JP4055814B2 - Optical disc recording apparatus and control method - Google Patents

Description

  The present invention relates to an optical disk recording apparatus capable of forming a visible image on the surface of an optical disk.

  Conventionally, recordable optical disks such as CD-R (Compact Disc-Recordable) and CD-RW (Compact Disc-Rewritable) have been sold. When recording various data such as music data on these optical disks, an optical disk recording apparatus such as a CD-R drive apparatus or a CD-RW drive apparatus is used. In these optical disc recording apparatuses, information recording is performed by irradiating a recording surface formed on one surface of the optical disc with laser light corresponding to information to be recorded.

  By the way, in the optical disc as described above, visible information such as the title of the music data recorded on the recording surface and the title for identifying the recorded data is provided on the surface opposite to the recording surface on which the music data is recorded. The label which printed is attached. Such an optical disk is manufactured by printing a title or the like on a circular label sheet by a printer device or the like, and sticking the label sheet on a surface opposite to the recording surface of the optical disk.

  However, in order to produce an optical disc in which desired visible information such as a title is recorded on the heat sensitive surface as described above, a printer device is required. Therefore, after recording on the recording surface of a certain optical disk using the optical disk recording apparatus, the optical disk is taken out from the optical disk recording apparatus, and a label sheet printed by the printer apparatus as described above is pasted. You have to do complicated work.

  The present invention has been made in consideration of the above-described circumstances, and records visible information on the heat-sensitive surface of an optical disc in addition to recording information on the recording surface without separately preparing a new device or the like. It is an object of the present invention to provide an optical disc recording apparatus and an image forming method that can be used.

  In order to solve the above problems, an optical disk recording apparatus according to the present invention is an optical disk recording apparatus that records information by irradiating a recording surface of an optical disk with laser light, and is a light that irradiates an optical disk with laser light. A pickup, an irradiation position adjusting means for adjusting an irradiation position of the laser beam to the optical disk by the optical pickup, and an optical disk in which the recording surface is formed on one surface and the heat sensitive surface is formed on the other surface, An image formation control means for controlling the optical pickup and the irradiation position adjusting means so that a visible image corresponding to image information is formed on the heat-sensitive surface of the optical disc when set so as to face the optical pickup; When the visible image is formed, a beam spot diameter of a laser beam irradiated by the optical pickup to the heat-sensitive surface is Is characterized in the that the optical pickup to the recording surface; and a beam spot control means for controlling the optical pickup to be larger than the beam spot diameter of the laser light provided to the recording information.

  According to this configuration, by irradiating the heat-sensitive surface of the optical disc with laser light according to the image data, the heat-sensitive surface can be discolored to form a visible image corresponding to the image data. When such a visible image is formed, the laser beam is irradiated to a larger area while the optical disc is rotated once by increasing the beam spot diameter of the laser beam applied to the heat-sensitive surface of the optical disc. The time required for forming a visible image can be shortened.

  An optical disk recording apparatus according to another aspect of the present invention is an optical disk recording apparatus that records information by irradiating a recording surface of an optical disk with a laser beam, and an optical pickup that irradiates the optical disk with a laser beam; An irradiation position adjusting means for adjusting an irradiation position of the laser beam on the optical disk by the optical pickup, an optical disk in which the recording surface is formed on one surface and a heat sensitive surface is formed on the other surface, and the heat sensitive surface is the optical pickup. Means for controlling the optical pickup and the irradiation position adjusting means so that a visible image corresponding to image information is formed on the heat-sensitive surface of the optical disc when set so as to oppose each other, the optical pickup comprising: The intensity of the laser beam applied to the heat sensitive surface is such that the heat sensitive surface hardly changes based on the image information. Information relating to image formation control means for controlling the intensity or the second intensity at which the heat-sensitive surface changes to be greater than the first intensity, and information relating to the laser beam irradiated to the optical disc by the optical pickup And a servo unit that controls the optical pickup so that a desired laser beam is irradiated based on the detection result, and the image formation control unit is configured to control the light according to the control based on the image information. The intensity of the laser light emitted from the optical pickup when the intensity of the laser light emitted by the pickup continuously reaches the second intensity exceeds a certain time regardless of the content of the image information. Is controlled to become the first intensity for a predetermined time, and the servo means detects the result of the information relating to the laser beam irradiated with the first intensity. It is characterized by controlling the optical pickup based on.

  According to this configuration, by irradiating the heat-sensitive surface of the optical disc with laser light according to the image data, the heat-sensitive surface can be discolored to form a visible image corresponding to the image data. When such a visible image is formed, laser light control is performed regardless of the image data even when the intensity of the laser light corresponding to the image data lasts for a long time, which is the second intensity for changing the heat-sensitive surface. For this reason, the laser beam having the first intensity that hardly changes the heat-sensitive surface is irradiated, so that the laser beam control based on the irradiation result can be performed.

  An optical disk recording apparatus according to another aspect of the present invention is an optical disk recording apparatus that records information by irradiating a recording surface of an optical disk with a laser beam, and an optical pickup that irradiates the optical disk with a laser beam; An irradiation position adjusting means for adjusting an irradiation position of the laser beam on the optical disk by the optical pickup; and the optical pickup and the irradiation position adjusting means so that a visible image corresponding to image information is formed on the recording surface of the optical disk. Means for controlling, wherein the intensity of the laser light applied to the recording surface by the optical pickup is a first intensity at which the recording surface hardly changes based on the image information, or the first intensity. Image forming control means for controlling the recording surface to have one of the second intensities that vary greatly, and the optical disc. Servo information for detecting information related to the laser light emitted by the optical pickup and controlling the optical pickup so that a desired laser light is emitted based on the detection result. The control means changes the content of the image information when the intensity of the laser light emitted by the optical pickup continuously reaches the second intensity in accordance with the control based on the image information exceeds a certain time. Regardless, the intensity of the laser light emitted from the optical pickup is controlled to be the first intensity for a predetermined time, and the servo means detects the information regarding the laser light emitted at the first intensity. The optical pickup is controlled based on the above.

  According to this configuration, by irradiating the recording surface of the optical disc with laser light in accordance with the image data, the recording surface can be discolored to form a visible image corresponding to the image data. When such a visible image is formed, laser light control is performed regardless of the image data even when the laser light intensity corresponding to the image data is a second intensity that changes the recording surface for a long time. For this reason, the laser beam having the first intensity that hardly changes the recording surface is irradiated, so that the laser beam control based on the irradiation result can be performed.

  An optical disk recording apparatus according to another aspect of the present invention is an optical disk recording apparatus that records information by irradiating a recording surface of an optical disk with a laser beam, and an optical pickup that irradiates the optical disk with a laser beam; An irradiation position adjusting means for adjusting an irradiation position of the laser beam on the optical disk by the optical pickup, an optical disk in which the recording surface is formed on one surface and a heat sensitive surface is formed on the other surface, and the heat sensitive surface is the optical pickup. An image forming control means for controlling the optical pickup and the irradiation position adjusting means so that a visible image corresponding to image information is formed on the heat-sensitive surface of the optical disk when set so as to face each other; When set in the optical disc recording apparatus, the surface of the optical disc facing the optical pickup is the front side. Relative position adjusting means for adjusting a relative positional relationship between the optical pickup and a surface of the optical disc facing the optical pickup based on whether it is a heat sensitive surface or the recording surface. .

  According to this configuration, by irradiating the heat-sensitive surface of the optical disc with laser light according to the image data, the heat-sensitive surface can be discolored to form a visible image corresponding to the image data. When the optical disc is set, the positional relationship between the optical pickup and the surface facing the optical pickup can be adjusted depending on whether the thermal surface or the recording surface is set to face the optical pickup. it can. Therefore, even when the recording surface is set to face the optical pickup and the heat sensitive surface is set to face the optical pickup, the distance between the optical pickup and the surface facing this differs. The problem that various controls such as focus control cannot be performed due to the difference in distance can be suppressed.

  An optical disk recording apparatus according to another aspect of the present invention is an optical disk recording apparatus that records information by irradiating a recording surface of an optical disk with a laser beam, and an optical pickup that irradiates the optical disk with a laser beam; An irradiation position adjusting means for adjusting an irradiation position of the laser beam on the optical disk by the optical pickup; and an optical disk in which the recording surface is formed on one surface and a heat-sensitive surface is formed on the other surface, and a guide groove is formed on the recording surface. Is set in the guide groove based on the reflected light from the optical disk of the laser beam irradiated by the optical pickup when the optical disk formed in a spiral shape is set so that the thermal surface faces the optical pickup. Servo means for controlling the irradiation position adjusting means so that laser light is irradiated along the guide groove, and along the guide groove by the servo means. Image forming control means for controlling the laser light emitted from the optical pickup so that a visible image corresponding to image information is formed on the heat-sensitive surface of the optical disc while the irradiation position of the laser light is moved It is characterized by comprising.

  According to this configuration, by irradiating the heat-sensitive surface of the optical disc with laser light according to the image data, the heat-sensitive surface can be discolored to form a visible image corresponding to the image data. At this time, the irradiation of the laser beam is more complicated than when recording is performed on the recording surface by detecting the guide groove formed on the recording surface and moving the laser beam irradiation position along the detected guide groove. Visible image formation can be performed without performing position control.

According to another aspect of the present invention, there is provided an optical disk recording apparatus, comprising: an optical disk recording apparatus that forms a visible image on the optical disk by irradiating the optical disk with laser light; a disk rotating unit that rotates the optical disk; Rotation detecting means for detecting, an optical pickup for irradiating the optical disk rotated by the disk rotating means with laser light, and moving the optical pickup by a predetermined first distance in the disk radial direction an optical pickup moving means, disposed within the light pickup, a laser beam the optical pickup is irradiated, the irradiation position; and a tracking control means for controlling so as to move in the disk radial direction, the tracking control means irradiates a laser beam to the optical disc information recording Making, while performing the tracking servo control based on laser beam irradiation of the optical pickup, in forming a visible image by irradiating a laser beam to the optical disc, the radial position of the optical pickup In the fixed state, the irradiation position of the laser beam emitted from the optical pickup is changed in the radial direction by a second distance smaller than the first distance every time the rotation detecting unit detects one rotation. The optical pickup moving means moves the optical pickup in the radial direction by the first distance when the rotation detecting means detects that the optical disk has been rotated by a predetermined number of rotations. Yes.
In addition, a control method according to the present invention includes a disk rotating unit that rotates an optical disk, and an optical pickup that irradiates the optical disk with laser light, and a visible image is applied to the optical disk by irradiating the optical disk with laser light. A method of controlling an optical disk recording apparatus to be formed, the first step of detecting the rotation state of the optical disk rotated by the disk rotating means, and information recording by irradiating the optical disk with laser light Performs tracking servo control based on the laser beam irradiated by the optical pickup, while the optical pickup is fixed in the radial position when the optical disk is irradiated with the laser beam to form a visible image. The position of the laser beam irradiated from the optical pickup in the Every time it detects that it has made one rotation, it detects that the optical disk has been rotated a predetermined number of times, and a second step of moving the optical disk in a radial direction by a second distance smaller than a predetermined first distance. And a third step of moving the optical pickup in the radial direction by the first distance.
An optical disk recording apparatus according to another aspect of the present invention is an optical disk recording apparatus that records information by irradiating a recording surface of an optical disk with a laser beam, and an optical pickup that irradiates the optical disk with a laser beam; Rotation drive means for rotating the optical disk, clock signal output means for outputting a clock signal having a frequency corresponding to the rotation speed of the optical disk by the rotation drive means, and the recording surface on one surface and a heat sensitive surface on the other surface The optical pickup is controlled so that a visible image corresponding to image information is formed on the thermal surface of the optical disc when the optical disc on which the optical disc is formed is set so that the thermal surface faces the optical pickup. Means from the optical pickup based on the image information for each cycle of the clock signal by the signal output means. Image formation control means for controlling the emitted laser light, rotation detection means for detecting that the optical disk has been rotated once from a predetermined reference position by the rotation driving means, and the visible image as the thermal sensitivity of the optical disk. When the rotation detecting means detects that the optical disk has been rotated once from the predetermined reference position in a state where the optical pickup is irradiated with the optical pickup to form a surface, the laser by the optical pickup And an irradiation position adjusting means for moving a light irradiation position by a predetermined amount in a predetermined radial direction of the optical disk set in the optical disk recording apparatus.

  According to this configuration, by irradiating the heat-sensitive surface of the optical disc with laser light according to the image data, the heat-sensitive surface can be discolored to form a visible image corresponding to the image data. When this visible image is formed, laser light irradiation control for visible image formation is performed every period of the clock signal having a frequency corresponding to the rotation speed of the optical disk, that is, every time the optical disk rotates by a certain angle. A visible image having contents (for example, density) corresponding to the image data can be formed at a position for each fixed angle.

  An optical disk recording apparatus according to another aspect of the present invention is an optical disk recording apparatus that records information by irradiating a recording surface of an optical disk with a laser beam, and an optical pickup that irradiates the optical disk with a laser beam; Rotation drive means for rotating the optical disk, rotation detection means for detecting that the optical disk has been rotated once from a predetermined reference position by the rotation drive means, and the recording surface on one surface is thermally sensitive to the other surface. The optical pickup is controlled so that a visible image corresponding to image information is formed on the thermal surface of the optical disc when the optical disc having the surface is set so that the thermal surface faces the optical pickup. Image forming control means, and a laser by the optical pickup for forming the visible image on the heat-sensitive surface of the optical disc. When the rotation detecting means detects that the optical disc has been rotated once from the predetermined reference position in a state where the optical pickup is irradiated, the irradiation position of the laser beam by the optical pickup is set in the optical disc recording apparatus. And an irradiation position adjusting means for moving the optical disk by a predetermined amount in a predetermined radial direction, wherein the image formation control means is the predetermined reference of the thermal surface of the optical disk rotated by the rotation driving means. In order to form the visible image from a position, the optical pickup is irradiated with laser light, while the irradiation position of the laser light reaches the predetermined reference position of the optical disc from a position ahead of the predetermined amount by the predetermined amount. The optical pick so that the laser beam for forming the visible image is not irradiated to the region up to the reference position of Tsu is characterized in that to control the flop.

  According to this configuration, by irradiating the heat-sensitive surface of the optical disc with laser light according to the image data, the heat-sensitive surface can be discolored to form a visible image corresponding to the image data. When such a visible image is formed, a visible image is formed by irradiating a laser beam from the reference position of the optical disc while rotating the optical disc, and the region immediately before the laser beam irradiation position returns to the reference position. The laser beam irradiation for forming a visible image is not performed. Therefore, the laser light irradiation position control is disturbed for some reason such as unstable rotation of the optical disk, the laser light is continuously irradiated from the reference position, the optical disk is rotated once, and the irradiation position passes through the reference position again. In other words, even if the laser beam irradiation position moves to a position that overlaps the position where the laser beam has already been irradiated later, the laser beam for forming a visible image is prevented from being irradiated to that position. As a result, the quality of the visible image formed can be prevented from deteriorating.

  An optical disk recording apparatus according to another aspect of the present invention is an optical disk recording apparatus that records information by irradiating a recording surface of an optical disk with a laser beam, and an optical pickup that irradiates the optical disk with a laser beam; One of irradiation position adjusting means for adjusting the irradiation position of the laser beam on the optical disk by the optical pickup, disk identification means for acquiring disk identification information for identifying the type of the optical disk set in the optical disk recording apparatus, When the optical disc having the recording surface on the surface and the heat sensitive surface on the other surface is set so that the heat sensitive surface faces the optical pickup, a visible image corresponding to image information is displayed on the heat sensitive surface of the optical disc. Means for controlling the optical pickup and the irradiation position adjusting means to be formed on a surface, It is characterized by comprising an image forming control unit for controlling the optical pickup and the irradiation position adjusting means according to the type of the optical disc identified by disk identification means.

  According to this configuration, by irradiating the heat-sensitive surface of the optical disc with laser light according to the image data, the heat-sensitive surface can be discolored to form a visible image corresponding to the image data. When such a visible image is formed, control for forming a visible image can be performed according to the type of the set disc.

  According to another aspect of the present invention, there is provided an optical disc recording apparatus according to an optical pickup that irradiates a laser beam to an optical disc, a modulation unit that modulates information supplied from the outside, and information supplied from the modulation unit. In an optical disk recording apparatus comprising a laser light control means for controlling laser light emitted from the optical pickup, with respect to the heat-sensitive surface of the optical disk in which the recording surface is formed on one surface and the heat-sensitive surface is formed on the other surface. In the case of forming a visible image, a prohibiting unit that prohibits modulation by the modulating unit with respect to image information supplied from the outside, and when the thermal surface of the optical disc is set to face the optical pickup, A visible image corresponding to unmodulated image information supplied from the modulation means is formed on the heat-sensitive surface of the optical disc. It is characterized by comprising an image forming control means for controlling the serial laser beam control means.

  According to this configuration, by irradiating the heat-sensitive surface of the optical disc with laser light according to the image data, the heat-sensitive surface can be discolored to form a visible image corresponding to the image data. When such a visible image is formed, the image data is not modulated because the modulation by the modulation means for modulating the record data is prohibited when information is recorded on the recording surface. Therefore, a data transfer configuration for recording information on a recording surface can be used in combination without providing a special data transfer configuration for forming a visible image corresponding to the image data.

  An optical disk recording apparatus according to another aspect of the present invention is an optical disk recording apparatus that records information by irradiating a recording surface of an optical disk with laser light, the optical pickup that irradiates the optical disk with laser light, and the light An irradiation position adjusting means for adjusting an irradiation position of the laser beam on the optical disk by the pickup, and an optical disk in which the recording surface is formed on one surface and a heat sensitive surface is formed on the other surface, the heat sensitive surface faces the optical pickup. And an image formation control means for controlling the optical pickup and the irradiation position adjustment means so that a visible image corresponding to image information is formed on the heat-sensitive surface of the optical disc when set as described above, The image formation control means emits laser light emitted from the optical pickup in accordance with the gradation level indicated in the image information. It is characterized in that Gosuru.

  According to this configuration, by irradiating the heat-sensitive surface of the optical disc with laser light according to the image data, the heat-sensitive surface can be discolored to form a visible image corresponding to the image data. When such a visible image is formed, laser light control can be performed according to the gradation of each position (coordinate) on the heat-sensitive surface indicated in the image data, and a visible image with gradation expression is formed. be able to.

  The image forming method according to the present invention uses an optical disc recording apparatus having an optical pickup for recording information by irradiating a laser beam onto the recording surface of the optical disc, and is formed on the surface opposite to the recording surface of the optical disc. A method for forming a visible image on a heat-sensitive surface, wherein image information is obtained by moving a laser beam irradiation position by the optical pickup to the heat-sensitive surface along a predetermined spiral or concentric circumferential path. The optical pickup irradiates the optical pickup so that a visible image corresponding to is formed on the heat-sensitive surface of the optical disc. In the laser light control, the optical disc is divided into a plurality of adjacent fan-shaped portions. An area including a predetermined number (multiple) of the routes to be processed is a unit area, and the unit area is expressed so that the density of the unit area in the visible image is expressed. It is characterized by controlling the irradiation timing of the laser light irradiated on each of the paths belonging to the area.

  According to this method, a visible image corresponding to the image data can be formed by irradiating the heat-sensitive surface of the optical disc with laser light according to the image data, thereby changing the color of the heat-sensitive surface. When such a visible image is formed, laser light irradiation timing control can be performed according to the gradation degree of each position (coordinate) on the heat sensitive surface indicated in the image data, and the visible image with gradation expression can be obtained. Can be formed.

  According to the present invention, visible information can be recorded on the heat-sensitive surface of the optical disc in addition to recording information on the recording surface without separately preparing a new device or the like.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
A. Configuration of Embodiment The present invention is an optical disc recording apparatus that records information by irradiating a recording surface of an optical disc with a laser beam. In addition to recording information on such a recording surface, a surface opposite to the recording surface In addition, a laser beam is irradiated on the heat-sensitive surface of the optical disk on which the heat-sensitive surface is formed, thereby forming a visible image corresponding to the image data. In the following, the configuration of an optical disc capable of forming a visible image as described above will be described first, and then the configuration of an optical disc recording apparatus capable of recording information and forming a visible image on the optical disc. explain.

A-1. Configuration of Optical Disc FIG. 1 is a side sectional view showing a configuration of a disc-shaped optical disc capable of recording information on one side and forming a visible image on the other side. As shown in FIG. 1, this optical disc D includes a protective layer 201, a recording layer (recording surface) 202, a reflective layer 203, a protective layer 204, a heat-sensitive layer (heat-sensitive surface) 205, and a protective layer 206. It has a structure in which these are stacked in the above order. The figure schematically shows the structure of the optical disc D, and the dimensional ratios of the layers are not as shown in this figure.

  A pregroove (guide groove) 202a is spirally formed on the surface of the recording layer 202. When information is recorded on the optical disc D, laser light is irradiated along the pregroove 202a. It will be. Therefore, when recording information, the surface on the protective layer 201 side (the upper side in the figure) of the optical disc D (hereinafter referred to as the recording surface) is set so as to face the optical pickup of the optical disc recording apparatus, and the optical pickup irradiates the optical disc. The information is recorded by moving the laser beam to be moved along the pregroove 202a. On the other hand, when a visible image is formed on the surface of the optical disc D, the optical disc D is placed so that the surface on the protective layer 206 side (hereinafter referred to as a heat sensitive surface) faces the optical pickup of the optical disc recording apparatus according to the present invention. set. Then, by irradiating the heat-sensitive layer 205 with laser light, a desired position of the heat-sensitive layer 205 is thermally changed to form a visible image. As described above, the optical disc D has substantially the same configuration as the CD-R used conventionally except that the thermal layer 205 is provided, and the detailed configuration of the recording layer 202 and the like is not described. To do. In the present specification, the “heat-sensitive surface” is a surface that changes color when irradiated with laser light, and is a surface formed by the heat-sensitive layer 205 having such properties.

A-2. Configuration of Optical Disc Recording Device Next, FIG. 2 is a block diagram showing the configuration of the optical disc recording device according to an embodiment of the present invention. As shown in the figure, an optical disk recording apparatus 100 is connected to a host personal computer (PC) 110, and includes an optical pickup 10, a spindle motor 11, an RF (Radio Frequency) amplifier 12, a servo circuit 13, and the like. The decoder 15, the control unit 16, the encoder 17, the strategy circuit 18, the laser driver 19, the laser power control circuit 20, the frequency generator 21, the stepping motor 30, the motor driver 31, and the motor controller 32. A PLL (Phase Locked Loop) circuit 33, a FIFO (First In First Out) memory 34, a drive pulse generator 35, and a buffer memory 36.

  The spindle motor 11 is a motor that rotationally drives an optical disk D that is a target for recording data, and the number of rotations is controlled by a servo circuit 13. In the optical disk recording apparatus 100 according to the present embodiment, recording or the like is performed by a CAV (Constant Angular Velocity) method, and therefore the spindle motor 11 rotates at a constant angular velocity set by an instruction from the control unit 16 or the like. It is supposed to do.

  The optical pickup 10 is a unit that irradiates the optical disk D rotated by the spindle motor 11 with a laser beam, and its configuration is shown in FIG. As shown in the figure, the optical pickup 10 includes a laser diode 53 that emits a laser beam B, a diffraction grating 58, an optical system 55 that focuses the laser beam B on the surface of the optical disc D, and a light receiving device that receives reflected light. An element 56 is provided.

  In the optical pickup 10, the laser diode 53 emits a laser beam B having an intensity corresponding to the drive current when supplied with a drive current from the laser driver 19 (see FIG. 2). The optical pickup 10 separates the laser beam B emitted from the laser diode 53 into a main beam, a preceding beam, and a succeeding beam by a diffraction grating 58, and these three laser beams are polarized beam splitter 59, collimator lens 60, 1 / The light is condensed on the surface of the optical disc D through the four-wavelength plate 61 and the objective lens 62. Then, the three laser beams reflected on the surface of the optical disc D are transmitted again through the objective lens 62, the quarter wavelength plate 61, and the collimator lens 60, reflected by the polarization beam splitter 59, and passed through the cylindrical lens 63. The light is incident on the light receiving element 56. The light receiving element 56 outputs a received signal to the RF amplifier 12 (see FIG. 2), and the received light signal is supplied to the control unit 16 and the servo circuit 13 via the RF amplifier 12.

  The objective lens 62 is held by a focus actuator 64 and a tracking actuator 65 so as to be movable in the optical axis direction of the laser beam B and the radial direction of the optical disc D. Each of the focus actuator 64 and the tracking actuator 65 moves the objective lens 62 in the optical axis direction and the radial direction according to the focus error signal and the tracking error signal supplied from the servo circuit 13 (see FIG. 2). The servo circuit 13 generates a focus error signal and a tracking error signal based on the light reception signal supplied via the light receiving element 56 and the RF amplifier 12, and moves the objective lens 62 as described above to perform focus control. And tracking control.

  The optical pickup 10 has a front monitor diode (not shown). When the laser diode 53 emits laser light, a current is generated in the front monitor diode that receives the emitted light, and the current is 2 is supplied from the optical pickup 10 to the laser power control circuit 20 shown in FIG.

  The RF amplifier 12 amplifies the EFM (Eight to Fourteen Modulation) modulated RF signal supplied from the optical pickup 10, and outputs the amplified RF signal to the servo circuit 13 and the decoder 15. The decoder 15 performs EFM demodulation on the EFM-modulated RF signal supplied from the RF amplifier 12 during reproduction to generate reproduction data.

  The servo circuit 13 is supplied with an instruction signal from the control unit 16, an FG pulse signal having a frequency corresponding to the rotation speed of the spindle motor 11 supplied from the frequency generator 21, and an RF signal from the RF amplifier 12. The servo circuit 13 performs rotation control of the spindle motor 11 and focus control and tracking control of the optical pickup 10 based on these supplied signals. When recording information on the recording surface of the optical disc D (see FIG. 1) or when forming a visible image on the heat-sensitive surface of the optical disc D (see FIG. 1), the spindle motor 11 is driven at a constant angular velocity. In this embodiment, either a method of driving at a constant speed (CAV: Constant Angular Velocity) or a method of rotating the optical disc D so as to have a constant recording linear velocity (CLV: Constant Linear Velocity) may be used. The optical disk recording apparatus 100 according to the above employs the CAV method, and the servo circuit 13 rotates the spindle motor 11 at a constant angular velocity instructed by the control unit 16.

  The buffer memory 36 is information supplied from the host PC 110 to be recorded on the recording surface of the optical disc D (hereinafter referred to as recording data) and information corresponding to a visible image to be formed on the thermal surface of the optical disc D (hereinafter referred to as image data). ). The recording data stored in the buffer memory 36 is output to the encoder 17, and the image data is output to the control unit 16.

  The encoder 17 performs EFM modulation on the recording data supplied from the buffer memory 36 and outputs it to the strategy circuit 18. The strategy circuit 18 performs time axis correction processing or the like on the EFM signal supplied from the encoder 17 and outputs the result to the laser driver 19.

  The laser driver 19 drives a laser diode 53 (see FIG. 3) of the optical pickup 10 according to a signal modulated according to the recording data supplied from the strategy circuit 18 and the control of the laser power control circuit 20.

  The laser power control circuit 20 controls the laser power emitted from the laser diode 53 (see FIG. 3) of the optical pickup 10. Specifically, the laser power control circuit 20 controls the laser driver 19 so that a laser beam having a value that matches the target value of the optimum laser power indicated by the control unit 16 is emitted from the optical pickup 10. The laser power control by the laser power control circuit 20 performed here is controlled so that laser light having a target intensity is emitted from the optical pickup 10 using the current value supplied from the front monitor diode of the optical pickup 10. Feedback control.

  In the FIFO memory 34, the image data supplied from the host PC 110 and stored in the buffer memory 36 is supplied via the control unit 16 and sequentially stored. Here, the image data stored in the FIFO memory 34, that is, the image data supplied from the host PC 110 to the optical disc recording apparatus 100 includes the following information. This image data is data for forming a visible image on the surface of the disk-shaped optical disk D. As shown in FIG. 4, each of n pieces of data on a large number of concentric circles centering on the center O of the optical disk D is shown. Information indicating the degree of gradation (shading) is described for each coordinate (indicated by a black dot in the figure). The image data includes coordinate points P11, P12... P1n in which information indicating the gradation of these coordinates belongs to the innermost circle, coordinates P21, P22... P2n belonging to one of the outer circles, Further, the data indicating the gradation of each coordinate point up to the coordinate Pmn of the outermost circle in the order of the coordinates belonging to one outer circle is described, and the FIFO memory 34 has such polar coordinates. Information indicating the degree of gradation of each coordinate is supplied in the order as described above. FIG. 4 is a diagram schematically showing the positional relationship between the coordinates, and the actual coordinates are arranged more densely than those shown. When the host PC 110 creates image data to be formed on the photosensitive surface of the optical disc D in a commonly used bitmap format or the like, the bitmap data is converted into the polar coordinate format data as described above. Then, the converted image data may be transmitted from the host PC 110 to the optical disc recording apparatus 100.

  When a visible image is formed on the heat-sensitive surface of the optical disc D based on the image data supplied as described above, the FIFO memory 34 is supplied with a clock signal for image recording from the PLL circuit 33. It has become. Each time the clock pulse of the image recording clock signal is supplied, the FIFO memory 34 outputs information indicating the gradation degree of one coordinate accumulated first to the drive pulse generator 35. Yes.

  The drive pulse generator 35 generates a drive pulse for controlling the irradiation timing of the laser light emitted from the optical pickup 10. Here, the drive pulse generation unit 35 generates a drive pulse having a pulse width corresponding to information indicating the degree of gradation for each coordinate supplied from the FIFO memory 34. For example, when the degree of gradation at a certain coordinate is relatively large (when the density is large), a drive pulse with a light level (second intensity) pulse width increased is generated as shown in the upper part of FIG. For coordinates with a relatively small degree of furnishing, as shown in the lower part of FIG. 5, a drive pulse with a reduced write level pulse width is generated. Here, the light level is a power level at which the heat-sensitive surface (heat-sensitive layer 205) is clearly discolored when the laser power of that level is irradiated onto the heat-sensitive surface of the optical disc D. When the optical pickup 10 is supplied to the optical pickup 10, light level laser light is emitted from the optical pickup 10 for a time corresponding to the pulse width. Therefore, when the gradation is large, the light level laser beam is irradiated for a longer time, and a larger area in the unit area of the heat-sensitive surface of the optical disc D is discolored. It will be visually recognized as a dark area. In this embodiment, the gradation shown in the image data is expressed by varying the length of the area to be changed per unit area (unit length) in this way. The servo level (first intensity) is a power level at which the thermal surface hardly changes when the thermal surface of the optical disc D is irradiated with the laser power of that level, and for a region that does not need to be discolored. What is necessary is just to irradiate the laser beam of the said servo level, without irradiating the laser beam of a light level.

  The drive pulse generator 35 generates a drive pulse in accordance with the information indicating the gradation for each coordinate as described above, and performs laser power control by the laser power control circuit 20, focus control by the servo circuit 13, and When it is necessary to perform the tracking control, a light level pulse or a servo level pulse for a very short period is inserted regardless of the information indicating the gradation level. For example, as shown in the upper part of FIG. 6, in order to express a visible image according to the gradation of a certain coordinate in the image data, it is necessary to irradiate laser light having a light level for a period of time T1. When the time T1 is longer than a predetermined servo cycle ST for controlling the laser power, the servo off-pulse (SSP1) for a very short time t after the servo cycle ST elapses from the time when the write level pulse is generated. ) Is inserted. On the other hand, as shown in the lower part of FIG. 6, when it is necessary to irradiate a laser beam with a servo level for a period longer than the servo cycle ST in order to represent a visible image according to the gradation of a certain coordinate in the image data, A servo on pulse (SSP2) is inserted after the servo cycle ST has elapsed after the level pulse is generated.

  As described above, the laser power control by the laser power control circuit 20 is based on the current (intensity of the irradiated laser light) supplied from the front monitor diode that receives the laser light irradiated from the laser diode 53 (see FIG. 3) of the optical pickup 10. (The current having a value corresponding to the current value). More specifically, as shown in FIG. 7, the laser power control circuit 20 samples and holds a value corresponding to the intensity of the irradiation laser beam received by the front monitor diode 53a as described above (S201, S202). . Then, when irradiation is performed with the light level as a target value, that is, when a light level drive pulse (see FIGS. 5 and 6) is generated, the light is supplied from the control unit 16 based on the sample and hold result. Laser power control is performed so that the laser light of the light level target value is irradiated (S203). Further, when irradiation is performed with the servo level as a target value, that is, when a servo level drive pulse (see FIGS. 5 and 6) is generated, it is supplied from the control unit 16 based on the sample and hold result. Laser power control is performed so that laser light of the target servo level value is irradiated (S204). Therefore, when the write level or servo level pulse is not continuously output for a time longer than the predetermined servo cycle ST (sample cycle), the servo off pulse SSP1 and the servo on pulse are output as described above regardless of the contents of the image data. SSP2 is forcibly inserted so that the laser power can be controlled for each level as described above.

  As described above, the servo off pulse SSP1 is inserted not only for controlling the laser power but also for performing focus control and tracking control by the servo circuit 13. That is, the tracking control and the focus control are based on the RF signal received by the light receiving element 56 (see FIG. 3) of the optical pickup 10, that is, the return light (reflected light) from the optical disk D of the laser light emitted from the laser diode 53. Done. FIG. 8 shows an example of a signal received by the light receiving element 56 when the heat sensitive layer 205 (see FIG. 1) is irradiated with laser light. As shown in the figure, the reflected light when the light level laser beam is irradiated includes an element of a peak portion K1 when the laser beam rises and a shoulder portion K2 where the level becomes constant thereafter. It is considered that the portion shown is the energy used for discoloring the heat sensitive layer 205. The energy used for the color change of the thermosensitive layer 205 is not always a stable value, and may vary depending on various situations. Therefore, it is conceivable that the shape of the shaded portion in the figure changes each time, that is, the reflected light of the light level laser light is not always stable and can be obtained with a lot of noise and the like. There is a risk that accurate focus control and tracking control may be hindered. Therefore, as described above, when the light level laser beam is continuously irradiated for a long time, the reflected light of the servo level laser beam cannot be obtained, and accurate focus control and tracking control cannot be performed. End up.

Therefore, by inserting the servo off-pulse SSP1 as described above, the reflected light of the servo level laser light can be periodically acquired, and focus control and tracking control are executed based on the acquired reflected light. It is. When forming a visible image on the heat-sensitive surface of the optical disc D, unlike when recording on the recording surface, it is not necessary to trace along a pre-groove (guide groove) formed in advance. Therefore, in this embodiment, the target value of tracking control is a fixed value (a constant offset voltage is set).
Such a control method can be applied not only when image information is formed on the heat-sensitive surface but also when image information is formed on the recording surface. That is, if a material that changes not only the reflectance but also the color development when irradiated with laser light is used for the recording surface (recording layer 202), an image can be formed on the recording surface as well as the heat-sensitive surface. When a visible image is formed on the recording surface in this way, the original data recording cannot be performed on the portion where the visible image is formed. Therefore, the data recording area and the visible image forming area are separated in advance. Is preferred.

  As described above, it is preferable that the time for inserting the servo off-pulse SSP1 and the servo off-pulse SSP2 is a minimum time within a range that does not hinder the execution of various servos such as laser power control, tracking control, and focus control. By making the insertion time very short, various servos as described above can be performed with almost no influence on the formed visible image.

  Returning to FIG. 2, the PLL circuit (signal output means) 33 multiplies the FG pulse signal having a frequency corresponding to the rotation speed of the spindle motor 11 supplied from the frequency generator 21, and uses it for the visible image formation described later. Output clock signal. The frequency generator 21 outputs an FG pulse signal having a frequency corresponding to the number of spindle revolutions using a counter electromotive current obtained by the motor driver of the spindle motor 11. For example, as shown in the upper part of FIG. 9, when the frequency generator 21 generates eight FG pulses while the spindle motor 11 makes one revolution, that is, the optical disk D makes one revolution, the lower part of FIG. As shown in FIG. 2, the PLL circuit 33 outputs a clock signal (for example, a frequency of 5 times the FG pulse signal and 40 high-level pulses during one rotation of the optical disk D) obtained by multiplying the FG pulse, that is, the spindle motor 11. To output a clock signal having a frequency corresponding to the rotational speed of the optical disk D rotated. A clock signal obtained by multiplying the FG pulse signal in this way is output from the PLL circuit 33 to the FIFO memory 34, and the gradation of one coordinate is added to the clock signal every cycle, that is, every time the disk D rotates by a certain angle. The data shown is output from the FIFO memory 34 to the drive pulse generator 35. As described above, the PLL circuit 33 may be used to generate a clock signal obtained by multiplying the FG pulse. However, when the spindle motor 11 is a motor with sufficiently stable rotational drive capability. In this case, a crystal oscillator may be provided in place of the PLL circuit 33 to generate a clock signal obtained by multiplying the FG pulse as described above, that is, a clock signal having a frequency corresponding to the rotational speed of the optical disc D.

  The stepping motor 30 is a motor for moving the optical pickup 10 in the radial direction of the optical disc D set on the optical disc D. The motor driver 31 rotates the stepping motor 30 by an amount corresponding to the pulse signal supplied from the motor controller 32. The motor controller 32 generates a pulse signal according to the movement amount and the movement direction according to the movement start instruction including the movement direction and movement amount in the radial direction of the optical pickup 10 instructed from the control unit 16, and the motor driver 31. Output to. The stepping motor 30 moves the optical pickup 10 in the radial direction of the optical disc D, and the spindle motor 11 rotates the optical disc D with respect to the optical disc D, whereby the laser light irradiation position of the optical pickup 10 is set to various positions on the optical disc D. It can be moved, and these components constitute the irradiation position adjusting means.

The control unit 16 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like, and controls each unit of the optical disc recording apparatus 100 according to a program stored in the ROM. The recording process on the recording surface of the optical disc D and the image forming process on the heat-sensitive surface of the optical disc D are centrally controlled.
What has been described above is the configuration of the optical disc recording apparatus 100 according to the present embodiment.

B. Operation of the Embodiment Next, the operation of the optical disc recording apparatus 100 having the above configuration will be described. As described above, the optical disc recording apparatus 100 can record information such as music data supplied from the host PC 110 on the recording surface of the optical disc D, and the host PC 110 on the thermal surface of the optical disc D. A visible image corresponding to the image data supplied from can be formed. Hereinafter, the operation of the optical disc recording apparatus 100 capable of performing processing such as information recording and visible image formation will be described with reference to FIGS.

  First, when the optical disc D is set in the optical disc recording apparatus 100, the control unit 16 controls the optical pickup 10 and the like, and ATIP (Absolute Time In Pregroove) information is provided on the surface of the set optical disc D facing the optical pickup 10. Is detected (step Sa1). As is well known, the ATIP information is information recorded in advance in a pre-groove on the recording surface of the CD-R. When the ATIP information is recorded in this way, the recording surface of the optical disc D faces the optical pickup 10. You can see that it is set. On the other hand, when ATIP information is not recorded, it can be seen that the optical disc D is set so that the heat-sensitive surface of the optical disc D faces the optical pickup 10. That is, the control unit 16 detects which side of the optical disk D is set toward the optical pickup 10 by detecting the presence or absence of ATIP information as described above. In addition to the above-described method of detecting which surface is set toward the optical pickup 10 depending on the presence or absence of ATIP information, other methods, for example, when performing focus servo, Accordingly, it may be detected which surface is set toward the optical pickup 10 side. That is, the distance between the optical pickup and the opposing surface of the optical disc D facing the optical pickup varies greatly depending on which surface is set toward the optical pickup 10 side. From this control amount, it can be detected from which surface the optical disc D is set.

  Here, when the ATIP information is detected from the set optical disc D, it is determined that the optical disc D is set so that the recording surface faces the optical pickup 10, and the control unit 16 determines the recording surface with respect to the recording surface. Control for recording the recording data supplied from the host PC 110 is performed (step Sa2). Since the control for recording the recording data performed here is the same as that of the conventional optical disk recording apparatus (CD-R drive apparatus), the description thereof is omitted.

  On the other hand, when the ATIP information is not detected from the set optical disc D, it is determined that the optical disc D is set so that the thermal surface faces the optical pickup 10, and the control unit 16 determines the disc of the set optical disc D. It is determined whether or not an ID can be acquired (step Sa3). In the present embodiment, the disc ID of the optical disc D is a disc ID recorded on the thermal surface of the optical disc D (see FIG. 1) having a recording surface and a thermal surface. For example, as shown in FIG. A visible image corresponding to the encoded information is described along the circumference of the outermost peripheral portion of the optical disc D on the heat sensitive surface side. In the present embodiment, as shown in the figure, the disk ID is formed on the heat-sensitive surface of the optical disk D by forming a reflective area 301a and a non-reflective area 301b having a length corresponding to the code along the circumference of the outermost peripheral portion. It is described. The control unit 16 obtains the disk ID from the reflected light by tracing the irradiation position of the laser light of the optical pickup 10 along the outermost circumference of the optical disk D.

  Therefore, when the reflective area 301a and the non-reflective area 301b corresponding to the disk ID as described above are not formed on the outermost peripheral portion of the thermal surface, the optical disk D is a general optical disk (CD) having no thermal surface. -R etc.). When the disk ID cannot be acquired in this way, the control unit 16 determines that the optical disk D is incapable of forming a visible image (step Sa4), and performs processing for notifying the user of that fact.

  On the other hand, if the disk ID can be obtained from the optical disk D, the host PC 110 waits until an image formation instruction including image data is received (step Sa5). Performs initialization control for forming a visible image on the heat-sensitive surface of the optical disc D (step Sa6). More specifically, the control unit 16 controls the servo circuit 13 so that the spindle motor 11 is rotated at a predetermined angular velocity, or moves the optical pickup 10 to the initial position on the innermost peripheral side in the radial direction of the optical disc D. The instruction for sending is sent to the motor controller 32 to drive the stepping motor 30.

  Further, in the initialization control for image formation, the control unit 16 performs focus control so that a laser beam having a larger beam spot diameter is applied to the heat-sensitive surface of the optical disc D than when information is recorded on the recording surface. Is instructed to the servo circuit 13.

  The focus control content when the target value as described above is instructed will be described in more detail as follows. As described above, the focus control by the servo circuit 13 is performed based on the signal output from the light receiving element 56 of the optical pickup 10. When recording information on the recording surface of the optical disc D, the servo circuit 13 is focused so that circular return light (A in the figure) is received at the center of the four areas 56a, 56b, 56c, and 56d of the light receiving element 56 shown in FIG. The actuator 64 (see FIG. 3) is driven. That is, the focus actuator 64 is driven so that (a + c) − (b + d) = 0 when the received light amounts of the areas 56a, 56b, 56c, and 56d are a, b, c, and d.

  On the other hand, when a visible image is formed on the heat-sensitive surface of the optical disc D, focus control is performed so that the heat-sensitive surface is irradiated with a laser beam having a diameter larger than that during information recording on the recording surface as described above. When the shape of the return light received by the light receiving element 56 shown in FIG. 13 is an elliptical shape (B or C in the figure), the spot size of the laser light is larger than that in the case of the circle A, so the servo circuit 13 drives the focus actuator 64 so that the elliptical return light is received by the light receiving element 56. That is, the focus actuator 64 is driven so as to satisfy (a + c) − (b + d) = α (α is not 0). Therefore, in the present embodiment, the control unit 16 and the servo circuit 13 constitute beam spot control means.

  As described above, in the initialization control for visible image formation described above, the control unit 16 instructs the servo circuit 13 to set α (not 0), so that a laser having a spot diameter larger than that at the time of recording information on the recording surface. Light can be applied to the heat-sensitive surface of the optical disc D. As described above, when a visible image is formed on the heat-sensitive surface of the optical disc D, the following effects can be obtained by irradiating the laser beam with a larger spot diameter than when recording information on the recording surface. That is, in this embodiment, when forming a visible image, laser light is irradiated while rotating the optical disc D, as in the case of recording information on the recording surface. Therefore, by increasing the beam spot diameter of the laser beam, a visible image can be formed on the entire area of the heat-sensitive surface of the optical disc D in a shorter time. The reason for this will be described with reference to FIG. As schematically shown in the figure, when comparing the case where the beam spot diameter BS of the laser beam to be irradiated is large and small, the area of the region to be image-formed when the optical disk D is rotated once is the beam. When the spot diameter BS is large, it becomes larger. For this reason, when the beam spot diameter BS is small, the optical disk D has to be rotated more in order to make the entire area the target of image formation (in the example shown in the figure, when the beam spot diameter BS is large, it is 4 rotations, and when it is small, 6 rotations). ), It takes a lot of time for image formation. For the reasons described above, the optical disc recording apparatus 100 is configured to irradiate a laser beam having a larger spot diameter than that during information recording when forming a visible image.

  Further, in the initialization control for image formation, the control unit 16 sets the target value of each level to the laser power so that the laser light of the write level and the servo level corresponding to the acquired disk ID is emitted from the optical pickup 10. The control circuit 20 is instructed. That is, the ROM of the control unit 16 stores a target value to be set as a write level and a servo level for each of a plurality of types of disk IDs. The control unit 16 stores the write level and the write level corresponding to the acquired disk ID. The servo level target values are read out, and these target values are instructed to the laser power control circuit 20.

  The power target value is set in accordance with the disk ID as described above for the following reason. That is, it is conceivable that the characteristics of the thermal film used as the thermal layer 205 (see FIG. 1) differ depending on the type of the optical disc D. If the characteristics are different, the characteristic is that when the laser beam is irradiated to what extent, the color changes. Of course, it will change. For this reason, even when the light-sensitive layer 205 of a certain optical disk D is irradiated with a laser beam of a certain light level and its irradiation area can be sufficiently changed in color, On the other hand, when the laser beam of the same light level is irradiated, the irradiation area cannot always be changed. Therefore, in the present embodiment, the target values of the write level and the servo level that allow accurate image formation are obtained in advance by experiment for each optical disk corresponding to each of various disk IDs as described above. Then, by storing the obtained target value in the ROM in association with each disk ID, optimal power control can be performed according to the characteristics of the heat-sensitive layer 205 of various optical disks D as described above. I am doing so.

  When the initialization control as described above is performed by the control unit 16, a process for actually forming a visible image on the heat-sensitive surface of the optical disc D is performed. As shown in FIG. 11, the control unit 16 first transfers the image data supplied from the host PC 110 via the buffer memory 36 to the FIFO memory 34 (step Sa7). Then, the control unit 16 determines from the FG pulse signal supplied from the frequency generator 21 whether the predetermined reference position of the optical disc D rotated by the spindle motor 11 has passed the laser light irradiation position of the optical pickup 10. Is determined (step Sa8).

  Here, a method for detecting whether or not the predetermined reference position and the laser beam irradiation position have passed the position will be described with reference to FIGS. 15 and 16. As shown in FIG. 15, the frequency generator 21 outputs a predetermined number (eight in the illustrated example) of FG pulses while the spindle motor 11 rotates once, that is, while the optical disk D rotates once. Accordingly, the control unit 16 outputs a reference position detection pulse by synchronizing one of the FG pulses supplied from the frequency generator 21 with the rising timing of the reference pulse, and then makes one rotation from the reference position detection pulse. A reference position detection pulse signal for outputting a reference position detection pulse is generated in synchronization with the rising timing of the minute number (eighth in the illustrated example) pulse. By generating such a reference position detection pulse, it is possible to detect that the time when the pulse is generated is the timing at which the laser light irradiation position of the optical pickup 10 has passed the reference position of the optical disc D. That is, as shown in FIG. 16, the laser beam irradiation position of the optical pickup 10 at the timing when the first reference position detection pulse is generated is indicated by a thick line in the drawing (the optical pickup 10 is movable in the radial direction, so the irradiation position is If the reference position detection pulse generated after one rotation is generated, the laser light irradiation position of the optical pickup 10 is naturally indicated by a thick line in the figure. In position. In this way, the radial line to which the laser beam irradiation position belongs becomes the reference position at the timing at which the reference position detection pulse is first generated, and the control unit 16 is generated each time the optical disk D rotates as described above. It is possible to detect that the irradiation position of the laser light has passed the reference position of the optical disc D based on the reference position detection pulse signal. In the figure, the alternate long and short dash line shows an example of the movement trajectory of the irradiation position of the laser beam from the generation of a reference position detection pulse to the generation of the next reference position detection pulse.

  After receiving the image formation instruction from the host PC 110, when it is detected that the reference position of the optical disc D has passed the laser light irradiation position by the above-described method, the control unit 16 sets 1 to the variable R indicating the rotation speed. After the increment (step Sa9), it is determined whether or not R is an odd number (step Sa10).

  Here, when it is first detected that the reference position has been passed after receiving the image formation instruction, R = 0 (initial value) + 1 = 1. In this case, R is an odd number in step Sa10. It will be determined. When it is determined that R is an odd number in this way, the control unit 16 performs control for forming a visible image by irradiating the heat-sensitive surface of the optical disc D from the optical pickup 10 with a laser beam (step Sa11). More specifically, the control unit 16 receives the above reference position detection pulse and outputs each unit so as to sequentially output the image data from the FIFO memory 34 in synchronization with the clock signal output from the PLL circuit 33. Control. By this control, as shown in FIG. 17, the FIFO memory 34 outputs information indicating the gradation of one coordinate to the drive pulse generator 35 every time a clock pulse is supplied from the PLL circuit 33, and the drive pulse The generation unit 35 generates a drive pulse having a pulse width according to the gradation shown in the information and outputs the drive pulse to the laser driver 19. As a result, the optical pickup 10 irradiates the heat-sensitive surface of the optical disk D with the laser light at the light level for a time corresponding to the gradation of each coordinate, and the irradiation area changes color, thereby causing a visible image as shown in FIG. Can be formed.

  As schematically shown in the figure, the optical disk D is rotated by the spindle motor 11, so that the laser beam irradiation position of the optical pickup 10 is one cycle of the clock signal (the rising edge of the next pulse from the rising edge of the pulse). During the period until the timing), it moves along the circumference by the area indicated by C in the figure. By changing the time during which the laser beam is irradiated at the light level while the laser beam irradiation position passes through the region C according to the gradation level as described above, the gradation level varies depending on the region C as shown in the figure. Different areas can be discolored accordingly. In this way, a visible image corresponding to image data is formed on the heat-sensitive surface of the optical disc D by controlling the irradiation time of the light level laser light when passing through each region C according to the gradation of each coordinate. It can be done.

  As described above, when the control for executing the formation of the visible image by the laser light irradiation controlled according to the image data is executed, the process of the control unit 16 returns to Step Sa7, and the image data supplied from the buffer memory 36 Is transferred to the FIFO memory 34. Then, it is detected whether or not the laser light irradiation position of the optical pickup 10 has passed through the reference position of the optical disc D, and when it is detected that the reference position has been passed, 1 is incremented to R. As a result, when R becomes an even number, the control unit 16 controls each unit of the apparatus so as to stop the visible image formation by the laser light irradiation control as described above (step Sa12). More specifically, the FIFO memory 34 is controlled not to output information indicating the gradation of each coordinate to the drive pulse generator 35 in synchronization with the clock signal supplied from the PLL circuit 33. In other words, the control unit 16 irradiates the heat-sensitive surface of the optical disk D with light level laser light to form a visible image, and then changes the color of the heat-sensitive surface during the next rotation of the optical disk D. The laser light is controlled not to be irradiated.

  When the laser beam irradiation for forming the visible image is stopped in this way, the control unit 16 instructs the motor controller 32 to move the optical pickup 10 to the outer peripheral side in the radial direction by a predetermined amount (step Sa13). In response to the instruction, the motor controller 32 drives the stepping motor 30 via the motor driver 31, whereby the optical pickup 10 is moved to the outer peripheral side by a predetermined amount.

  Here, the predetermined amount by which the optical pickup 10 is moved in the radial direction of the optical disc D may be appropriately determined according to the beam spot diameter BS (see FIG. 14) irradiated from the optical pickup 10 as described above. That is, when a visible image is formed on the heat-sensitive surface of the disk-shaped optical disc D, the laser light irradiation position of the optical pickup 10 can be moved on the surface of the optical disc D with almost no gap, thereby realizing higher-quality image formation. It is necessary to do. Therefore, if the unit movement amount of the optical pickup 10 in the radial direction as described above is substantially the same as the beam spot diameter BS of the irradiation laser light with respect to the optical disc D, the laser light can be emitted on the surface of the optical disc D with almost no gap. Irradiation is possible, and higher-quality image formation is possible. In some cases, the area larger than the irradiated beam spot diameter may be colored due to various factors such as the nature of the heat-sensitive surface. In such a case, considering the width of the colored area, adjacent colored areas do not overlap. The unit movement amount may be determined as follows. In this embodiment, since the beam spot diameter BS is larger than that during recording on the recording surface (for example, about 20 μm), the control unit 16 reduces the diameter of the optical pickup 10 by substantially the same length as the beam spot diameter BS. The motor controller 32 is controlled to move in the direction, and the stepping motor 30 is driven. The stepping motor 30 in recent years can control the movement amount in units of 10 μm by using the μ step technology, and the optical pickup 10 can be controlled in units of 20 μm using the stepping motor 30 as described above. Moving in the radial direction is sufficiently feasible.

  When the control for moving the optical pickup 10 by a predetermined amount in the radial direction is performed as described above, the control unit 16 is configured to irradiate the laser beam at the light level so as to change the light level value of the target laser beam. The changed light level value to be targeted is instructed to the laser power control circuit 20 (step Sa14). In the present embodiment, a CAV method in which a laser beam is irradiated while rotating an optical disk D while maintaining a constant angular velocity is adopted as a method for forming a visible image. When moved to, the linear velocity increases. Therefore, when the optical pickup 10 is moved in the radial direction (outer peripheral side) in this way, the target value of the light level is changed to be larger than that at that time as described above, whereby the linear velocity is changed. Even if the temperature changes, the heat sensitive surface of the optical disk D can be irradiated with a laser power having such an intensity that the color can be sufficiently changed.

  As described above, when the movement control in the radial direction of the optical pickup 10 and the control for changing the target value of the light level are executed, the control unit 16 performs unprocessed image data, that is, the drive pulse generation unit 35 for forming a visible image. It is determined whether or not there is image data not supplied to the image. If there is no image data, the process is terminated.

  On the other hand, if there is unprocessed image data that has not been supplied to the motor controller 32, the process returns to step Sa7 to continue the process for visible image formation. That is, image data is transferred from the control unit 16 to the FIFO memory 34 (step Sa7), and it is determined whether or not the irradiation position of the laser beam has passed the reference position of the optical disc D (step Sa8). When the reference position is passed, the variable R indicating the number of rotations is incremented by 1 (step Sa9), and it is determined whether or not the incremented R is an odd number (step Sa10). Here, when R is an odd number, the control unit 16 controls each part of the apparatus so that the laser beam irradiation for forming a visible image as described above is performed. When R is an even number, the visible image is displayed. Is stopped (servo level laser light is irradiated), and control such as the above-described movement control of the optical pickup 10 in the radial direction and change of the light level target value is performed. That is, when the control unit 16 performs laser light irradiation (including the light level) for image formation on the optical disc D during a certain round, laser light irradiation for image formation is performed during the next round. Is controlled so that the optical pickup 10 is controlled to move in the radial direction during the rotation. In this way, by performing control for moving the optical pickup 10 during the lap when image formation is not performed, control for changing the light level target value, and the like, the irradiation position, the power value of the laser light to be irradiated, etc. No image is formed while the angle fluctuates, and laser beam irradiation for image formation can be executed after the irradiation position and the intensity of the laser beam are stabilized. Therefore, it is possible to suppress degradation of the quality of the visible image formed due to the radial movement control of the optical pickup 10 as described above.

  What has been described above is the main operation of the optical disc recording apparatus 100 according to the present embodiment. According to the optical disc recording apparatus 100, information is recorded on the recording surface without newly installing printing means or the like. In order to form a visible image corresponding to image data by irradiating the heat-sensitive surface of the optical disk D on which the heat-sensitive surface is formed, using each part of the apparatus such as the optical pickup 10 used for the purpose as much as possible. Can do.

  In this embodiment, the laser light irradiation timing is set based on the clock signal generated using the FG pulse generated according to the rotation of the spindle motor 11, that is, the clock signal generated according to the rotation amount of the optical disc D. Since the control is performed, it is possible to grasp the laser beam irradiation position in the optical disc recording apparatus 100 without acquiring position information or the like from the optical disc D side. Therefore, according to the optical disc recording apparatus 100, there is no restriction that the optical disc D subjected to special processing such as forming a pre-groove (guide groove) on the heat-sensitive surface must be used, and pre-groove, position information, etc. A visible image corresponding to the image data can be formed even on a heat-sensitive surface that is not formed in advance.

C. Modifications The present invention is not limited to the above-described embodiment, and various modifications as exemplified below are possible.

(Modification 1)
In the above-described embodiment, the laser light irradiation time is controlled according to the gradation level for each coordinate included in the image data corresponding to the visible image supplied from the host PC 110, so that the optical disk D is formed on the heat-sensitive surface. The shade of the visible image is expressed, but the light level of the laser power to be irradiated may be changed according to the information indicating the gradation for each coordinate to express the shade of the visible image. For example, as shown in FIG. 19, the heat-sensitive surface of the optical disc D (heat-sensitive layer 205: see FIG. 1) has a characteristic that the degree of discoloration changes gradually according to the amount of heat energy applied. If so, by adding different energy such as energy E1, E2, E3, the degree of discoloration of the heat sensitive surface also changes as D1, D2, D3. Therefore, for the optical disc D on which the heat-sensitive surface having the above characteristics is formed, by changing the light level value of the laser beam to be irradiated according to the gradation degree for each coordinate indicated in the image data, Each coordinate position on the optical disc D can be changed in color according to the gradation, thereby expressing light and shade.

  In addition to the method of changing the light level value according to the gradation as described above, a plurality of adjacent coordinates as described below are regarded as one unit area for expressing the gradation, and the unit area includes The shade of the visible image formed on the heat-sensitive surface of the optical disc D may be expressed by controlling the irradiation time of the laser light with respect to each of a plurality of included coordinates in association with the difference. More specifically, as schematically shown in FIG. 20, in the optical disc recording apparatus 100 according to the present embodiment, the laser beam irradiation position of the optical pickup 10 is indicated by a circular path TR (indicated by a one-dot chain line in the figure). A plurality of rotations are relatively moved along the line, and the power value of the laser beam irradiated during the movement is appropriately switched between the light level and the servo level according to the image data, thereby forming a visible image.

  In this modification, a fan-shaped region including a predetermined number (three in the illustrated example) of circumferential paths TR belonging to each of the fan-shaped portions obtained by dividing the optical disk D into a plurality of fan-shaped portions is defined as a unit region TA (thick line in the figure). The irradiation timing of the laser light applied to each of the three circumferential paths TR belonging to the unit area TA is controlled so that the density is expressed for each unit area TA in the visible image.

  For example, in the case of forming an image that expresses the density of a certain unit area TA, as shown in the upper part of FIG. In this case, image data is generated so that the drive pulse is generated by the drive pulse generator 35 as shown in the lower part of FIG. Control is performed such that light level laser light continues to be radiated while the laser light irradiation position passes through the three circumferential paths TR to which it belongs.

  On the other hand, when forming an image in which the density of the unit area TA is expressed very light (density is not 0), as shown in the upper part of FIG. 22, of the three circumferential paths TR belonging to the unit area TA. The laser beam irradiation time is controlled so that only a small portion of the innermost circumferential path TR is discolored, that is, as shown in the lower part of FIG. Image data is generated so that the drive pulse generation unit 35 generates a drive pulse that is irradiated with a light level laser beam only during a part of the time during which the laser beam passes.

  Further, when the density of the unit area TA is set to an intermediate density, as shown in the upper part of FIG. 23, among the three circumferential paths TR belonging to the unit area TA, the innermost circumferential path The irradiation time of the laser beam is controlled so that all parts of TR change color and half of the intermediate circumferential path TR changes color. That is, as shown in the lower part of FIG. 23, the time during which the laser beam irradiation position passes through the inner circumferential path TR of the circumferential path TR and the laser beam irradiation position passes through the intermediate circumferential path TR. Image data is generated so that the drive pulse generator 35 generates a drive pulse that is irradiated with the laser light at the light level for a part of the current time.

  In the host PC 110, image data that can express gradation for each unit area TA as described above is generated in advance, and the image data is supplied to the optical disc recording apparatus 100, so that the unit area as described above is obtained. A visible image in which gradation representation for each TA is made can be formed on the heat-sensitive surface of the optical disc D.

(Modification 2)
In the above-described embodiment, when a visible image is formed by irradiating a laser beam while the optical disk D is rotated once from the reference position, the optical pickup 10 is moved by a predetermined amount toward the outer peripheral side in the radial direction. By performing the control, the laser beam irradiation position is moved so that there is almost no gap on the entire surface of the optical disk D. However, there is a case where the mechanism for driving the optical pickup 10 in the radial direction cannot control the drive amount in units of 20 μm. In an optical disk recording apparatus equipped with such a drive mechanism, the gap area where the laser beam cannot be irradiated on the optical disk D becomes large, and as a result, the quality of the visible image formed on the heat-sensitive surface of the optical disk D is degraded. become.

  Therefore, when the resolution of the driving means for moving the optical pickup 10 in the radial direction is low, by using both the movement control of the optical pickup 10 in the radial direction by the driving means and the tracking control of the optical pickup 10, The irradiation position in the radial direction of the laser beam may be controlled in a finer unit, for example, 20 μm. More specifically, as shown in FIG. 24, the optical pickup 10 is first moved to the position A by a radial driving means such as a stepping motor. Then, in a state where the optical pickup 10 is fixed at the position A, tracking control is performed so that the irradiation position in the radial direction of the laser light becomes A1. In this way, a visible image is formed by controlling the laser beam while rotating the optical disk D once with the irradiation position set to A1. When the formation of the visible image with the irradiation position set to A1 is completed, the optical pickup 10 is fixed at the position A, and the irradiation position of the laser beam is moved to the outer peripheral side by the distance a by tracking control to position the irradiation position. Set to A2. In this state, a visible image is formed by irradiating a laser beam while rotating the optical disk D once. Similarly, image formation is performed while moving the laser light irradiation position in the order of A3, A4, and A5 by tracking control while the optical pickup 10 is fixed at the position A.

  When the image formation is completed with the laser light irradiation position set to A5, the optical pickup 10 is moved to the outer peripheral side by the distance A by the driving means, and the optical pickup 10 is moved to the position B. Then, by performing tracking control with the optical pickup 10 fixed at the position B, the laser light irradiation position is sequentially moved to the outer peripheral side by a distance a, such as positions B1, B2, B3, B4, and B5. Perform image formation. Thus, by using both the movement control in the radial direction of the optical pickup 10 by the stepping motor and the tracking control, the laser beam can be used even when the resolution of the drive control of the driving means of the optical pickup 10 in the radial direction is low. Can be moved by a finer distance unit.

(Modification 3)
Further, in the optical disc recording apparatus 100 according to the above-described embodiment, the CAV method in which a visible image is formed by irradiating a laser beam while rotating the optical disc D at a constant angular velocity is employed. However, the linear velocity is constant. The CLV method may be adopted. As described above, when the CAV method is adopted, the light level value of the laser beam irradiated as the irradiation position of the laser beam moves to the outer peripheral side of the optical disc D in order to form a high-quality visible image. Although it is necessary to increase it, in the case of the CLV method, it is not necessary to change the write level value. Therefore, the image quality of the image formed on the heat-sensitive surface of the optical disc D does not deteriorate due to the fluctuation of the target laser power value.

(Modification 4)
In the above-described embodiment, the laser power control circuit 20 controls the laser power so that the laser light of the light level target value or the servo level target value is irradiated based on the light reception result of the front monitor diode 53a of the optical pickup 10. (See FIG. 7). In the above embodiment, the front monitor diode when the laser diode 53 emits with the light level as a target is used to control the intensity of the laser light emitted from the laser diode 53 to match the light level target value. The light reception result of 53a is used. Further, in order to control the intensity of the laser light emitted from the laser diode 53 so as to coincide with the servo level target value, the light reception result of the front monitor diode 53a when the laser diode 53 emits with the servo level as a target is used. It was.

  In this way, when performing laser power control with each of the write level and servo level as target values, in addition to using the light reception result of the laser beam irradiated with each level as the target value, the servo level is set as the target value. From the result of receiving the irradiated laser light, the laser power may be controlled by controlling the laser power with the light level as a target value as well as the servo level. More specifically, the laser power control circuit 20 generates laser light having the intensity of the servo level target value SM as shown in the upper part of FIG. 25 from the light reception result (current value) of the laser light emitted with the servo level as the target value. A current value SI to be supplied to the laser diode 53 in order to emit from the laser diode 53 is obtained. When the current value SI to be supplied to emit the laser beam having the servo level target value SM is obtained in this way, the relationship between the current value SI and the supply current value obtained in advance through experiments or the like and the emitted laser power is first-order. As shown in the lower part of FIG. 25, the relationship between the supply current value and the emission laser power (linear function) is derived from the slope α expressed by the function. Next, the laser power control circuit 20 uses the derived relationship and the light level target value WM set by the control unit 16 to supply a current to be supplied to the laser diode 53 in order to emit light level laser light. The value WI is obtained. When the light level laser beam is irradiated, the laser power control circuit 20 controls the laser driver 19 to supply the current value WI obtained as described above to the laser diode 53. Control for emitting light level laser light can be performed without using a light reception result of laser light emitted with the light level as a target value in this way.

  In the above-described embodiment and the modification, the laser power feedback control is performed based on the light reception result of the front monitor diode 53a when laser light is irradiated for visible image formation. Feedback control is not performed during visible image formation, laser light test irradiation is performed before visible image formation, and a current value is supplied to the laser diode 53 based on the light reception result of the front monitor diode 53a when the test irradiation is performed. Laser power control may be performed. When the time required for image formation is short, fluctuations in the optical pickup 10 and the surrounding environment (temperature) are small, and a sufficiently accurate laser can be obtained without performing feedback control as described above. In some cases, power control can be performed. Therefore, in an optical disk recording apparatus that can form an image in a short time, it is possible to employ laser power control that does not perform feedback control as described above.

(Modification 5)
In the above-described embodiment, the type of the disc set in the optical disc recording apparatus 100 is identified by reading the disc ID recorded on the outermost peripheral portion of the heat-sensitive surface of the optical disc D, and according to the identified disc type. However, the laser ID is read when the visible image is formed on the heat-sensitive surface of the optical disc D. The laser power control or the like according to the disc type identified by may be performed. In order to obtain the disc ID recorded on the lead-in of the recording surface in this way, the user first sets the optical disc D so that the recording surface faces the optical pickup 10, and the optical disc D on which the optical disc recording apparatus 100 is set. The disk ID is read from the lead-in area. Then, the optical disc recording apparatus 100 prompts the user to turn the disc over and reinsert it, and when the optical disc D is set so that the thermal surface faces the optical pickup 10, the optical disc D is read from the thermal surface of the optical disc D. A visible image may be formed by performing laser power control corresponding to the disk ID read from the in area.

(Modification 6)
As described in the above-described embodiment, the optical disc recording apparatus 100 uses each part of the apparatus such as the optical pickup 10 for performing information recording on the recording surface, and is formed on the surface opposite to the recording surface. A visible image can be formed on the surface. By the way, in the case of CD-R, the thickness of the protective layer 201 provided on the upper layer of the recording layer 202 shown in FIG. 1 is 1.2 mm, whereas the thickness of the protective layer 206 provided on the opposite surface is Very small. Therefore, as shown in FIG. 26, the distances d1 and d2 (relative positional relationship) between the position of the layer to be irradiated with the laser light of the optical disc D and the position of the optical pickup 10 are the recording surface and the heat sensitive surface. Depending on which of these is set to face the optical pickup 10 and the optical disk D is set, the difference is about 1.2 mm.

  In the focus actuator 64 (see FIG. 3) of the optical pickup 10 designed on the assumption that the distance d1 to the recording surface of the optical disc D is the focal length, the distance between the optical pickup 10 and the irradiation target surface is d2. In some cases, sufficient focus control cannot be performed. Therefore, when the optical disk D is set so that the thermal surface faces the optical pickup 10, the optical pickup is about 1.2 mm so that the distance between the thermal surface and the optical pickup 10 substantially coincides with d1. A mechanism for holding the optical disc D at a position moved in a direction away from the optical disc 10 may be provided.

  As such a mechanism, as shown in FIG. 27, an adapter (relative position adjusting means) 271 that can be mounted on the chucking portion 270 at the center of the optical disk D is used, and the heat-sensitive surface of the optical disk D is light as described above. When the optical disc D is set in the optical disc recording apparatus 100 so as to face the pickup 10, the adapter 271 may be attached to the optical disc D.

  Also, a mechanism that can move between the vicinity of the part where the optical disk D of the optical disk recording apparatus 100 is set and a position apart from the part, and a mechanism for changing the holding position of the optical disk D as described above. It is provided in the optical disc recording apparatus 100, and only when the heat-sensitive surface of the optical disc D is set to face the optical pickup 10, the mechanism is moved to the vicinity of the setting to adjust the holding position of the optical disc D. May be.

  Further, in addition to moving the holding position of the optical disk D to a position away from the optical pickup 10 by using the adapter 271 and the like as described above, as shown in FIG. A drive mechanism (relative position adjusting means) 280 for moving the position of the optical pickup 10 to a position away from the optical disk D so that the distance between the heat sensitive surface and the optical pickup 10 is d1 when the optical disk D is set in You may make it provide.

(Modification 7)
In the above-described embodiment, focus control is performed according to the return light from the optical disk D received by the light receiving element 56 (see FIG. 3) of the optical pickup 10, and recording is performed on the recording surface in this focus control. Laser light having a spot diameter larger than that of the time was irradiated onto the heat-sensitive surface of the optical disc D. In the above embodiment, in order to increase the spot diameter, the focus actuator 64 is driven so that the light reception result of the light receiving element 56 becomes the elliptical shapes B and C shown in FIG. In order to irradiate the heat-sensitive surface of the optical disc D with a laser beam having a spot diameter larger than the spot diameter when such elliptical shapes B and C are obtained as a light reception result, the four areas 56a, 56b and 56c of the light receiving element 56 , 56d, instead of focus control according to the amount of received light, focus control according to the total amount of light received in all areas of the light receiving element 56 may be performed. That is, when the spot diameter of the laser beam irradiated onto the heat-sensitive surface of the optical disc D is increased, all of the return light cannot be received by the light receiving element 56, and the light receiving element 56 receives light as indicated by a circle Z in FIG. Return light of an area larger than the area can be obtained. That is, the total amount of light received by the light receiving element 56 is reduced. Therefore, the servo circuit 13 drives the focus actuator 64 so that the total amount of light received by the light receiving element 56 is smaller than the total amount of light received when the light reception results such as circles A, ellipses B, and C shown in FIG. As a result, a laser beam having a larger spot diameter can be irradiated onto the heat-sensitive surface of the optical disc D.

(Modification 8)
Further, when a highly transparent layer is used as the heat-sensitive layer 205 (see FIG. 1) of the optical disk D, the optical disk recording apparatus 100 also uses the optical disk recording apparatus 100 even when the optical disk D is set so that the heat-sensitive surface faces the optical pickup 10. The pregroove (guide groove) formed on the recording surface of the optical disc D can be detected from the return light (reflected light) from D. More specifically, contrary to the case where the recording surface is irradiated with laser light, the return light level is high when the pregroove is irradiated with laser light, and the land portion is irradiated. The return light is small. Therefore, the pregroove can be detected by detecting the level of the return light, and as a result, tracking control can be performed along the pregroove.

  As described above, when the optical disc D is set so that the heat-sensitive surface faces the optical pickup 10, tracking control along the pre-groove formed on the opposite recording surface is possible. Laser beam irradiation control for visible image formation may be performed while moving the laser beam irradiation position along the line. When the pregroove formed on the recording surface opposite to the heat sensitive surface is detected and tracking control is performed so that the laser beam irradiation position moves along the pregroove, the rotation direction of the spindle motor 11 is changed. The optical disk D is rotated in the reverse direction, opposite to the time of recording on the recording surface. The reason for reverse rotation in this way will be described with reference to FIG. As shown in the upper part of the figure, when a spiral pre-groove PB that is clockwise when viewed from the recording surface side is formed on the recording surface of the optical disc D, as shown in the lower part of FIG. From the heat-sensitive surface side, which is the opposite surface, it appears to be formed in a counterclockwise spiral shape. Therefore, when the optical disc D is rotated from the innermost circumferential position PBS along the pregroove PB in the same rotational direction as that during recording, the laser light irradiation position is moved along the pregroove PB. I can't. Therefore, when the laser light irradiation position is moved along the pre-groove PB when a visible image is formed by irradiating the heat-sensitive surface of the optical disc D with laser light, recording is performed on the recording surface. The optical disk D is rotated in the opposite direction to the time.

  Therefore, in the case where the visible image formation similar to the above embodiment is performed by controlling the irradiation timing and power of the laser light according to the image data while moving the irradiation position of the laser light along the pregroove PB. The control unit 16 may instruct the servo circuit 13 to rotate the spindle motor 11 in the direction opposite to that during recording on the recording surface.

  Further, when a visible image is formed on the heat-sensitive surface while moving the laser beam irradiation position along the pregroove PB formed on the recording surface as described above, the laser beam irradiation start position is set to the highest position of the pregroove PB. If the outer peripheral side position PBE is used, the laser light irradiation position can be moved along the pregroove PB even if the rotation direction of the optical disk D is the same as that during recording.

(Modification 9)
In the embodiment described above, the control unit 16 irradiates a predetermined prohibited area KA on the heat-sensitive surface of the optical disc D shown in FIG. 31 with laser light (light level laser light) for image formation. You may make it control so that it may not. As shown in the figure, when the laser beam irradiation position is moved clockwise from the reference position (see FIG. 16) described above, the prohibition area KA has a predetermined angle θ in the counterclockwise direction from the reference position. This is a fan-shaped area. That is, by rotating the optical disk D, when laser light irradiation for forming a visible image is performed while moving the laser light irradiation position from the reference position, the laser beam immediately before the laser light irradiation position returns to the reference position. A region through which the light irradiation position passes is a prohibited region KA.

  As control for prohibiting the formation of a visible image in such a prohibited area KA, the control unit 16 changes the gradation level of coordinates belonging to the prohibited area KA in the image data supplied from the host PC 110 to “0”. It is sufficient to perform data conversion such as. If such data conversion is performed, even if the drive pulse generation unit 35 faithfully generates the drive pulse according to the data, the light level laser beam is not irradiated when the laser beam irradiation position passes through the prohibited area KA. As a result, no visible image is formed in the prohibited area KA.

  As described above, the following effects can be obtained by not irradiating the prohibited area KA with the laser beam for forming the visible image. That is, even when image formation is performed in synchronization with the clock signal supplied from the PLL circuit 33 as described above, the rotational speed during the one rotation of the spindle motor 11 slightly fluctuates. The period of the clock signal output from 33 may fluctuate. Due to the fluctuation of the clock signal, which is a synchronization signal for image formation in this way, as shown in FIG. 31, the laser beam irradiation is substantially performed after the laser beam for forming the visible image is started from the reference position KK. The position trajectory (indicated by the alternate long and short dash line in the figure) rotates once, and the laser beam irradiated to express the image of the position KC immediately before the reference position is irradiated to the position KT that has passed the reference position. Can happen. In other words, the laser light that is originally irradiated to express the image at the position KC immediately before the reference position is irradiated to the position KT in the region that has already been irradiated with the laser light for forming a visible image. Laser light irradiation is performed, and as a result, a defect may occur in the formed visible image. Therefore, even when the clock signal generated by the PLL circuit 33 fluctuates, by converting the image data so that the prohibited area KA as described above is set, the visible image is formed twice at the same position. Therefore, it is possible to prevent a problem such as irradiation with a laser beam.

(Modification 10)
Further, instead of the optical disc recording apparatus 100 according to the above-described embodiment, an optical disc recording apparatus 100 ′ configured as shown in FIG. 32 may be used. As shown in the figure, the difference between this optical disk recording apparatus 100 ′ and the optical disk recording apparatus 100 in the above embodiment is that it does not have the FIFO memory 34 and the drive pulse generation unit 35, and instead of the encoder 17. The encoder 320 is provided.

  The encoder 320 is a circuit that performs EFM modulation, CIRC (Cross Interleave Reed-Solomon Code) conversion, and the like on the supplied data, like the encoder 17 in the above-described embodiment, and temporarily stores the supplied data. The data is subjected to the modulation processing as described above and output to the strategy circuit 18 ′. Further, the encoder 320 performs processing such as EFM modulation on the data supplied from the buffer memory 36 based on the modulation on / off signal supplied from the control unit 16, or outputs the processed data, or performs EFM modulation or the like. It is configured to be able to switch whether to output data without using it. When a signal indicating modulation on is supplied from the control unit 16, the encoder 320 performs EFM modulation or the like on the data supplied from the buffer memory 36 and outputs the data to the strategy circuit 18. On the other hand, when the modulation off signal is supplied from the control unit 16, the encoder 320 does not modulate the data supplied from the buffer memory 36, and the data is synchronized with the clock signal supplied from the PLL circuit 33. Output.

  The control unit 16 outputs a modulation on / off signal to the encoder 320 in accordance with an instruction from a user input via a user interface (not shown) or the like. More specifically, when receiving an instruction from the user to form a visible image on the heat-sensitive surface, a modulation off signal is output, and the user instructs to record information on the recording surface. If received, a modulation on signal is output. As described above, the control unit 16 may output the modulation on / off signal in accordance with an instruction from the user. However, depending on which surface the optical disc D is set to face the optical pickup 10 Accordingly, a modulation on / off signal may be output. In this case, when the optical disk D is set so that the thermal surface faces the optical pickup 10, a modulation off signal is output, and when the recording surface is set on the optical disk D so as to face the optical pickup 10, the modulation on signal is output. What is necessary is just to output.

  Under the above configuration, when the user instructs to record information on the recording surface, the control unit 16 outputs a modulation ON signal to the encoder 320. Then, recording data to be recorded on the recording surface of the optical disc D is supplied from the host PC 110 to the buffer memory 36 and transferred from the buffer memory 36 to the encoder 320. Upon receiving the modulation ON signal, the encoder 320 performs EFM modulation or the like on the recording data supplied from the buffer memory 36 and outputs it to the strategy circuit 18. The strategy circuit 18 ′ corrects the time axis of the EFM-modulated data, generates a drive pulse for driving the laser driver 19, and outputs it to the laser driver 19. In response to this drive pulse, the laser driver 19 supplies a drive current to the laser diode 53 (see FIG. 3) of the optical pickup 10 to irradiate the optical pickup 10 with laser light, and the recording surface of the optical disc D is subjected to the host. Recording of recording data supplied from the PC 110 is performed.

  On the other hand, when the user instructs to form a visible image on the heat sensitive surface, the control unit 16 outputs a modulation off signal to the encoder 320. Then, image data corresponding to a visible image to be formed on the heat-sensitive surface of the optical disc D is supplied from the host PC 110 to the buffer memory 36 and transferred from the buffer memory 36 to a memory built in the encoder 320. Receiving the modulation off signal, the encoder 320 does not perform processing such as modulation on the image data transferred from the buffer memory 36, and synchronizes with the clock signal supplied from the PLL circuit 33. Information indicating the gradation) is sequentially output to the strategy circuit 18. The strategy circuit 18 ′ generates a drive pulse based on the data indicating the gradation level for each coordinate sequentially supplied to the laser driver 19 in the same manner as the drive pulse generation unit 35 in the above-described embodiment. Output. In response to this drive pulse, the laser driver 19 supplies a drive current to a laser diode 53 (see FIG. 3) of the optical pickup 10 to irradiate the optical pickup 10 with laser light, and the host is applied to the thermal surface of the optical disc D. Visible image formation corresponding to the image data supplied from the PC 110 is performed.

  As described above, by making it possible to switch whether or not the encoder 320 performs modulation between the case where a visible image is formed and the case where information is recorded, a FIFO memory used only for visible image formation. 34 and the drive pulse generation unit 35 can be omitted, and the optical disc recording apparatus 100 ′ can have a visible image forming function and an information recording function while having a simpler configuration.

(Modification 11)
A visible image may also be formed on the recording surface (recording layer 202) of the optical disc D. As is well known, when the recording layer 202 is irradiated with a laser beam having a predetermined intensity or more, the reflectance of the irradiated portion changes. Therefore, by irradiating the laser beam over a wide range that can be visually identified, a visible image is formed. Can be formed. Alternatively, if the recording layer 202 is made of a material whose state changes such that the laser light irradiation region is hollowed or raised, a visible image can be formed using the properties of the material.
When a visible image is formed on the recording surface (recording layer 202), data for forming a visible image may be recorded along a guide groove (pre-groove) formed in the recording layer 202. Alternatively, as in the case where a visible image is formed on the heat-sensitive surface (the heat-sensitive layer 205), the beam spot diameter of the laser light applied to the recording layer 202 may be adjusted to be large and recorded without using the guide groove. That is, the interval between the guide grooves (track pitch) is a narrow value of about several μm, and there is no problem that the resolution of the formed visible image is lowered even if recording along the guide grooves is not performed. In addition, since a guide groove is provided on the surface of the recording layer 205, strictly speaking, there are irregularities, but the depth of the groove is also a narrow value of about several μm. Layer 202 can be treated as a plane.
In any case, if the technique according to the present invention is used, a visible image can be formed not only on the thermal surface (thermal layer 205) but also on the recording surface (recording layer 202) without using any special apparatus. it can.

(Modification 12)
When a visible image is formed on the recording layer 202 of the optical disc D, it is naturally impossible to perform original data recording in the area where the visible image is formed. Therefore, an area for forming a visible image in the recording area (recording layer 202) of the optical disc D may be determined in advance. For example, if it is determined that original data recording is performed in the area from the innermost peripheral position of the disc to a predetermined position (address) and a visible image is formed in the outer peripheral area, the original data recording is performed. There is no inconvenience that there is no area to do.
Alternatively, after the original data recording, an unrecorded area (unrecorded area) may be detected, and a visible image may be formed in the detected unrecorded area.

(Modification 13)
Data (image data) to be recorded for forming a visible image may be stored in advance in a memory (not shown) of the optical disc recording apparatus 100. For example, data to be recorded in order to form numbers 0 to 9 as visible images on the optical disk D is prepared in a memory. Then, when the user designates a number to be formed on the optical disc D, recording data relating to the designated number may be read from the memory and recorded on the optical disc D to form a visible image.
In addition, the original data is recorded from the inner periphery to the outer periphery of the disc, and after the data recording is completed, the time stamp information related to the date and time of recording is automatically formed as a visible image without the user's instruction. It may be. The time stamp information may be supplied from the external device (host PC 110) to the optical disc recording device 100.
In addition, after the original data recording is finished, signature information indicating the user name and the content of the recorded data may be formed as a visible image. The signature information may be supplied to the optical disc recording apparatus 100 by the user operating the host PC 110. Alternatively, the user may directly input (register) signature information by operating the optical disc recording apparatus 100.

1 is a side sectional view showing a schematic configuration of an optical disc capable of forming a visible image by an optical disc recording apparatus according to an embodiment of the present invention. 1 is a block diagram showing a configuration of an optical disc recording apparatus according to an embodiment of the present invention. It is a figure which shows the structure of the optical pick-up which is a component of the said optical disk recording device. It is a figure for demonstrating the content of the image data used in order to form a visible image with respect to the heat-sensitive surface of the said optical disk by the said optical disk recording device. It is a figure for demonstrating the irradiation control content of the laser beam for expressing the contrast of an image, when the said optical disk recording device forms a visible image with respect to the heat-sensitive surface of the said optical disk. It is a figure for demonstrating the control method of the laser beam at the time of the said optical disk recording device forming a visible image with respect to the heat-sensitive surface of the said optical disk. It is a figure for demonstrating the laser power control content by the laser power control circuit which is a component of the said optical disk recording device. It is a figure which shows the return light of the laser beam irradiated to the heat sensitive surface of the said optical disk from the optical pick-up of the said optical disk recording device. It is a figure which shows the FG pulse produced | generated according to the rotation amount of a spindle motor by the frequency generator 21 which is a component of the said optical disk recording device, and the clock signal produced | generated based on the said FG pulse. 4 is a flowchart for explaining the operation of the optical disc recording apparatus. 4 is a flowchart for explaining the operation of the optical disc recording apparatus. It is a figure which shows disk ID recorded on the thermal surface of the said optical disk. It is a figure which shows the shape of the return light of the laser beam received by the light receiving element of the said optical pick-up of the said optical disk recording device. It is a figure for demonstrating the size of the beam spot diameter of the laser beam which the said optical pick-up of the said optical disk recording device irradiates to the said heat-sensitive surface of the said optical disk. It is a figure for demonstrating the method to detect that the laser beam irradiation position of the said optical disk recording device passed the reference position of the said optical disk. It is a figure for demonstrating the method to detect that the laser beam irradiation position of the said optical disk recording device passed the reference position of the said optical disk. 4 is a timing chart for explaining the operation of the optical disk recording apparatus when a visible image is formed by irradiating a laser beam onto a heat sensitive surface of the optical disk. It is a figure which shows the heat sensitive surface of the said optical disk irradiated with the laser beam by the said optical disk recording device. It is a figure for demonstrating the method of expressing the contrast of the visible image formed in the heat-sensitive surface of the said optical disk with the said optical disk recording device. It is a figure for demonstrating the method of expressing the contrast of the visible image formed in the heat-sensitive surface of the said optical disk with the said optical disk recording device. It is a figure for demonstrating the method of expressing the contrast of the visible image formed in the heat-sensitive surface of the said optical disk with the said optical disk recording device. It is a figure for demonstrating the method of expressing the contrast of the visible image formed in the heat-sensitive surface of the said optical disk with the said optical disk recording device. It is a figure for demonstrating the method of expressing the contrast of the visible image formed in the heat-sensitive surface of the said optical disk with the said optical disk recording device. It is a figure for demonstrating the method to move the irradiation position of a laser beam to the radial direction of the said optical disk, when forming a visible image on the heat-sensitive surface of the said optical disk with the said optical disk recording device. It is a figure for demonstrating the laser power control content implemented by the said optical disk recording device. When the optical disk is set in the optical disk recording device so that the thermal surface faces the optical pickup, and when the optical disk is set so that the surface opposite to the thermal surface faces the optical pickup, It is a figure which shows the positional relationship of the said optical disk and the said optical pick-up. It is an external view which shows the adapter for adjusting the positional relationship of the said optical disk and the said optical pick-up. It is a figure which shows schematic structure of the optical disk recording device provided with the function to adjust the positional relationship of the said optical disk and the said optical pick-up. It is a figure for demonstrating the method for enlarging the beam spot diameter of the laser beam irradiated to the heat-sensitive surface of the said optical disk. It is a figure for demonstrating the method of moving the irradiation position of a laser beam along the pregroove on the recording surface formed in the surface on the opposite side to the heat-sensitive surface of the said optical disk, and performing the said visible image formation. It is a figure for demonstrating the prohibition area | region of the said optical disk for which the laser beam irradiation for the visible image formation by the said optical disk recording device is prohibited. It is a block diagram which shows the structure of the modification of the said optical disk recording device.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Optical pick-up, 11 ... Spindle motor (rotation drive means), 12 ... RF amplifier, 13 ... Servo circuit, 16 ... Control part, 17 ... Encoder, 18 ... Strategy circuit, 19 ... Laser Driver, 20 ... Laser power control circuit, 21 ... Frequency generator, 30 ... Stepping motor, 31 ... Motor driver, 32 ... Motor controller, 33 ... PLL circuit, 34 ... FIFO memory, 35 ... Drive pulse generation unit 36... Buffer memory 53. Laser diode 53 a front monitor diode 56 light receiving element 64 focus actuator 65 tracking actuator 100 optical disk recording device 201 ... Protective layer, 202 ... Recording layer, 203 ... Reflective layer, 204 ... Protective layer Layers, 205 ...... thermosensitive layer, 206 ...... protective layer, 270 ...... chucking unit, 271 ...... adapter, 280 ...... driving mechanism, 320 ...... encoder, D ...... optical disc.

Claims (7)

In an optical disk recording apparatus for forming a visible image on the optical disk by irradiating the optical disk with laser light,
Disk rotating means for rotating the optical disk;
Rotation detection means for detecting the rotation state of the optical disc;
An optical pickup for irradiating the optical disk rotated by the disk rotating means with a laser beam;
An optical pickup moving means for moving the optical pickup by a predetermined first distance in the disk radial direction;
Tracking control means provided in the optical pickup, for controlling the laser beam irradiated by the optical pickup so that the irradiation position moves in the disk radial direction;
When the information is recorded by irradiating the optical disk with laser light , the tracking control means performs tracking servo control based on the laser light irradiated by the optical pickup, while irradiating the optical disk with laser light. When a visible image is formed by irradiation, the rotation detection unit detects one rotation of the irradiation position of the laser beam emitted from the optical pickup in a state where the radial position of the optical pickup is fixed. Each time it is moved, it is moved in the radial direction by a second distance smaller than the first distance,
The optical pickup moving means moves the optical pickup in the radial direction by the first distance when the rotation detecting means detects that the optical disk has been rotated by a predetermined number of rotations. apparatus. When forming a visible image by irradiating the optical disk with laser light , the tracking control means moves the irradiation position of the laser light to the outer peripheral side of the optical disk by the second distance. The optical disk recording apparatus according to claim 1. The optical pickup moving means moves the optical pickup to the outer peripheral side of the optical disc by the first distance when a visible image is formed by irradiating the optical disc with laser light. The optical disk recording apparatus according to claim 1 or 2. When forming a visible image by irradiating the optical disk with laser light , the tracking control means moves the irradiation position of the laser light in the disk radial direction by a distance equal to the beam spot diameter of the laser light. The optical disk recording apparatus according to claim 1, wherein the optical disk recording apparatus is a recording medium. When forming a visible image by irradiating the optical disk with laser light , the tracking control means sets the irradiation position of the laser light in a state where the radial position of the optical pickup is fixed. Each time the rotation detecting means detects one rotation, the second distance is sequentially moved to the outer peripheral side,
The optical pickup moving means sequentially moves the optical pickup to the outer peripheral side by the first distance every time the rotation detecting means detects that the optical disk has been rotated by a predetermined number of rotations. The optical disk recording apparatus according to claim 1. The optical disk recording apparatus according to claim 1, wherein the disk rotating unit rotates the optical disk at a constant angular velocity. A control method for an optical disc recording apparatus, comprising: a disc rotating means for rotating an optical disc; and an optical pickup for irradiating the optical disc with laser light, and forming a visible image on the optical disc by irradiating the optical disc with laser light. And
A first step of detecting a rotation state of the optical disk rotated by the disk rotating means;
When recording information by irradiating the optical disk with laser light, tracking servo control is performed based on the laser light irradiated by the optical pickup, while a visible image is formed by irradiating the optical disk with laser light. When the optical pickup is formed, the irradiation position of the laser beam emitted from the optical pickup in the state where the radial position of the optical pickup is fixed is detected in advance every time the optical disk is rotated once. A second step of moving in a radial direction by a second distance smaller than the determined first distance;
And a third step of moving the optical pickup in the radial direction by the first distance when it is detected that the optical disk has been rotated a predetermined number of times.

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