JP4816559B2 - Image reading device - Google Patents

Description

  The present invention relates to a technique for reading an image drawn on an optical disc.

In an optical disc such as a CD-R (Compact Disc-Recordable), CD-RW (Compact Disc Rewritable) or DVD-R (Digital Versatile Disk-Recordable), the contents of recorded data cannot be identified with the naked eye. Unless labeling or printing is performed, it is difficult to identify each optical disk from the appearance of the disk itself. In view of this, a technique has been proposed in which an optical disk can be easily identified by its appearance by drawing characters, symbols, figures, or patterns on the optical disk itself (see, for example, Patent Document 1 and Patent Document 2).
JP 2006-155812 A JP 2003-16649 A

By the way, there are many requests for editing an image drawn on the optical disk or adding an image, but in this case, it is preferable if an image already drawn on the optical disk can be grasped.
The present invention has been made under the above-described background, and an object thereof is to provide a technique capable of reading an image drawn on an optical disc.

An image reading apparatus according to a preferred aspect of the present invention includes: a rotating unit that rotates an optical disc; a light irradiating unit that irradiates an optical disc that is movable in the radial direction of the optical disc and is rotated by the rotating unit; Each time the optical disk is rotated a plurality of times by the rotating means, the light irradiating means is arranged in a dot arrangement. The feed means for moving the disk in the substantially radial direction by an amount corresponding to the pitch in the radial direction, and the irradiation position of the laser light is vibrated in the radial direction of the optical disk, so that the irradiation path of the laser light on the optical disk Differently, the irradiation position control means for controlling the irradiation position operation means, and the optical disk is irradiated by the light irradiation means. The reflected light of the laser beam is received for each predetermined dot area, the gradation degree specifying means for specifying the gradation degree for each dot area according to the received reflected light, and the gradation degree specifying means specified by the gradation degree specifying means Output means for outputting data indicating the gradation of each dot area.

In the above-described aspect, the irradiation position operation means operates the irradiation position of the laser beam according to the voltage of the vibration signal, and the irradiation position control means has a constant amplitude and a constant when the optical disk overlaps a plurality of turns. The vibration signal having a frequency may be generated so that the phase thereof is different for each lap .

  Further, in the above-described aspect, a feed width information acquiring unit that acquires feed width information indicating a feed width is provided, and the feed unit reads from a radial reading start position indicated by the position information acquired by the position information acquiring unit. Until the end position, the light irradiation means may be moved in the radial direction by the feed width indicated by the feed width information acquired by the feed width information acquisition means each time the optical disk rotates a plurality of times.

  Further, in the above-described aspect, the image processing apparatus includes dot area information storage means for storing dot area information indicating the dot area, and the gradation level specifying means is a reflected light of the laser light irradiated on the optical disc by the irradiation position control means. May be received for each dot area indicated by the dot area information stored in the dot area storage means, and the gradation for each dot area may be specified according to the received reflected light.

  Further, in the above-described aspect, the image processing apparatus further includes dot area information acquisition means for acquiring dot area information indicating the dot area, and the gradation level specifying means is a reflected light of the laser light irradiated on the optical disc by the irradiation position control means. May be received for each dot area indicated by the dot area information acquired by the dot area information acquisition means, and the gradation level for each dot area may be specified according to the received reflected light.

  According to the present invention, an image drawn on an optical disk can be read.

  An optical disc recording apparatus 1 according to the present embodiment has a function (data recording / reproduction function) for recording / reproducing data such as music data on an optical disc, and a function (drawing) for drawing an image that a user can visually recognize on the optical disc. Function) and a function of reading an image drawn on the optical disk (image reading function). In the following description, the configuration of the optical disc itself will be described first, and then the optical disc recording apparatus 1 will be described.

(1) Configuration (1-1) Configuration of Optical Disc FIG. 1 shows an example of a cross-sectional view of an optical disc 100 according to this embodiment. The optical disc 100 is, for example, a DVD-R, CD-R, CD-R / DVD-R mixed type optical disc. As shown in FIG. 1, in the optical disc 100, a polycarbonate layer 101, a data recording layer 103, a semi-transparent layer 104, an intermediate layer 105, a drawing layer 106, and a semi-transparent layer are sequentially arranged from the recording surface D to the label surface L. 107 and a polycarbonate layer 108 are laminated. The thickness of the optical disc 100 is approximately 1.2 (mm), of which the polycarbonate layer 101 and the polycarbonate layer 108 occupy about 0.6 (mm), respectively, from the data recording layer 103 to the translucent layer 107. The thickness d is very small compared to the overall thickness.

  A spiral groove (guide groove) 102 is formed on the recording surface D side of the data recording layer 103. At the time of data recording, the position of the objective lens 13 is adjusted to an appropriate position in the direction of the arrow P, and the laser beam is focused on the data recording layer 103 based on the reflected light from the semitransparent layer 104. Then, a laser beam having an intensity corresponding to the data to be recorded is irradiated along the groove 102 of the data recording layer 103. At this time, pits corresponding to the data length are formed at the locations irradiated with the laser beam, and data recording is thereby performed. In the case where the recorded data is read and reproduced, data reproduction is performed by irradiating the groove 102 with laser light having a weaker intensity than that during recording and detecting the intensity of the reflected light (return light). Realized.

  The drawing layer 106 is formed of a substance that changes color when irradiated with laser light having a certain intensity. At the time of drawing, the position of the objective lens 13 is adjusted to an appropriate position in the direction of the arrow P, and the laser beam la is focused on the drawing layer 106 based on the reflected light from the semi-transparent layer 107. When the laser beam la having a certain intensity is irradiated, the region of the drawing layer 106 irradiated with the laser beam la changes color. An image that can be visually recognized by the user is formed by the discolored area and the undiscolored area. FIG. 1 shows a case where the focused laser beam la is irradiated on the drawing layer 106. Note that reading a drawn image is realized by irradiating the drawing layer 106 with a laser beam having a intensity lower than a predetermined intensity that is weaker than that at the time of drawing and detecting the intensity of the reflected light.

(1-2) Overall Configuration of System FIG. 2 is a block diagram illustrating an example of the configuration of the system according to the present embodiment. As shown in FIG. 2, the system according to the present embodiment is configured by connecting the host device 200 and the optical disc recording apparatus 1 in a state where they can communicate with each other. The optical disc recording apparatus 1 may be in a format built in the host device 200 or an external format. An optical disc 100 is loaded in the optical disc recording apparatus 1. The spindle motor 11 is a rotating unit that rotates the optical disc 100. The spindle servo 12 controls the rotation of the spindle motor 11 at a constant linear velocity during recording and reproduction (CLV control), and controls the rotation number at the time of drawing and image reading (CAV control). The optical pickup 14 is a light irradiation unit that is movable in the radial direction of the optical disk 100 and irradiates the optical disk 100 rotated by the spindle motor 11 with laser light. The optical pickup 14 is moved in the radial direction (left and right direction in the figure) of the optical disc 100 by a feed mechanism 16 such as a feed screw driven by a stepping motor 15. The motor driver 17 drives the stepping motor 15 based on a command from the system control unit 19.

  A focus servo 18 performs focus control of the optical pickup 14. The tracking servo 20 performs tracking servo control of the optical pickup 14 during data recording and reproduction. However, the tracking servo control is turned off during drawing and image reading. The laser driver 22 controls the laser power to an instructed value. An ALPC (Automatic Laser Power Control) circuit 21 controls the laser power to a specified value. The optical pickup 14 controls the intensity of the laser beam when the laser driver 22 drives the laser diode of the optical pickup 14 based on a command from the system control unit 19 and a light reception signal from the optical pickup 14.

  The vibration signal generator 30 generates a vibration signal during drawing and image reading, and supplies the vibration signal to a tracking actuator (not shown) of the optical pickup 14 to vibrate the objective lens 13. In this embodiment, an AC signal generated such that the irradiation position of the laser beam vibrates in the radial direction, for example, a triangular signal is supplied to the tracking actuator. As a result, the laser light is vibrated in the radial direction of the optical disc 100 with an amplitude larger than the unit feed amount by the 1 micro-step operation of the optical pickup 14. By this vibration operation, the laser light can scan the drawing layer while meandering with a width wider than the unit feed amount of the optical pickup 14. In this embodiment, the optical disc recording apparatus 1 performs the vibration operation while keeping the optical pickup 14 at substantially the same position in the radial direction at the time of drawing and image reading, and the same while rotating the optical disc 100 a plurality of times. Overwrite and overread images. Hereinafter, the number of times of overwriting is referred to as “Nr”.

  The memory 28 stores image reading conditions set in advance in the optical disc recording apparatus 1 and image reading conditions that can be set by the operator. The “predetermined image reading conditions” include “the feed amount of the optical pickup 14 by one full step operation of the stepping motor 15 used for calculating the unit feed amount for transporting the optical pickup 14 in the radial direction of the optical disc 100”. “L” and “the number M of microstepping operations of the stepping motor 15” are stored. As the “image reading conditions that can be set by the operator”, information on a plurality of types of “image reading modes” in which “rotation speed of the optical disk” and “encoding speed of image data by the encoder 23” are combined, The “reading start position R0” and “reading end position R1” in the radial direction of the optical disk, and the above-mentioned “number of times of repeated reading Nr” are stored.

  The encoder 23 encodes the recording data into a format corresponding to the format of the optical disc 100 at the time of data recording. The laser driver 22 modulates the laser beam according to the encoded recording data, and records this recording data on the data recording layer 103 of the optical disc 100 as pits. On the other hand, at the time of drawing, the encoder 23 encodes the image data to generate a pulse signal whose duty changes according to the gradation data of the pixels (dots) constituting the image data. The laser driver 22 modulates the laser light in accordance with the pulse signal whose duty changes, changes the visible light characteristic of the drawing layer 106 of the optical disc 100 (that is, changes the color), and performs drawing with monochrome multi-tone. The decoder 25 performs data reproduction by EFM demodulating a received light signal corresponding to the return light received by the optical pickup 14 during data reproduction.

  An LPF (low-pass filter) 26 performs a low-pass filter process on the light reception signal corresponding to the return light received by the optical pickup 14 during image reading. The comparator 27 compares the level of the signal output from the LPF 26 with a predetermined threshold, and outputs an “H” level or “L” level pulse signal to the system control unit 19 according to the comparison result. To do. Specifically, for example, when the level of the signal output from the LPF 26 is equal to or higher than the threshold value, the comparator 27 outputs an “H” level signal to the system control unit 19 while the signal level is reduced. If it is smaller than the threshold value, an “L” level signal may be output to the system controller 19. The N divider 29 divides the N-pulse pulse signal FG output from the spindle motor 11 by N to generate a 1-pulse pulse signal FG ′ per rotation. The number of rotations of the optical disc 100 can be detected by the pulse signal FG ′.

  Here, signal processing relating to image reading will be described with reference to FIG. FIG. 3 is a time chart of various signals at the time of image reading. FIG. 3 shows a time chart of various signals when the optical disc 100 rotates once. In the figure, (a) shows the waveform of the received light signal RF output from the optical pickup 14 to the LPF 26. (B) shows the waveform of the light reception signal RF ′ output from the LPF 26 after low-pass filter processing is applied to the light reception signal RF. (C) shows the waveform of the pulse signal MIR obtained by converting the light reception signal RF ′ by the comparator 27. (D) shows the waveform of the pulse signal FG output from the spindle motor 11 to the N frequency divider 29. (E) shows the waveform of the pulse signal FG ′ obtained by dividing the pulse signal FG by N. As shown in FIGS. 3A to 3C, the received light signal RF from the optical pickup 14 is set to the “H” level when the intensity is equal to or higher than a predetermined threshold, In this case, it is set to “L” level.

  The system control unit 19 determines whether the pulse signal MIR output from the comparator 27 is “H” level or “L” level for each predetermined dot area. Since the image drawn on the surface of the optical disc 100 has different reflectance between the discolored portion and the other portions, it is determined whether or not the dot region has been discolored by referring to the intensity of the reflected light. can do. The system control unit 19 writes the information “1” indicating that the color is not changed in the memory 28 for the dot area where the pulse signal MIR is “H” level, while the level of the pulse signal MIR is “L” level. For a certain dot area, information “0” indicating that the color is changed is written in the memory 28.

  Here, in this embodiment, a dot area for reading an image from the optical disc 100 will be described with reference to FIG. As shown in FIG. 4A, in the optical disc 100, sectors are arranged in a concentric circle from the inner circumference to the outer circumference from one row to m rows, and further, one column at a certain angle in the clockwise direction of the optical disc 100. To n rows are arranged on the radiation. Each sector has a region equally divided into 25 in the circumferential direction, as shown in FIG. 4B. In this embodiment, this one area corresponds to a dot of the image. Therefore, in this embodiment, the dots are arranged in m rows × 25 · n columns.

  In this embodiment, a dot is displayed as binary values of white or black, and 1 byte (8 bits) is assigned as dot data indicating monochrome of one dot. Here, “0” indicates a black dot, while other than “0” indicates a white dot. For each dot area described above, the system control unit 19 determines whether or not the dot area is discolored. If the dot area is discolored, a signal indicating this ("0" in this embodiment) is sent. On the other hand, when the color is not changed, a signal indicating this (in this embodiment, “1”) is written in the memory 28. In the following description, for convenience of explanation, an information group of “0” or “1” for each dot area that the system control unit 19 writes in the memory 28 will be referred to as “pixel column data”.

  Returning to the description of FIG. The host device 200 is used to exchange data with the optical disc recording apparatus 1, a control unit 201 having a CPU (Central Processing Unit), a storage unit 202 that stores a computer program executed by the control unit 201, and the like. And a communication unit 203. The host device 200 transmits a command from the operator to the optical disc recording device 1. This command is transmitted to the system control unit 19 via the interface 10. The system control unit 19 sends a command corresponding to the command to each circuit in the optical disc recording apparatus 1 to execute the corresponding operation. For example, at the time of data recording, the host device 200 transmits recording data to the optical disc recording apparatus 1. This recording data is received by the interface 10 of the optical disc recording apparatus 1 and written into the buffer memory 24 by the system control unit 19. Then, the system control unit 19 reads the recording data from the buffer memory 24 and supplies it to the encoder 23. The encoder 23 performs the above-described encoding process and supplies it to the laser driver 22. At the time of data reproduction, data reproduced by the decoder 25 is transferred to the host device 200 via the interface 10. On the other hand, at the time of drawing, the host device 200 transmits image data to the optical disc recording apparatus 1. This image data is received by the interface 10 and written into the buffer memory 24 by the system control unit 19. The system control unit 19 reads the image data from the buffer memory 24 and supplies it to the encoder 23. On the other hand, when reading an image, the system control unit 19 stores the pixel column data in the buffer memory 24, and the stored pixel column data is transferred to the host device 200 via the interface 10. The display device 300 includes a liquid crystal display and the like, and is a display unit that displays an image corresponding to data supplied from the host device 200.

(2) Operation Next, the operation of the system described above will be described. When the optical disc 100 is inserted into the optical disc recording apparatus 1, the system control unit 19 determines whether or not a command instructing some processing is received from the host device 200. When receiving the command, the system control unit 19 determines what processing the received command is to instruct. If the command is not a command for instructing image reading, the system control unit 19 executes processing (data recording operation, reproduction operation, or drawing operation) instructed by the command. Note that the data recording operation and the reproducing operation with respect to the optical disc 100 are the same as those in the prior art, and thus detailed description thereof is omitted.

  Next, the operation when an image reading operation is instructed will be described with reference to the flowchart shown in FIG. First, the system control unit 19 secures a pixel column data storage area for storing pixel column data in the buffer memory 24, and sets the value of each data in the secured pixel column data storage area to “0”. The pixel column data storage area is initialized (step S1). Next, the system control unit 19 controls the spindle servo 12, drives the spindle motor 11 by CAV control, and rotates the optical disc 100 (step S2).

  Next, the system control unit 19 causes the ALPC circuit 21 to start controlling the laser power. Thereby, the ALPC circuit 21 sets the laser power to the intensity for image reading. The optical pickup 14 emits laser light with a set laser power. Further, the system control unit 19 controls the focus servo 18 to perform the focus control of the optical pickup 14 (step S3).

  Next, the system control unit 19 moves the optical axis position in the disk radial direction of the objective lens 13 of the optical pickup 14 to the position indicated by the reading start position R0 stored in the memory 28 (step S4). In this control, the stepping motor 15 is driven to temporarily return the optical pickup 14 in the inner circumferential direction, and the innermost origin position (a position detected by a limit switch or a position mechanically locked by a stopper) is set. If detected, the stepping motor 15 is driven by the number of steps from which the objective lens 13 reaches the reading start position R0.

  When the spindle motor 11 is stably CAV-controlled at a predetermined number of revolutions and the optical axis position in the disk radial direction of the objective lens 13 of the optical pickup 14 reaches the read start position R0, the system control unit 19 The pulse signal FG ′ output from the N frequency divider 29 is monitored, and the process waits until the rising edge of the pulse signal FG ′ is detected (step S5; NO). In this embodiment, the circumferential position where the rising edge of the pulse signal FG ′ is detected is defined as θ = 0. During image reading, the system control unit 19 counts a clock generated by dividing the same crystal oscillation clock used for CAV control of the spindle motor 11, and the circumferential position with respect to the position of θ = 0. Is detected for each Δθ (deviation angle difference between pixels (dots) drawn adjacent to each other in the circumferential direction). Δθ is a declination difference between pixels drawn adjacent in the circumferential direction. The value of the deviation angle difference Δθ is obtained by calculation of Δθ = 2π / (number of dots per round) based on the number of dots per round of the disk.

  When the rising edge of the pulse signal FG ′ is detected (step S5; YES), the system control unit 19 starts the vibration of the tracking actuator by generating a vibration signal from the vibration signal generator 30 (step S6). The vibration signal generated by the vibration signal generator 30 is supplied to the tracking actuator of the optical pickup 14. The tracking actuator vibrates the objective lens 13 at a constant period in the disk radial direction according to the supplied vibration signal. By setting the vibration frequency Hz to a value larger than the spindle rotation speed rps, vibration is performed for one cycle or more per one rotation of the spindle. This vibration is continued until drawing is completed. The tracking servo is turned off during image reading.

  When the objective lens 13 is vibrated by the vibration signal, the system control unit 19 sets the “vibration frequency Hz” so that the value of “vibration frequency Hz / spindle rotation speed rps” becomes a circulation fraction with a long circulation digit number. It is desirable to set a value of “spindle speed rps”. That is, with such a setting, even if the number of times of overwriting is large, it is possible to prevent the irradiation positions of the laser beams from overlapping each other during overwriting. For example, if the vibration frequency is set to 200 Hz with respect to the spindle rotation speed 131.25 rps, the value of “vibration frequency / spindle rotation speed rps” is a circulation fraction with a long circulation digit number.

  The system control unit 19 initializes a memory access pointer indicating an address for writing data in the pixel column data storage area of the buffer memory 24 (step S7). In this embodiment, the system control unit 19 initializes the memory access pointer to an address for storing data at the position of the circumferential position θ = 0. Next, the system control unit 19 starts measuring the time required for one rotation (step S8). The system control unit 19 determines the level of the pulse signal MIR output from the comparator 27 (step S9). If the pulse signal MIR is at “H” level (step S9; “HIGH”), it is determined whether or not the value of data stored at the address indicated by the memory access pointer is “0” (step S10). If it is “0” (step S10; “0”), the system control unit 19 writes “1” in the memory (step S11). On the other hand, in other cases (step S10; "1"), since it is not necessary to update the value, the system control unit 19 proceeds to the process of step S12 without performing the writing process to the memory. On the other hand, when the level of the MIR signal is “L” level in step S9 (step S9; “LOW”), the system control unit 19 does not perform the writing process to the memory and proceeds to the process of step S12. .

  Next, the system control unit 19 increments the memory access pointer (step S12), and determines whether the measurement time has reached the time required for one rotation of the disk (step S13). When it is determined that it has not been reached (step S13; NO), the system control unit 19 returns to the process of step S9 and performs the gradation degree determination process for the next dot area. On the other hand, if it is determined in step S13 that it has reached (step S13; YES), the system control unit 19 determines whether the rotation of the spindle has reached a predetermined number of times (number of overwriting Nr) (step S14). ). If it is determined that the predetermined number of times has not been reached (step S14; NO), the system control unit 19 returns to the process of step S7 and continues the image reading process.

  As described above, in this embodiment, the system control unit 19 determines the binary gradation (white or black) according to the output signal from the comparator 27. Thereby, data indicating the gradation (white or black) for each pixel (dot) of the image drawn on the optical disc 100 is stored in the pixel row data storage area of the buffer memory 24.

  FIG. 6 is a diagram illustrating an example of the contents of data stored in the buffer memory 24. In the figure, (a) shows an image drawn on the optical disc 100, while (b) shows an example of the contents of data stored in the buffer memory 24. As shown in the figure, even when there is a difference in light and shade on the actual board surface, the system control unit 19 displays white (“1”) when the reflectance is equal to or higher than a predetermined reflectance, and black (“0”) otherwise. It is determined that the data is processed as monochrome data.

  At this time, as shown in step S14, the system control unit 19 performs overreading of the spindle while maintaining the irradiation position of the laser beam (that is, the radial position of the optical pickup 14) within a certain amplitude range. Rotate Nr by the number of times. When the number of rotations is completed, the laser beam irradiation position is moved in the outer peripheral direction by a predetermined distance Δr, and the laser beam irradiation position is kept within the above amplitude range, and the spindle is repeated Nr times the number of repeated readings. Repeat the process of rotating only. As described above, in this embodiment, the detection of the return light is continued during the period in which the spindle motor rotates for a predetermined number of times (in this embodiment, the number Nr of over-reading) at the disk radial position where the image is detected. The logical sum of the pulse signal MIR is obtained. Further, at this time, the tracking actuator is vibrated in the radial direction of the disk, so that the detection light can be detected with higher accuracy while minimizing the overlap of the locus of detection light.

  If it is determined in step S14 that the rotation of the spindle has reached the predetermined number of times Nr (step S14; YES), the system control unit 19 determines whether the image reading outer radius has been reached (step S15). If it is determined that it has not been reached (step S15; NO), the system control unit 19 returns to the process of step S4. On the other hand, when it is determined in step S15 that the image reading outer radius has been reached (step S15; YES), the system control unit 19 ends the vibration of the tracking actuator (step S16).

  That is, the system control unit 19 moves the distance Δr every time θ reaches 2π × Nr. When θ = 2π × Nr is reached, the system control unit 19 drives the stepping motor 15 by one microstep to move the optical axis position of the optical pickup 14 by the distance Δr in the disk outer circumferential direction. Δr is the unit feed width of the optical pickup 14 in the disk radial direction, that is, the amount of movement of the optical pickup 14 by one microstep of the stepping motor 15. The value of Δr is a value based on a command from the host device 200. As described above, the system control unit 19 gradually changes the diameter and performs measurement, and when the disk radial direction position reaches the reading end position R1, the image reading process ends.

  By repeatedly executing the processing from step S4 to step S15, pixel string data indicating an image drawn on the label surface of the optical disc 100 is stored in the buffer memory 24. When the processing up to step S16 is completed, the system control unit 19 transfers the data stored in the buffer memory 24 to the host device 200. In this way, the image drawn on the optical disc 100 is read, and pixel column data for each circumference representing the read image is transmitted to the host device 200. When the reception of all the pixel column data is completed, the host device 200 reproduces the drawing surface on the display device 300 using the acquired pixel column.

  Here, the operation of controlling the tracking actuator so that the irradiation position of the laser beam vibrates will be described below with reference to the drawings while comparing with the case of performing image reading without vibrating. FIG. 7 is a diagram illustrating an example of an image drawn on the optical disc 100. In FIG. 7, for the convenience of explanation, the circumference of the optical disc 100 is shown in a straight line. The example shown in FIG. 7 is an image drawn by the optical disc recording apparatus 1 according to this embodiment, and the drawing line (laser beam irradiation locus) is meanderingly drawn as shown.

  FIG. 8A is a diagram illustrating a locus of laser light at the time of image reading when image reading is performed without vibrating the irradiation position. The chain line in the figure indicates the locus of the laser beam during image reading. In FIG. 8B, in order to facilitate understanding, in the example shown in FIG. 8A, this portion is extracted by paying attention to only the (i + 5) row, and the number of columns in one round of the disk is J. It is shown. FIG. 9 shows the waveform of each part when the laser light passes through the drawn image (shown by a solid line in the drawing) shown in FIG. In the figure, the pulse signal MIR represents an image on the disk to some extent, but there are cases where it is desired to reproduce the original image with higher accuracy. In such a case, the method of this embodiment is effective.

  FIG. 10 is a diagram showing an example of the locus of the scanning position of the laser beam at one radial position when the number of overwriting Nr is set to “4” in this embodiment. In FIG. 10, for the convenience of explanation, the circumference of the optical disc 100 is shown in a straight line. According to FIG. 10, the laser beam scans a range in the disk radial direction wider than the movement amount Δr of the optical pickup 14 by one micro step by the vibration operation. In addition, since the laser beam frequency Hz / spindle rotation rps is set to be a decimal fraction, the laser beam trajectories do not overlap each other. Therefore, even if each reading area by the laser beam is narrow, more accurate image reading is realized. As is apparent from a comparison between FIG. 9 and FIG. 10, the optical disc reading apparatus 1 according to this embodiment can read an image with higher accuracy than the example shown in FIG. In the example shown in FIG. 10, the trajectories for four spindles are shown in a superimposed manner, but FIG. 11 is shown separately for each spindle revolution. As shown in FIG. 11, if the rotation speed of the spindle and the vibration frequency of the tracking actuator are determined so that the traces of the laser beams on each circumference do not overlap, the image can be detected with higher accuracy.

  Thus, in this embodiment, since the tracking actuator is controlled so that the irradiation position of the laser beam vibrates in the radial direction of the optical disk, an image can be reproduced with higher accuracy. For example, when there is a tracking shift during image drawing, when the image reading is performed without vibrating the laser beam, the locus of the laser beam at the time of drawing intersects the locus of the laser beam at the time of image reading. In some cases, the image cannot be read. On the other hand, in this embodiment, since the irradiation position of the laser beam is vibrated, even if tracking deviation occurs in a certain range, at least one of the laser beam irradiation trajectories vibrates in that range. It is possible to cross the drawing line at the part, and thereby it is possible to perform image reading with higher accuracy than in the past.

(3) Modifications Although the embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and can be implemented in various other forms. An example is shown below. In addition, you may combine each following aspect suitably.
The drawing layer 106 of the optical disc 100 only needs to change color according to at least one of heat and light. Further, the position of the drawing layer on the optical disc 100 is not limited to that shown in FIG. Good. Further, although the optical disc 100 is provided by each manufacturer, it is considered that the characteristics of the data recording layer and the drawing layer are different for each manufacturer. For example, when the heat absorption rate of the data recording layer is different, it is assumed that the level of laser light to be irradiated for forming pits and the level of laser light to be irradiated for discoloration are different. The same applies to the drawing layer. For this reason, data recording and drawing are actually performed on the optical discs 100 of a number of manufacturers in advance to determine how much laser light is suitable for irradiation, and such values are stored in the memory 28. You may make it leave. In this case, if it is stored in association with identification information (disc ID information) indicating the type of the optical disc 100, the disc ID information of the set optical disc 100 is read, and then laser light irradiation according to the disc type is performed. can do.
In the above-described embodiment, a non-rewritable optical disk such as a CD-R is used. However, a rewritable optical disk such as a CD-RW, DVD-RW, or CD / DVD-RW may be used.

  In the embodiment, the circumferential position at which image reading is started is set to θ = 0. Instead, a specific recognition code is formed on the inner peripheral side of the image reading area of the optical disc 100, and light is emitted prior to image reading. It is also possible to detect the circumferential position of this recognition code with the pickup 14, determine that position as θ = 0, and start image reading from this circumferential position. In this way, even if the optical disc 100 is inserted into or removed from the optical disc recording apparatus 1, the position of θ = 0 does not change, so that it is possible to continue image reading.

  In the embodiment described above, the optical disc 100 is rotated at a constant angular velocity, but may be rotated at a constant linear velocity. When rotating at a constant angular velocity, the length of pixel row data per rotation is uniquely determined by the number of samplings regardless of the radial position. On the other hand, when rotating at a constant linear velocity, the length of pixel column data per rotation becomes longer as the radial position is closer to the outer periphery.

  In the above-described embodiment, the gradation data on the circumference of the optical disc 100 is sampled and binarized, and the image is read with two gradations. However, the gradation is not limited to 2, but 3 It may be the above. In this case, for example, the optical disc may be rotated a plurality of times while changing the threshold value used for determination for each rotation, and the gradation degree may be determined according to the determination result with the plurality of threshold values. Further, for example, a plurality of comparators having different threshold values may be used, and the gradation may be determined according to the output values of the plurality of comparators.

  Note that the greater the number of samplings per revolution, the higher the resolution and the higher the image reproducibility. Further, the finer the feed width in the radial direction, the higher the resolution. However, in order to increase the number of samplings, it is necessary to reduce the rotation speed, and the finer the feed width, the longer the time required for reading. Therefore, it is preferable to select an appropriate rotation speed and feed width in accordance with the purpose and the like.

  In the above-described embodiment, the case where the visible image drawn on the optical disc 100 is read has been described. However, the image read by the optical disc recording apparatus 1 is not limited to the visible image, and for example, an invisible image written by infrared rays can also be read. . Also in this case, the optical disc 100 may be irradiated with laser light, and the gradation (for example, white or black) of each dot area on the optical disc 100 may be determined according to the amount of reflected light.

  In the embodiment described above, the radial read start position R0 and the read end position R1 of the optical disc 100 are stored in the memory 28 of the optical disc recording apparatus 1, and the system control unit 19 reads the read start position R0 and the read start position R0 from the memory 28. The end position R1 is read out. Instead of this, the host device 200 may instruct the optical disc recording device 1 of the reading start position R0 and the reading end position R1 in the radial direction of the optical disc 100. In this case, the optical disc recording apparatus 1 may read the image on the optical disc 100 within the designated range.

  In the above-described embodiment, the host device 200 instructs the optical disc recording device 1 about the unit movement amount Δr of the optical pickup 14, and the system control unit 19 moves the optical pickup 14 by the distance Δr in the disc outer peripheral direction. Instead of this, the unit movement amount Δr of the optical pickup 14 may be stored in the memory 28 of the optical disc recording apparatus 1 in advance. In the above-described embodiment, the host device 200 instructs the optical disk recording apparatus 1 to specify the number of dots S per rotation of the optical disc 100. Instead, the number of dots per rotation is stored in the memory 28. It may be stored in advance.

  In the embodiment described above, one byte is assigned to one sample (one dot), but one bit may be assigned to one sample (one dot). In this case, the number of samplings per round is preferably a multiple of 8.

  In the above-described embodiment, a configuration in which an AC signal generated such that the irradiation position of the laser beam vibrates in the radial direction, for example, a triangular wave signal, is adopted as the vibration signal at the time of image reading. If it vibrates in the direction and intersects with the groove 102 of the rotating optical disc 100, the vibration signal is sufficient. Therefore, various AC signals such as a sine wave signal can be given as the vibration signal in addition to the triangular wave signal. As described above, the vibration signal generator 30 may generate a vibration signal having a constant amplitude and a constant frequency so that the phase thereof is different for each turn when the optical disc 100 overlaps a plurality of turns.

It is sectional drawing of the optical disk which concerns on embodiment of this invention. It is a figure which shows the structure of the whole system which concerns on this embodiment. It is a time chart of various signals at the time of image reading. It is a figure for demonstrating the dot of the image which should be formed in an optical disk. It is a flowchart which shows the process performed by a system control part. It is a figure which shows an example of the content of the data memorize | stored in a buffer memory. It is a figure which shows an example of the image drawn on the optical disk. It is a figure for demonstrating the content of the process at the time of reading an image, without vibrating an irradiation position. It is a figure for demonstrating the content of the process at the time of reading an image, without vibrating an irradiation position. It is a figure for demonstrating the image reading process of this embodiment. It is a figure for demonstrating the image reading process of this embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Optical disk recording device, 10 ... Interface, 11 ... Spindle motor, 12 ... Spindle servo, 13 ... Objective lens, 14 ... Optical pick-up, 15 ... Stepping motor, 16 ... Feed mechanism, 17 ... Motor driver, 18 ... Focus servo, DESCRIPTION OF SYMBOLS 19 ... System control part, 20 ... Tracking servo, 21 ... ALPC circuit, 22 ... Laser driver, 23 ... Encoder, 24 ... Buffer memory, 25 ... Decoder, 26 ... LPF, 27 ... Comparator, 28 ... Memory, 29 ... N minutes Circumference device 30 ... vibration signal generator 100 ... optical disk 101 ... polycarbonate layer 102 ... groove 103 ... data recording layer 104 ... translucent layer 105 ... intermediate layer 106 ... drawing layer 107 ... semi-transparent layer 108 ... polycarbonate layer, 200 ... host device, 201 ... Control unit, 202 ... storage unit, 203 ... communication unit, 300 ... display device.

Claims (5)

A rotating means for rotating the optical disc;
A light irradiating means for irradiating the optical disk which is movable in the radial direction of the optical disk and rotated by the rotating means; and
An irradiation position operating means for operating an irradiation position of a laser beam irradiated from the light irradiation means toward the optical disc;
A feed unit that moves the light irradiation unit in a substantially radial direction of the disk by an amount corresponding to the pitch in the radial direction of the dot array each time the optical disk is rotated a plurality of times by the rotating unit.
An irradiation position control means for controlling the irradiation position operating means so as to vibrate the irradiation position of the laser light in the radial direction of the optical disc so that the irradiation locus of the laser light on the optical disc differs for each turn;
A gradation degree specifying means for receiving reflected light of the laser light applied to the optical disc by the light irradiating means for each predetermined dot area, and specifying a gradation degree for each dot area according to the received reflected light; ,
An image reading apparatus comprising: output means for outputting data indicating the gradation for each of the dot areas specified by the gradation specifying means. The irradiation position operating means operates the irradiation position of the laser light according to the voltage of the vibration signal,
The said irradiation position control means produces | generates the vibration signal which has a fixed amplitude and a fixed frequency so that the phase may differ for every turn, when an optical disk piles up around a round of multiple times. Image reading apparatus. A feed width information acquiring means for acquiring feed width information indicating a feed width;
The feed means acquires the feed width information from the radial reading start position to the reading end position indicated by the position information acquired by the position information acquisition means, each time the optical disk rotates a plurality of times. The image reading apparatus according to claim 1 , wherein the image reading device is moved in the radial direction by a feed width indicated by the feed width information acquired by the means. Comprising dot area information storage means for storing dot area information indicating the dot area;
The gradation level specifying means receives the reflected light of the laser beam irradiated onto the optical disc by the irradiation position control means for each dot area indicated by the dot area information stored in the dot area storage means, and receives the received reflected light. the image reading apparatus according to any one of claims 1 to 3, wherein the identifying the gradient for each said dot region in accordance with. Comprising dot area information acquisition means for acquiring dot area information indicating the dot area;
The gradation level specifying means receives the reflected light of the laser beam irradiated onto the optical disc by the irradiation position control means for each dot area indicated by the dot area information acquired by the dot area information acquisition means, and receives the received reflected light the image reading apparatus according to any one of claims 1 to 3, wherein identifying a gradient for each said dot region in accordance with.

Images