JP4955592B2 - Drawing apparatus and drive signal generation apparatus - Google Patents

Description

  The present invention relates to a drawing apparatus and a drive signal generation apparatus.

  In recent years, with the spread of information recording media such as optical discs, drawing devices that draw on the label surface of optical discs have also become widespread.

  There are various specific methods for drawing on an optical disk. For example, there is a method of drawing by spraying ink on the label surface of the optical disk. There is also a method of drawing by irradiating a laser beam on the label surface of the optical disk. In the latter case, the heat-sensitive layer formed on the label surface of the optical disk is altered with the irradiation of the laser beam, so that a desired image is drawn on the label surface of the optical disk.

Patent Documents 1 and 2 disclose a technique in which an optical pickup unit is used to irradiate a heat-sensitive surface of an optical disc with laser light and form an image there. Patent Document 3 discloses a technique for correcting a drive waveform input to a stepping motor in order to realize highly accurate traverse feed.
JP 2003-203348 A JP-T-2006-512718 JP 2003-187471 A

  By the way, when drawing a desired image (image, character, etc.) on the drawing surface of the optical disc, it is strongly required to suppress deterioration in image quality such as display unevenness and image distortion in the finally drawn image.

  For example, when a desired image is drawn on the drawing surface of an optical disk based on irradiation with laser light, it is required to move the optical pickup unit stepwise with high accuracy. However, no index indicating the position in the drawing surface of the optical disc is set, and servo control cannot be performed. Therefore, in order to suppress degradation of the image quality of the finally drawn image, it is necessary to increase the feeding accuracy of the feeding mechanism of the optical pickup unit. However, in reality, it is difficult to increase the feeding accuracy of the feeding mechanism itself of the optical pickup unit due to various factors (for example, machining accuracy of the mechanical transmission mechanism, variation in characteristics of the driving source, etc.).

  As described above, it is strongly desired to suppress the deterioration of the image quality of the drawn image that is finally drawn in accordance with the displacement of the optical pickup unit (light irradiation unit) with respect to the target position.

  A drawing apparatus according to the present invention includes a light irradiation unit that irradiates light on a drawing surface of a drawing object via an optical component, and the light irradiation unit at each of a plurality of target positions set in advance on the drawing surface. A first driving unit for step-moving the light irradiation unit to sequentially arrange the positions, and a target position and a position between the arrangement positions of the light irradiation unit actually moved by the first driving unit toward the target position An error calculating unit that calculates an error value corresponding to a deviation amount corresponding to each of the plurality of target positions, and the first driving unit that arranges the light irradiation unit at each of the plurality of target positions. A second drive unit that displaces the optical component in accordance with the error value associated with the current target position of the light irradiation unit in synchronization with the step movement of the light irradiation unit.

  The second driving unit is synchronized with the step movement of the light irradiating unit by the first driving unit for arranging the light irradiating unit at each of the plurality of target positions, and an error associated with the current target position of the light irradiating unit. The optical component is displaced according to the value. Thus, by displacing the optical component by the second drive unit, it is possible to effectively suppress the influence of the displacement of the light irradiation unit by the first drive unit.

  The drive signal generation device according to the present invention includes a first drive for sequentially moving the optical pickup unit in order to sequentially arrange the optical pickup unit at each of a plurality of preset target positions on the drawing surface of the drawing object. A drive signal generating device for generating a signal and a second drive signal for moving an optical component in the optical pickup unit, the first drive signal generating unit for generating the first drive signal, and in the optical pickup unit Based on the output of the light receiving unit, an error value corresponding to a positional deviation amount between the target position and the position of the optical pickup unit actually moved toward the target position is associated with each of the plurality of target positions. In synchronization with the generation of the first drive signal for placing the optical pickup unit at each of a plurality of target positions. Comprising a second drive signal generator for generating a second drive signal of a signal value corresponding to the error value associated with a target position of the times, the.

  The second drive signal generation unit responds to an error value associated with the current target position of the optical pickup unit in synchronization with the generation of the first drive signal for arranging the optical pickup unit at each of the plurality of target positions. The second drive signal having the signal value is generated. By displacing the optical component with the second drive signal, it is possible to effectively suppress the influence of the displacement of the optical pickup unit based on the first drive signal.

  ADVANTAGE OF THE INVENTION According to this invention, the image quality fall of the drawing image finally drawn with the position shift of the optical pick-up part (light irradiation part) with respect to a target position can be suppressed.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Each embodiment is simplified for convenience of explanation. Since the drawings are simple, the technical scope of the present invention should not be interpreted narrowly based on the drawings. The drawings are only for explaining the technical matters, and do not reflect the exact sizes or the like of the elements shown in the drawings. The same elements are denoted by the same reference numerals, and redundant description is omitted. Words indicating directions such as up, down, left and right are used on the assumption that the drawing is viewed from the front.

[First Embodiment]
A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a block diagram illustrating a configuration of a drawing apparatus. FIG. 2 is an explanatory diagram showing a configuration of the optical pickup unit. FIG. 3 is an explanatory diagram showing the structure of the error table. FIG. 4 is a schematic flowchart for explaining the operation of the drawing apparatus. FIG. 5 is an explanatory diagram for explaining the operation of the drawing apparatus. FIG. 6 is a schematic flowchart for explaining the learning operation of the drawing apparatus. FIG. 7 is a schematic flowchart for explaining the drawing operation of the drawing apparatus.

  As shown in FIG. 1, the drawing apparatus 200 includes a spindle motor 10, a stepping motor 20, a feed screw 30, and an optical pickup unit 40. The drawing apparatus 200 includes a drive waveform generation unit 50 and a motor driver 51. The drawing apparatus 200 includes an address decoder 60, a position calculation unit 61, a difference calculation unit 62, an error table generation unit (error value writing unit) 63, an error table storage unit 64, a correction signal generation unit 65, a drive signal source 66, an addition A device 67, an actuator driver 68, a drawing data holding unit 69, a laser driver 70, and a controller 80.

  The drive unit (first drive unit) 110 illustrated in FIG. 1 is formed by the drive waveform generation unit 50 and the motor driver 51. Similarly, the error calculation unit 120 is formed by an address decoder 60, a position calculation unit 61, a difference calculation unit 62, and an error table generation unit 63. Similarly, the drive unit (second drive unit) 130 is formed by an error table storage unit 64, a correction signal generation unit 65, a drive signal source 66, an adder 67, and an actuator driver 68.

  As will be apparent from the description below, the drive unit 110 controls the stepping motor 20 to move the optical pickup unit 40 stepwise in the radial direction of the optical disc OPD. The error calculation unit 120 is a positional deviation between a preset target position (see the description below) and the position where the optical pickup unit 40 is actually moved by the first driving unit 110 toward the target position. An error value corresponding to the amount is calculated in correspondence with the target position. The second drive unit 130 displaces the lens in the optical pickup unit 40 according to the error value associated with the current target position in synchronization with the step movement of the optical pickup unit 40 by the first drive unit. More specific description will be given below.

  The spindle motor 10 rotates the optical disc OPD sandwiched between the lower plate 11 and the upper plate 12 according to the rotation of the rotary shaft 13. Note that the rotation of the spindle motor 10 is controlled by the controller 80.

  The stepping motor 20 is a normal magnetic motor. For example, the stepping motor 20 generates a driving force according to a two-phase driving signal.

  The feed screw 30 rotates according to the driving force generated by the stepping motor 20. As the feed screw 30 rotates, the optical pickup unit 40 moves to the left or right. As described above, the moving direction of the optical pickup unit 40 depends on the rotation direction of the feed screw 30. Further, the optical pickup unit 40 is engaged with the feed screw 30 via the engagement unit 45.

  The optical pickup unit 40 writes a digital signal on the data surface of the optical disc OPD by irradiating the data surface of the optical disc OPD with laser light. Further, the optical pickup unit 40 receives a reflected light from the optical disc OPD, and reads a digital signal from the data surface of the optical disc OPD. Further, the optical pickup unit 40 draws on the drawing surface of the optical disc OPD by irradiating the drawing surface of the optical disc OPD with laser light.

  FIG. 2 shows a specific configuration of the optical pickup unit 40. As shown in FIG. 2, the optical pickup unit 40 includes a light receiving unit 75, a light emitting unit 76, a magnetic force application unit (actuator) 72, and a lens (optical component) 73. As is clear from FIG. 2, these are housed in a common housing. The light irradiation unit 79 is formed by the light emitting unit 76 and the lens 73. In addition, the specific structure of the optical pick-up part 40 is arbitrary, and is not restricted to the structure shown in FIG.

  The light receiving unit 75 includes at least a light detection element such as a photodiode and a transimpedance circuit connected thereto. The light receiving unit 75 outputs a signal (for example, a voltage signal) having a value corresponding to the incident light intensity.

  The light emitting unit 76 is a light emitting element such as a laser diode. The light emitting unit 76 emits light having an intensity corresponding to the amount of drive current controlled by the laser driver 70.

  The magnetic force application unit 72 includes a coil 72a and a coil 72b. The amount of current flowing through each of the coils 72a and 72b is controlled by the actuator driver 68, thereby moving the lens 73 to the right or left.

  The lens 73 is an optical component that condenses the light emitted from the light emitting unit 76 on the optical disc OPD. The lens 73 is an optical component that guides reflected light from the optical disc OPD to the light receiving unit 75. The lens 73 moves to the right or left under the control of the magnetic force application unit 72.

  Again, returning to FIG.

  The address decoder 60 decodes the output signal from the light receiving unit 75 into address data (address signal).

  The position calculation unit 61 calculates a value indicating the position of the optical pickup unit 40 in the radial direction of the optical disc OPD based on the address data output from the address decoder 60. The value calculated by the position calculation unit 61 has a value corresponding to the distance between the initial position of the optical pickup unit 40 and the current position of the optical pickup unit 40.

  The difference calculation unit 62 compares the value input to the first input “a” with the value input to the second input “b”, and calculates the difference between the two. The value calculated by the position calculation unit 61 is input to the first input a of the difference calculation unit 62. A value set by the controller 80 is input to the second input b of the difference calculation unit 62.

  As will be described later, when the drawing apparatus 200 performs a learning operation, the following signals are input to the first input a and the second input b of the difference calculation unit 62, respectively. A signal having a value corresponding to the current position of the optical pickup unit 40 in the radial direction of the optical disk OPD (hereinafter sometimes simply referred to as the current position of the optical pickup unit) is input to the first input a of the difference calculation unit 62. The A signal having a predetermined value corresponding to a target position of the optical pickup unit 40 in the radial direction of the optical disc OPD (hereinafter sometimes simply referred to as a target position of the optical pickup unit) is input to the second input b of the difference calculation unit 62. Is done.

  A plurality of target positions are set in advance on the drawing surface of the optical disc OPD along the moving direction of the optical pickup unit 40. Therefore, the controller 80 sequentially sets a signal having a value corresponding to the target position as the predetermined value set to the second input b of the difference calculation unit 62.

  The difference calculator 62 calculates and outputs the difference between the two input signal values. By the difference calculation by the difference calculation unit 62, it is possible to detect how far the optical pickup unit 40 is currently positioned from the target position. The difference value (error value) calculated by the difference calculation unit 62 corresponds to the amount of deviation of the current position of the optical pickup unit 40 from the target position.

  The error table generation unit 63 temporarily holds the difference values sequentially output from the difference calculation unit 62 in the cache 63a. After the predetermined number of difference values are held in the cache 63a, the error table generation unit 63 writes the difference value data into the error table storage unit 64 at a predetermined timing in a batch or division.

  The error table storage unit 64 has an error table that stores the difference values in order. In other words, the error table storage unit 64 stores the above-described difference value in association with the above-described predetermined target position. The error table storage unit 64 is a non-volatile memory such as a flash memory.

  FIG. 3 shows a specific configuration of the error table. As shown in FIG. 3, the plurality of difference values are stored in the table in order by position number. A difference value corresponding to the number of target positions is stored in the error table. Each difference value is stored in the error table in association with the corresponding target position. Here, the above-described position number functions as an identification value for each target position.

  The correction signal generation unit 65 generates a correction signal according to the difference value held in the error table storage unit 64.

  The drive signal source 66 outputs a drive signal for displacing the lens 73.

  The adder 67 adds the drive signal and the correction signal. When both the correction signal and the drive signal are numerical signals, the adder 67 adds the values of both signals. The adder 67 outputs a signal of the added value (a voltage signal or the like corresponding to the added value). When both the correction signal and the drive signal are voltage signals, the adder 67 is formed by a node between the output of the correction signal generation unit 65 and the output of the drive signal source 66. The mode of displacement of the lens 73 is determined by the waveform of the added signal.

  The drive signal source 66, the error table storage unit 64, the correction signal generation unit 65, and the adder 67 function as a drive signal generation unit that generates a drive signal for moving the optical components in the optical pickup unit.

  The actuator driver 68 controls the magnetic force application unit 72 according to the input drive signal. For example, the actuator driver 68 controls the magnetic force application unit 72 according to the comparison result between the voltage signal output from the adder 67 and the reference voltage. Specifically, if the voltage signal from the adder 67 is equal to or higher than the reference voltage, the actuator driver 68 controls the magnetic force application unit 72 to move the lens 73 to the left. If the voltage signal from the adder 67 is less than the reference voltage, the actuator driver 68 controls the magnetic force application unit 72 to move the lens 73 to the right. Thus, the movement amount of the lens 73 is in accordance with the voltage difference between the voltage signal from the adder 67 and the reference voltage.

  The drawing data holding unit 69 outputs the held drawing data. The laser driver 70 drives the light emitting unit 76 based on the input drawing data. The drawing data holding unit 69 outputs the holding drawing data when the control signal sig4 from the controller 80 is input. A desired image is drawn on the drawing surface of the optical disc OPD in accordance with the drawing data held in the drawing data holding unit 69.

  The drive waveform generation unit 50 generates a drive waveform. For example, the drive waveform generation unit 50 generates a sine wave (sin / cos) whose phase is shifted by 90 degrees. The motor driver 51 drives the stepping motor 20 according to the input driving waveform. The drive waveform generator 50 generates a drive signal for sequentially moving the optical pickup unit 40 in order to sequentially arrange the optical pickup unit 40 at each of a plurality of preset target positions on the drawing surface of the optical disc OPD. Functions as a drive signal generation unit.

  The controller 80 includes a control signal sig1 for the drive waveform generation unit 50, a control signal sig2 for the correction signal generation unit 65, a control signal sig3 for the drive signal source 66, a control signal sig4 for the drawing data holding unit 69, and a control signal sig5 for the laser driver. Is output.

  Here, the connection relationship between the above-described elements will be described. The output of the light receiving unit 75 is connected to the input of the address decoder 60. The output of the address decoder 60 is connected to the input of the position calculation unit 61. The output of the position calculation unit 61 is connected to the first input a of the difference calculation unit 62. A signal set by the controller 80 is connected to the second input b of the difference calculation unit 62. The output of the difference calculation unit 62 is connected to the input of the error table generation unit 63. The output of the error table generation unit 63 is connected to the input of the error table storage unit 64. The output of the error table storage unit 64 is connected to the input of the correction signal generation unit 65. The output of the correction signal generator 65 is connected to the input of the adder 67. The output of the drive signal source 66 is connected to the adder 67. The output of the adder 67 is connected to the actuator driver 68. The output of the drawing data holding unit 69 is connected to the laser driver 70. The output of the laser driver 70 is connected to the light emitting unit 76. The output of the drive waveform generator 50 is connected to the input of the motor driver 51. The output of the motor driver 51 is connected to the stepping motor 20.

  The operation of the drawing apparatus 200 will be described with reference to FIG.

  As shown in FIG. 4, the drawing apparatus 200 first performs a learning operation (S100). By this learning operation, a necessary difference value is stored in the above error table.

  During the learning operation, the optical disk OPD is arranged so that the data surface of the optical disk OPD faces the optical pickup unit 40 as shown in FIG. The optical pickup unit 40 moves from the inner periphery side to the outer periphery side of the optical disc OPD. The current position of the optical pickup unit 40 is detected based on reading an address signal from the data surface of the optical disc OPD. The vertical stripe pattern of the optical disk OPD shown in FIG. 5A schematically shows each track formed on the optical disk OPD.

  Further, as is well known, a spirally formed track is formed on the data surface of the optical disc OPD. A plurality of data storage areas are formed in the track. An address signal is assigned in advance to the data storage area of the track.

  Next, the drawing apparatus 200 executes a drawing operation (S200). In the drawing operation, the optical pickup unit 40 is arranged such that the drawing surface of the optical disc OPD faces the optical pickup unit 40 as shown in FIG. The optical pickup unit 40 moves from the inner periphery side to the outer periphery side of the optical disc OPD.

  During the above-described drawing, the drawing apparatus 200 generates a correction signal based on the difference value stored in the error table, and corrects the signal value of the drive signal output from the drive signal source 66 with this correction signal. By moving the optical pickup unit 40 toward the next target position by the stepping motor 20 and then displacing the lens 73 by the corrected drive signal, the displacement of the optical pickup unit 40 can be effectively corrected. More specifically, the position of the lens 73 is entirely shifted by the correction signal, and the spot position of the laser beam formed on the drawing surface of the optical disk OPD is changed. Therefore, the arrangement of the optical pickup unit 40 by the stepping motor 20 is changed. The deviation can be effectively corrected.

  The above points will be supplemented with reference to FIG.

  First, it is assumed that the optical pickup unit 40 is disposed at the position p0. The next target position of the optical pickup unit 40 is p10. However, in actuality, it is assumed that the optical pickup unit 40 has moved only to the position p9 due to product variations and the like. In this case, the optical pickup unit 40 is displaced by the amount corresponding to the interval W1 between the current position p9 and the target position p10. If the optical pickup unit 40 performs drawing in this state, the region to be actually drawn is formed on the inner peripheral side than the target region.

  The next target position of the optical pickup unit 40 is assumed to be p20. However, it is assumed that the optical pickup unit 40 has actually moved past the target position p20 to the position p21 due to product variations and the like. In this case, the optical pickup unit 40 is displaced by the amount corresponding to the interval W2 between the current position p21 and the target position p2. When the optical pickup unit 40 performs drawing in this state, the area to be actually drawn is formed on the outer peripheral side than the target area.

  In the present embodiment, the placement errors W1 and W2 described above are detected in advance by the drawing apparatus 200 executing a learning operation. At the time of drawing, the drawing apparatus 200 shifts the position of the lens 73 in the optical pickup unit 40 according to the value indicating the placement error obtained by learning. In the present embodiment, a correction signal is generated according to an error value indicating an arrangement error obtained by learning, and a drive signal for displacing the lens 73 is corrected by this correction signal. As described above, by shifting the position of the lens according to the degree of the displacement detected in advance at the time of drawing, the influence of the displacement of the optical pickup unit 40 by the stepping motor 20 can be effectively corrected. Since the error table once generated is stored in the nonvolatile memory, the drawing apparatus 200 does not need to execute the learning operation every time the drawing operation is performed.

  The description will be supplemented with reference to FIG. When the optical pickup unit 40 is disposed at the position p9, the drawing apparatus 200 can perform the same drawing as when the optical pickup unit 40 is at the target position p10 by shifting the lens 73. In addition, when the optical pickup unit 40 is disposed at the position p21, the drawing apparatus 200 can perform the same drawing as when the optical pickup unit 40 is at the target position p20 by shifting the lens 73. Thus, by shifting the lens 73 at the time of drawing, the influence of the displacement of the optical pickup unit 40 due to the stepping motor 20 can be effectively corrected. Note that shifting the lens 73 is synonymous with displacing the lens 73.

  With reference to FIG. 6, the learning operation by the drawing apparatus 200 will be described. Note that the optical disk OPD is arranged as shown in FIG.

  First, the controller 80 drives the spindle motor 10 (S50). In response to the control signal sig5 from the controller 80, the laser driver 70 drives the light emitting unit 76. The light emitting unit 76 irradiates the data surface of the optical disc OPD with laser light in accordance with control by the laser driver 70.

  Next, the optical pickup unit 40 is set to the initial position (S51). Specifically, the drive waveform generation unit 50 generates a drive waveform according to the control signal sig 1 from the controller 80, and outputs this to the motor driver 51. The motor driver 51 drives the stepping motor 20 according to the input driving waveform. The driving force generated by the stepping motor 20 in this way is transmitted to the optical pickup unit 40 via a power transmission system such as the feed screw 30. And the optical pick-up part 40 is arrange | positioned in the initial position.

  Next, the optical pickup unit 40 is moved toward the target position (S52). Specifically, the drive waveform generation unit 50 generates a drive waveform according to the control signal sig 1 from the controller 80, and outputs this to the motor driver 51. The motor driver 51 drives the stepping motor 20 according to the input driving waveform. The driving force generated by the stepping motor 20 in this way is transmitted to the optical pickup unit 40 through the power transmission system. Then, the optical pickup unit 40 moves by a predetermined interval toward the target position. When the movement is completed, focus servo and track servo are applied in order to obtain an address from the data surface of the optical disk OPD.

  Next, each step of acquiring an address, calculating a moving distance, calculating a difference value, and writing to the cache is executed in this order (S53).

  The drawing apparatus 200 executes address acquisition (S53a). Specifically, the reflected light from the data surface of the optical disk OPD is received by the light receiving unit 75, and the output signal from the light receiving unit 75 is converted into address data by the address decoder 60. In this way, an address indicating the current position of the optical pickup unit 40 is acquired.

  The drawing apparatus 200 next calculates the movement distance (S53b). Specifically, the position calculation unit 61 calculates the movement distance of the optical pickup unit 40 based on the address data output from the address decoder 60. The moving distance is the length (distance) that the optical pickup unit 40 has moved from the initial position. The moving distance is calculated by subtracting a value indicating the initial position of the optical pickup unit 40 from a value indicating the current location of the optical pickup unit 40. It is assumed that the address indicating the position of the optical pickup unit 40 is acquired when the optical pickup unit 40 is placed at the initial position in S51 described above.

  The drawing apparatus 200 next calculates a difference value (S53c). Specifically, the difference calculation unit 62 calculates a difference value between the value calculated by the position calculation unit 61 and a predetermined value. The predetermined value connected to the second input b of the difference calculation unit 62 has a value corresponding to the distance between the initial position of the optical pickup unit 40 and the current target position of the optical pickup unit 40. By subtracting the value calculated by the position calculation unit 61 from the predetermined value, it is possible to calculate the amount of displacement of the current position of the optical pickup unit 40 with respect to the target position.

  The drawing apparatus 200 writes the difference value calculated as described above to the cache (S53d).

  Next, the drawing apparatus 200 determines whether the outer peripheral position has been reached (S54). Here, the number of target positions is known in advance. Accordingly, the drawing apparatus 200 determines whether or not the optical pickup unit 40 has reached the final target position by determining whether or not the number of step movements of the optical pickup unit 40 has reached a predetermined number.

  If the optical pickup unit 40 has not reached the final target position, the process moves to step S52 described above. By repeating this, a plurality of difference values are held in the cache 63a of the error table generation unit 63 corresponding to the number of movements (target position number) of the optical pickup unit 40.

  When the optical pickup unit 40 has reached the final target position, the error table generating unit 63 of the drawing apparatus 200 stores the error table by batching or dividing the difference values stored in the cache 63a of the error table generating unit 63. Write to the error table of the unit 64. Then, the learning operation of the drawing apparatus 200 ends.

  Upon completion of the learning operation, a difference value corresponding to the number of target positions is stored in the error table. This difference value indicates the amount of misalignment between a preset target position and the current position of the optical pickup unit actually moved by the stepping motor 20.

  A drawing operation of the drawing apparatus 200 will be described with reference to FIG.

  First, the drawing apparatus 200 moves the optical pickup unit 40 toward a predetermined target position (S60). Specifically, the drive waveform generation unit 50 generates a drive waveform according to the control signal sig 1 from the controller 80, and outputs this to the motor driver 51. The motor driver 51 drives the stepping motor 20 according to the input driving waveform. The driving force generated by the stepping motor 20 in this way is transmitted to the optical pickup unit 40 through the power transmission system. Then, the optical pickup unit 40 moves by a predetermined interval and moves toward a predetermined target position.

  Next, the drawing apparatus 200 generates a correction signal (S61). Specifically, the correction signal generation unit 65 refers to the error table stored in the error table storage unit 64 according to the control signal sig2 from the controller 80, and calculates the difference value corresponding to the current target position as the error table. Lead from. Then, the correction signal generation unit 65 generates a correction signal having a value corresponding to the read difference value.

  Next, the drawing apparatus 200 executes drive signal correction (S62). Specifically, the adder 67 adds the drive signal output from the drive signal source 66 and the correction signal generated by the correction signal generation unit 65 in accordance with the control signal sig3 from the controller 80. In this way, the drive signal output from the drive signal source 66 is corrected by the correction signal generated by the correction signal generation unit 65, and the corrected drive signal is input to the actuator driver 68.

  When the output of the adder 67 is connected to the actuator driver 68, the lens is displaced accordingly. Specifically, the actuator driver 68 controls the magnetic force application unit 72 according to the input drive signal to move the lens 73. By displacing the position of the lens 73 based on the corrected drive signal, it is possible to effectively eliminate the influence of the displacement of the optical pickup unit 40.

  Next, the drawing apparatus 200 performs drawing (S63). Specifically, the controller 80 outputs the control signal sig4 to the drawing data holding unit 69. In response to the control signal sig4, the drawing data holding unit 69 outputs the held drawing data to the laser driver 70. The laser driver 70 controls the light emitting unit 76 based on the input drawing data. In this way, a desired image is formed on the track on the drawing surface of the optical disc OPD.

  Next, the drawing apparatus 200 determines whether or not the outer peripheral position has been reached (S64). Specifically, the controller 80 determines whether or not the optical pickup unit 40 has reached the final target position by determining whether or not the number of step movements of the optical pickup unit 40 has reached a predetermined number.

  If the optical pickup unit 40 has not reached the final target position, the process moves to step S60 described above. Specifically, the optical pickup unit 40 is moved toward the next target position (S60). By repeating this, a desired image is drawn on the drawing surface of the optical disc.

  When the optical pickup unit 40 has reached the final target position, the drawing operation of the drawing apparatus 200 ends.

  As is clear from the above description, in this embodiment, the placement error of the optical pickup unit 40 by the stepping motor 20 is detected in advance by the learning operation by the drawing apparatus 200. The drawing apparatus 200 shifts the lens 73 in the optical pickup unit 40 according to an error value indicating an arrangement error of the optical pickup unit 40 detected by learning at the time of drawing. Since the spot position of the laser beam on the drawing surface is changed according to the shift of the lens 73, the influence of the displacement of the optical pickup unit 40 by the stepping motor 20 can be effectively eliminated. That is, even if no index indicating position information is set on the drawing surface of the optical disc, the image quality of the finally drawn image is reduced without depending on the feeding accuracy of the feeding mechanism itself of the optical pickup unit. Can be suppressed.

  A specific method for calculating the error value is arbitrary. The error value may be obtained based on the count of the number of cross tracks.

[Second Embodiment]
A second embodiment of the present invention will be described with reference to FIGS. FIG. 8 is a schematic flowchart for explaining the learning operation of the drawing apparatus. FIG. 9 is an explanatory diagram for explaining an example of calculation processing by the error table generation unit.

  In the present embodiment, the error table generation unit 63 performs arithmetic processing on a plurality of difference values held in the cache 63a. In other words, the error table generation unit 63 also functions as a calculation execution unit that executes a calculation on a plurality of difference values held in the cache 63 (error calculation execution unit). The specific content of the arithmetic processing is arbitrary. For example, the error table generator 63 leaves the frequency component that has the greatest influence on the image quality degradation of the drawing result, and removes unnecessary frequency components.

  As shown in FIG. 8, when it is determined in step S54 that the optical pickup unit 40 has reached the outer peripheral position, the error table generation unit 63 of the drawing apparatus 200 performs an operation on a predetermined number of difference values ( S56).

  For example, the error table generation unit 63 obtains a moving average of the required number of difference values held in the cache. Then, the error table generation unit 63 subtracts the moving average value calculated from each of the necessary number of difference values held in the cache to remove the low frequency component. In this way, the distribution of difference values as shown in FIG. 9A is converted into the distribution of difference values from which low frequency components are removed as shown in FIG. 9B.

  In this way, by removing the low frequency component, it is possible to prevent the absolute value of the placement error from becoming too large and making correction impossible only by the lens shift.

[Third Embodiment]
A third embodiment of the present invention will be described with reference to FIG.

  In the present embodiment, a process of thinning out some difference values after removing high-frequency components from the difference values obtained in the second embodiment is added. Specifically, for example, FIG. 9B, which is the difference value distribution obtained by the second embodiment, is passed through FIG. 9C, which is the difference value distribution from which high-frequency components are removed, and the error table generation unit. 63 indicates that a process of thinning out the difference values held in the cache 63a is executed to obtain FIG. 9D, which is a distribution in which some difference values are thinned out.

  When the table is thinned, the correction amount of the thinned target position is determined by performing linear interpolation using the data of the adjacent target position at the time of drawing execution S61.

  As described above, the amount of memory required for the error table storage unit can be suppressed by performing thinning out on the data.

  In the present embodiment, the description is made on the assumption that the low-frequency component shown in the second embodiment is removed, but it may be performed after the first embodiment.

  The technical scope of the present invention is not limited to the above-described embodiment. The type of drawing object (optical disk) is arbitrary. The direction in which the lens is displaced is arbitrary. Optical components other than the lens may be displaced. The connection relationship between the functional blocks can be modified as appropriate. The drawing apparatus may be realized by partially incorporating program control. That is, the drawing apparatus may be realized only by hardware, or may be realized by controlling hardware by software. The drive signal generation device may be a semiconductor integrated circuit, or may be realized by hardware control by software (sequentially executing a program by a CPU core of a computer).

1 is a block diagram illustrating a configuration of a drawing apparatus according to a first embodiment of the present invention. It is explanatory drawing which shows the structure of the optical pick-up part concerning the 1st Embodiment of this invention. It is explanatory drawing which shows the structure of the error table concerning the 1st Embodiment of this invention. It is a schematic flowchart for demonstrating operation | movement of the drawing apparatus concerning the 1st Embodiment of this invention. It is explanatory drawing for demonstrating operation | movement of the drawing apparatus concerning the 1st Embodiment of this invention. It is a schematic flowchart for demonstrating learning operation | movement of the drawing apparatus concerning the 1st Embodiment of this invention. It is a schematic flowchart for demonstrating drawing operation | movement of the drawing apparatus concerning this invention. It is a schematic flowchart for demonstrating the learning operation | movement of the drawing apparatus concerning the 2nd and 3rd embodiment of this invention. It is explanatory drawing for demonstrating an example of the arithmetic processing by the error table production | generation part concerning the 2nd and 3rd embodiment of this invention.

Explanation of symbols

200 Drawing device 110 First drive unit 120 Error calculation unit 130 Second drive unit

80 controller

10 Spindle motor 20 Stepping motor 30 Feed screw 40 Optical pickup

50 Drive waveform generator 51 Motor driver

60 address decoder 61 position calculation unit 62 difference calculation unit 63 error table generation unit 64 error table storage unit 65 correction signal generation unit 66 drive signal source 67 adder 68 actuator driver 69 drawing data holding unit 70 laser driver

72 Magnetic application unit 73 Lens 75 Light receiving unit 76 Light emitting unit 79 Light irradiation unit

Claims (9)

A light irradiation unit that irradiates light onto the drawing surface of the drawing object via an optical component;
A first driving unit for step-moving the light irradiation unit to sequentially arrange the light irradiation unit at each of a plurality of preset target positions on the drawing surface;
A light receiving unit that moves with the light irradiating unit as the light irradiating unit is stepped by the first driving unit;
An error value of a value corresponding to the amount of positional deviation between the arrangement positions of the light irradiation unit actually moved by the first driving unit toward the target position is made to correspond to each of the plurality of target positions. An error calculating unit to calculate,
The error associated with the current target position of the light irradiation unit in synchronization with the step movement of the light irradiation unit by the first driving unit for disposing the light irradiation unit at each of the plurality of target positions. A second drive unit that displaces the optical component according to a value;
Equipped with a,
The error calculator is
A decoding unit that converts an output signal from the light receiving unit into an address signal;
A position calculation unit that calculates a value indicating the current position of the light irradiation unit from the address signal output from the decoding unit;
A difference calculation unit for calculating a difference value between the value calculated by the position calculation unit and a preset value corresponding to the current target position;
At least with Ru drawing device.   The drawing apparatus according to claim 1, wherein the second driving unit adds a correction signal having a signal value corresponding to the error value to a driving signal for displacing the optical component. The second driving unit includes:
An error value storage unit for storing a plurality of error values;
A correction signal generation unit that generates the correction signal according to the error value stored in the error value storage unit;
A drive signal source for generating the drive signal;
The drawing apparatus according to claim 2, further comprising: The drawing apparatus according to claim 3 , wherein the error calculation unit further includes an error value writing unit that writes the difference value calculated by the difference calculation unit as the error value in the error value storage unit. . The drawing apparatus according to claim 4 , wherein the error calculation unit further includes an error calculation execution unit that executes calculation processing on the difference value written or to be written in the error value storage unit. . Drawing device according to any one of claims 1 to 5, further comprising a controller for controlling the synchronization between the first driving unit and the second driving unit. The error calculating unit, a drawing device according to any one of claims 1 to 6, wherein calculating the plurality of error values based on the output from the light receiving portion. The drawing object has the drawing surface on one side, according to any one of claims 1 to 7 tracks on the other surface is characterized in that an optical disc having a spirally formed data surface Drawing device. A first drive signal for sequentially moving the optical pickup unit in order to sequentially arrange the optical pickup unit at each of a plurality of preset target positions on the drawing surface of the drawing object, and an optical component in the optical pickup unit. A drive signal generation device for generating a second drive signal for movement,
A first drive signal generator for generating the first drive signal;
Based on the output of the light receiving unit in the optical pickup unit, a plurality of error values corresponding to the amount of positional deviation between the target position and the position of the optical pickup unit actually moved toward the target position are set. An error calculation unit for calculating each of the target positions,
A signal value corresponding to the error value associated with the current target position of the optical pickup unit in synchronization with the generation of the first drive signal for disposing the optical pickup unit at each of the plurality of target positions. A second drive signal generation unit for generating the second drive signal;
Equipped with a,
The error calculator is
A decoding unit that converts an output signal from the light receiving unit into an address signal;
A position calculation unit that calculates a value indicating the current position of the light irradiation unit from the address signal output from the decoding unit;
A difference calculation unit for calculating a difference value between the value calculated by the position calculation unit and a preset value corresponding to the current target position;
At least with Ru drive signal generating device.

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