcomputer 310 through an AD converter (not shown) or the like, and the boundary position information is stored in a RAM register 1450 built in the microcomputer 310. In this embodiment, the RAM register 1450 functions as a position storage unit.
[0157]
For example, when the feed motor for moving the transfer unit 305 is a stepping motor, the value of the position sensor 1610 is cleared after step 501 based on the flowchart 500 shown in FIG. 5 described above. Thereafter, the processing is performed in the order of Steps 502 to 506, and the value of the position sensor 1610 at the time when Step 507 is completed, for example, the number of pulses from the stopper 306 in the outer circumferential direction is 10 pulses, and the movement to the control data area 120 is completed In this case, a value of 10 is stored in the RAM register 1450.
[0158]
As described above, when the seventh embodiment is used, when it is necessary to read the barcode data recorded in the barcode area 110 in the subsequent operation, the microcomputer 310 stores the barcode stored in the built-in RAM register 1450. With reference to the boundary position information between the code area 110 and the control data area 120, the light beam spot can be moved, and the barcode data can be read at high speed.
[0159]
In addition, when the light beam spot moves from the user data area 130 to the control data area 120, the bar code area 110 and the control data area 120 stored in the RAM register 1450 are stored in the user data area 130 even if it is sent back. By performing the movement with reference to the boundary position information, the access reliability of the control data area 120 can be further improved.
[0160]
In the first to seventh embodiments, the case where the barcode-added optical disc 100 is a barcode-added RAM has been described. However, the present invention can be applied to an optical disc including a barcode area, and can also be applied to a barcode-added ROM. When the present invention is applied to a barcode-added ROM, the light beam spot is temporarily moved to the user data area through the control data area, and then the light beam spot is positioned in the control data area. Thus, the control data area can be accessed from the barcode area side.
[0161]
【The invention's effect】
As described above, according to the present invention, a method for accessing a control data area suitable for a bar code RAM is provided.
[0162]
Further, according to the present invention, it is possible to stably access the control data area in a barcode-added optical disk including a barcode area regardless of RAM or ROM, and provide a highly reliable optical disk apparatus. It becomes possible.
[Brief description of the drawings]
FIG. 1 is a schematic diagram of a RAM with a barcode according to the present invention.
FIG. 2 is a schematic diagram of information tracks and pits in a ROM area of a barcode-added ROM and a ROM area of a barcode-attached RAM according to the present invention.
FIG. 3 is a block diagram showing a configuration of an optical disc apparatus according to the present invention.
FIG. 4 is a block diagram showing configurations of a light receiving unit, a preamplifier, a focus error signal generation unit, a tracking error signal generation unit, and an addition circuit according to the present invention.
FIG. 5 is a flowchart for accessing a control data area according to the present invention;
FIG. 6 is a waveform diagram of a transfer unit driving signal according to the present invention.
FIG. 7A is a block diagram showing in detail the configuration of a barcode area determination unit according to Embodiment 1;
7B is a block diagram showing in detail a configuration of a barcode area determination unit according to a modification of the first embodiment. FIG.
FIG. 8 is a waveform diagram for explaining a signal detected by a maximum period detector according to the present invention.
FIG. 9A is a block diagram showing in detail the configuration of a barcode area determination unit according to Embodiment 2;
FIG. 9B is a block diagram showing in detail the configuration of the barcode area determination unit according to the third embodiment.
FIG. 10 is a block diagram showing in detail the configuration of a barcode area determination unit according to the fourth embodiment.
FIG. 11 is a waveform diagram for explaining a waveform shaping process until a barcode area is determined by a barcode area determination unit according to the fourth embodiment;
FIG. 12 is a block diagram showing in detail a configuration of a barcode area determination unit according to the fifth embodiment.
FIG. 13 is a waveform diagram for explaining waveform shaping processing until a barcode area is determined in the barcode area determination unit according to the fifth embodiment;
FIG. 14 is a block diagram showing a configuration of an optical disc device according to a sixth embodiment.
FIG. 15 is a waveform diagram for explaining waveform shaping processing until the barcode signal is decoded in the optical disc apparatus according to the sixth embodiment;
FIG. 16 is a block diagram showing a configuration of an optical disc device according to a seventh embodiment.
FIG. 17 is a schematic diagram of a ROM with a barcode.
[Explanation of symbols]
100 Barcode RAM
110 Barcode area
120 Control data area
130 User data area
140 ROM area
145 RAM area
150 barcode
210 Information Track
220 pits
300, 1400, 1600 optical disc apparatus
301 condenser lens
302 Actuator
303 Light source
304 light receiving unit
305 Transfer section
306 Stopper
307 base
308 Focus error signal generator
309 Tracking error signal generator
310 Microcomputer
311 Focus actuator drive circuit
312 Tracking actuator drive circuit
313 Transfer unit drive circuit
314 Disc motor drive circuit
315 Optical head
316 disk motor
317 preamplifier
351 Adder circuit
352 AGC
357, 357A, 357B, 357C, 357D, 357F, 357E Barcode area determination unit
360 Address detection circuit
710 Binary circuit
720 Maximum period detector
730 Period comparison unit
740 Read clock cycle detector
910 Minimum mark length detector
920 Read clock cycle deriving unit
930 Rotation period measurement unit
1010 Low pass filter
1020 Binary circuit
1030 comparator
1210 Amplitude signal generator
1220 Upper envelope detector
1230 Lower envelope detector
1240 RF amplitude detector
1410 Barcode data playback unit
1420 Bandpass filter
1430 Binary circuit
1440 Barcode decoding unit
1450 RAM registers
1610 Position sensor

Claims (12)

A user data area in which user data is recorded, a control data area that is provided adjacent to the user data area in the radial direction and includes at least physical data relating to the type and format of the optical disc, and the control data area An optical disc apparatus that performs recording or reproduction of information on an optical disc provided with a bar code region in which information unique to the optical disc is formed, and is provided in an area adjacent to each other in the radial direction,
An optical head that irradiates the optical disc with a light beam to form a light beam spot on the optical disc and outputs a signal corresponding to the light beam reflected by the optical disc;
A barcode area determination unit that determines whether or not the light beam spot is located in the barcode area in accordance with a signal output from the optical head;
Tracking control is performed using the push-pull method in the user data area and the phase difference method in the control area, and information on a predetermined address of the optical disk is moved by moving the light beam spot of the optical head. And a control unit for accessing
When the control unit performs control to access the light beam spot of the optical head to a predetermined address position of the control data region, the light beam spot is positioned in the barcode region by the barcode region determination unit. If it is determined, the optical head is controlled so that the light beam spot moves toward the control data area, and the light beam spot is positioned in the barcode area by the barcode area determination unit. An optical disc apparatus that detects an address when it is determined not to do so. A control data area determination unit for determining whether or not the light beam spot is located in the control data area;
An address for detecting an address indicating the position of the light beam spot in the control data area based on a signal output from the optical head when it is determined that the light beam spot is located in the control data area A detection unit;
The optical disk apparatus according to claim 1, wherein the control unit controls movement of the optical head based on an address detected by the address detection unit. A control data area determination unit for determining whether the light beam spot is located in the control data area;
The control unit, until the light beam spot is determined to be located in the control data area, the light beam spot repeatedly controlling said optical head to move toward the control data area, according to claim 2 An optical disk device according to the above. The maximum period of the period of the signal output from the optical head according to the light beam reflected by the control data area is set as a set period,
The period of a signal output from the optical head in response to the light beam reflected by the barcode area has a period longer than the set period.
The barcode area determination unit
A maximum period detector for detecting the maximum period of the signal output from the optical head;
A period comparison unit that compares the maximum period detected by the maximum period detection unit with the set period to determine whether the light beam spot is located in the barcode area. 1. An optical disc device according to 1. If the maximum cycle detected by the maximum cycle detection section is sufficiently large compared to the set cycle, the cycle comparing section determines that the light beam spot is positioned at the barcode region, in claim 4 The optical disk device described. The barcode area determination unit
A maximum period detector for detecting a maximum period of a signal output from the optical head;
A read clock cycle detection unit for detecting a read clock cycle of a signal output from the optical head;
The signal is set according to the ratio of the maximum cycle detected by the maximum cycle detector and the read clock cycle detected by the read clock cycle detector and the light beam reflected by the barcode area. The optical disk apparatus according to claim 1, further comprising: a period comparison unit that compares the set clock coefficient with each other to determine whether or not the light beam spot is located in the barcode area. The read clock cycle detection unit
A shortest mark length detection unit for detecting a shortest mark length of a signal read from the optical disc;
The optical disk apparatus according to claim 6 , further comprising: a read clock cycle deriving unit that derives a read clock cycle based on a shortest mark length detected by the shortest mark length detection unit and a coefficient of a predetermined shortest mark length. . The barcode area determination unit
A maximum period detector for detecting a maximum period of a signal read from the optical disc;
A rotation period measuring unit for measuring the rotation period of the optical disc;
A cycle for determining whether or not the light beam spot is located in the barcode region based on the maximum cycle detected by the maximum cycle detector and the rotation cycle measured by the rotation cycle measurement unit. The optical disk device according to claim 1, further comprising: a comparison unit.   The bar code area determination unit determines whether or not the light beam spot is located in the bar code area for a predetermined period equal to or more than a time corresponding to 11/12 rotation of the optical disc. The optical disk device described. The barcode area determination unit
A smoothing unit that outputs a smoothed signal obtained by smoothing a signal output from the optical head;
The comparison part which compares the time when the said smooth signal changes more than predetermined amount, and predetermined time, and determines whether the said light beam spot is located in the said barcode area | region is provided. Optical disk device. The barcode area determination unit
An amplitude signal generating unit that generates an amplitude signal from a signal output from the optical head;
A comparison unit that compares a predetermined time with a time when the amplitude signal generated by the amplitude signal generation unit changes by a predetermined amount or more, and determines whether or not the light beam spot is located in the barcode region; The optical disc apparatus according to claim 1, comprising: In the barcode area, barcode data is recorded,
When it is determined that the light beam spot is located in the barcode area, a barcode data reproducing unit that reproduces the barcode data in accordance with a signal output from the optical head, and the reproduced barcode data The optical disc apparatus according to claim 1, further comprising a bar code data storage unit for storing.

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