JP4147821B2 - Optical disc recording apparatus and optical disc - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical disc recording apparatus for forming a visible image on an optical disc surface and an optical disc therefor.
[0002]
[Prior art]
2. Description of the Related Art Optical disc recording apparatuses that record information such as music data on optical discs such as CD-R (Compact Disc-Recordable) and CD-RW (Compact Disc-Rewritable) are widely provided. An optical disc recording apparatus performs information recording by irradiating one surface (recording surface) of an optical disc with laser light to form pits corresponding to the data length on the recording surface.
[0003]
[Problems to be solved by the invention]
By the way, it is convenient if the contents recorded on each optical disc can be discriminated visually (visually). For this reason, the user has used a dedicated printer device to print, for example, the recorded music title on a circular label sheet, and this label sheet is attached to the surface opposite to the recording surface of the optical disc (hereinafter referred to as the label surface).
However, in this method, the user has to prepare a dedicated printer device. In addition, the user has been required to perform complicated operations such as recording an optical disk, taking out the optical disk from the optical disk recording apparatus, and pasting a label sheet created by a dedicated printer device.
[0004]
In recent years, an optical disk recording apparatus capable of printing characters (such as a song title) on the label surface of the optical disk is being provided. This optical disk recording apparatus irradiates a desired area on the label surface of an optical disk with laser light, and changes the color of the irradiated area to form (print) characters or the like.
However, even if such an optical disc recording apparatus is used, the user is required to perform complicated work. That is, when recording information, the user needs to set the apparatus so that the recording surface side of the optical disk is irradiated with laser light. When forming an image, the label surface of the optical disk is irradiated with laser light. Had to be set in the device. For this reason, the user has been required to perform the troublesome work of taking out the optical disk from the apparatus after recording the information, turning the optical disk over and resetting it.
[0005]
The present invention has been made in consideration of the above circumstances, and can record information and print characters (formed as a visible image) on the optical disc, and turn the optical disc over to the user. An object of the present invention is to provide an optical disk recording apparatus that does not require a troublesome work such as resetting, and an optical disk for the apparatus.
[0006]
[Means for Solving the Problems]
In order to solve the above problems, an optical disk recording apparatus according to the present invention includes a recording layer for recording information on one side, a color changing layer whose color changes by heat on the other side, and the recording layer and the color changing layer. Rotating means for rotating an optical disk on which a semi-transmissive material is formed between each of them, and irradiating a laser beam from the one surface to the optical disk rotated by the rotating means, and movable in a substantially radial direction of the optical disk Optical pickup and means for adjusting the level of laser light emitted from the optical pickup when a visible image is formed on the discoloration layer, the optical disk based on image data representing the visible image to be formed Hardly changes the recording layer and the discoloration layer Depending on the transmissivity of the translucent material The first intensity or the recording layer is hardly changed and the color of the color changing layer is changed. Depending on the transmissivity of the translucent material And a laser beam level control means for adjusting the level of the laser beam emitted from the optical pickup so as to have one of the second intensities.
According to this apparatus, a recording layer for recording information on one side, a color changing layer whose color changes by heat on the other side, and a translucent material are formed between the recording layer and the color changing layer, respectively. When an optical disc is set, information can be recorded by irradiating the recording layer with laser light in the same manner as before, and a visible image can be formed on the color changing layer. Furthermore, since information recording and visible image formation can be performed by irradiating laser light from the same surface of the optical disk, the user does not need to perform troublesome operations such as turning the optical disk over and resetting it.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
A. Configuration of the embodiment
The optical disc recording apparatus according to the present embodiment has a function of forming a visible image such as characters on the optical disc in addition to a general recording function for recording music data or the like on the optical disc. Hereinafter, the configuration of the optical disc to be recorded by the optical disc recording apparatus according to the present embodiment will be described, and then the configuration of the optical disc recording apparatus according to the present embodiment will be described.
[0009]
(Configuration of optical disc)
FIG. 1 is a side sectional view of an optical disc (here, a CD-R disc is assumed) 200 assumed in the present embodiment. As shown in FIG. 1, the optical disc 200 includes a protective layer 201, a recording layer 202, a transflective layer 203, a protective layer 204, a color changing layer 205, a reflective layer 206, and a protective layer 207. The structure which laminated | stacked these is taken. FIG. 1 schematically shows the structure of the optical disc 200, and the dimensional ratio of each layer is not as shown in this figure. In the following description, the surface of the optical disc 200 on which the protective layer 201 is formed is described as a recording surface, and the surface on which the protective layer 207 is formed is described as a label surface.
[0010]
Among these layers, a groove 202a is spirally formed on the recording layer 202. When information is recorded on the optical disc 200, laser light is irradiated along the groove 202a (ON).・ Groove recording). That is, when recording information on the optical disc 200, as schematically shown in FIG. 2A, control is performed so that the laser beam is focused on the recording layer 202 (groove 202a). The laser beam is irradiated along the groove 202a. As a result, as shown in FIG. 2B, pits 202p corresponding to the recording data length are formed on the groove 202a.
Reproduction of information recorded on the optical disc 200 is controlled such that the laser beam is focused on the recording layer 202 (groove 202a), and laser light is irradiated along the groove 202a. At this time, the information recorded by demodulating the light (returned light) signal reflected from the optical disc 200 is reproduced.
[0011]
The discoloration layer 205 has a property of being discolored thermally when irradiated with laser light having a certain intensity or more (heat amount). Therefore, when a visible image is formed on the optical disc 200, as schematically shown in FIG. 3, the laser beam is applied on the color changing layer 205 so that laser light having a certain intensity or more is irradiated onto the color changing layer 205. Is condensed. Then, a visible image is formed by thermally changing a desired area on the color changing layer 205. Specific control contents when forming a visible image on the discoloration layer 205 will be described later.
[0012]
The transflective layer 203 has a property of reflecting a part of incident light and transmitting a part thereof. For example, if the transflective layer 203 has a reflectivity of 40% (transmittance of 60%), 40% of the incident light is reflected and the rest is transmitted.
In the present embodiment, by utilizing such a property of the transflective layer 203, information is recorded on and reproduced from the recording layer 202 by irradiating a laser beam from the recording surface of the optical disc 200 (see FIG. 1). In addition to this, a visible image is formed on the discoloration layer 205.
More specifically, the properties of the transflective layer 203 will be described. When a visible image is formed, the transflective layer 203 applies laser light (a part thereof) incident from the recording surface side to the discoloration layer 205. As a result, the discoloration layer 205 is irradiated with laser light, and a desired image can be formed on the discoloration layer 205.
On the other hand, when reproducing the information recorded on the recording layer 202, the transflective layer 203 reflects a part of the laser light irradiated to the recording layer 202 from the recording surface side. The recorded information is reproduced by demodulating the signal of the return light.
[0013]
Of course, when forming a visible image, the laser light incident from the recording surface side is irradiated on the color changing layer 205 and also on the recording layer 202. However, when a visible image is formed, the laser beam is focused on the discoloration layer 205 and the laser beam is not focused on the recording layer 202 as shown in FIG. The size (heat amount) per unit area of the laser light irradiated to the layer 202 is small, and adverse effects such as thermal damage to the groove 202a formed in the recording layer 202 are prevented.
Similarly, when recording information, a laser beam (a part) incident on the recording layer 202 is transmitted through the transflective layer 203 and is also irradiated on the discoloration layer 205. However, when recording information, the laser beam is focused on the recording layer 202 and the laser beam is not focused on the discoloration layer 205, as shown in FIG. The size (heat amount) per unit area of the laser light applied to the color changing layer 205 is small, and adverse effects such as a change in color development on the color changing layer 205 do not occur.
[0014]
As described above, the optical disk 200 has substantially the same configuration as that of the conventional CD-R disk except for the point that it has the color changing layer 205 and the semi-transmissive reflective layer 203 as constituent elements. . For this reason, further explanation is omitted.
In this embodiment, it is assumed that an image is formed on the discoloration layer 205 of the optical disc 200. However, as will be described later (variation example), the recording layer 202 is formed of the same material as that of the discoloration layer 205. In this case, a visible image can be formed on each of the color changing layer 205 and the recording layer 202.
[0015]
(Configuration of optical disk recording device)
FIG. 4 is a block diagram showing a configuration of the optical disc recording apparatus 100 according to the present embodiment. As shown in FIG. 4, 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, Decoder 15, controller 16, encoder 17, strategy circuit 18, laser driver 19, laser power control circuit 20, frequency generator 21, stepping motor 30, motor driver 31, 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.
[0016]
The spindle motor 11 is a motor for rotationally driving the optical disk 200 that is a target of data recording, and the number of rotations is controlled by the servo circuit 13. Since the optical disc recording apparatus 100 according to the present embodiment records data by a CAV (Constant Angular Velocity) method, the spindle motor 11 rotates at a constant angular velocity designated by the control unit 16.
[0017]
The optical pickup 10 is a unit that irradiates a laser beam to the optical disc 200 that is rotationally driven by the spindle motor 11.
FIG. 5 shows the configuration of the optical pickup 10. As shown in FIG. 5, the optical pickup 10 includes a laser diode 53 that emits a laser beam 10B, a diffraction grating 58, and an optical system for condensing the laser beam 10B onto an optical disc 200 (recording layer 202 and discoloration layer 205). 55 and a light receiving element 56 for receiving reflected light.
[0018]
In the optical pickup 10, when a drive current is supplied from the laser driver 19 (see FIG. 4), the laser diode 53 emits a laser beam 10B having an intensity corresponding to the drive current. The optical pickup 10 separates the laser beam 10B 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 divided into a polarizing beam splitter 59, a collimator lens 60, 1 / The light is condensed on the surface of the optical disc 200 through the four-wavelength plate 61 and the objective lens 62. Then, the three laser beams 10B reflected by the surface of the optical disc 200 are transmitted again through the objective lens 62, the quarter wavelength plate 61, and the collimator lens 60, reflected by the deflection 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. 4), and the received light signal is supplied to the control unit 16 and the servo circuit 13 via the RF amplifier 12.
[0019]
The objective lens 62 is held by a focus actuator 64 and a tracking actuator 65, and can move in the optical axis direction of the laser beam 10B and the radial direction of the optical disc 200. 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. 4). 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.
[0020]
Further, 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 It is supplied from the optical pickup 10 to the laser power control circuit 20 shown in FIG.
[0021]
The RF amplifier 12 amplifies the light reception signal from the optical pickup 10 and outputs the amplified signal to the servo circuit 13 and the decoder 15. When the recorded information is reproduced, this received light signal corresponds to an EFM (Eight to Fourteen Modulation) modulated RF signal. Thereafter, the decoder 15 performs EFM demodulation on the RF signal and supplies it to the control unit 16.
[0022]
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. As a driving method of the spindle motor 11 when information is recorded on the recording layer 202 (see FIG. 1) of the optical disc 200 or when a visible image is formed on the color changing layer 205 (see FIG. 1) of the optical disc 200, the optical disc 200 is used. Either a method of driving at a constant angular velocity (CAV: Constant Angular Velocity) or a method of rotating the optical disc 200 so as to have a constant recording linear velocity (CLV: Constant Linear Velocity) may be used. Since the optical disk recording apparatus 100 according to the present embodiment employs the CAV method, the servo circuit 13 rotates the spindle motor 11 at a constant angular velocity instructed by the control unit 16.
[0023]
The buffer memory 36 stores data to be recorded on the optical disc 200 supplied from the host PC 110. More specifically, when recording information, the buffer memory 36 accumulates data to be recorded in the recording layer 202 (hereinafter referred to as recording data), and outputs the accumulated recording data to the encoder 17. When a visible image is formed, data to be recorded (hereinafter referred to as image data) is accumulated in the color changing layer 205, and the accumulated image data is output to the control unit 16.
[0024]
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. 5) 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.
[0025]
The laser power control circuit 20 controls the laser power emitted from the laser diode 53 (see FIG. 5) of the optical pickup 10. Specifically, the laser power control circuit 20 controls the laser driver 19 so that the optical pickup 10 emits laser light having a value that matches the target value of the optimum laser power instructed by the control unit 16. 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.
[0026]
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.
The image data is data for forming a visible image on the surface of the disk-shaped optical disc 200. As shown in FIG. 6, each of n coordinates on a large number of concentric circles centering on the center point of the optical disc 200 is used. Information indicating the degree of gradation (shading) is described for each (indicated by black dots 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. 6 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 200 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.
[0027]
When a visible image is formed on the heat-sensitive surface of the optical disc 200 based on the image data as described above, a clock signal for image recording is supplied from the PLL circuit 33 to the FIFO memory 34. . 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.
[0028]
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. 7, a drive pulse with a reduced write level pulse width is generated. Here, the light level means a power level at which the discoloration layer 205 in the irradiated portion is clearly discolored when a laser beam having that level of power is irradiated onto the discoloration layer 205 of the optical disc 200. When a pulse is supplied to the laser driver 19, a light level laser beam 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 the wide area of the heat-sensitive surface of the optical disc 200 is discolored. As a result, the user can visually recognize that this area is a dark area. Become. In the present embodiment, the gradation shown in the image data is expressed by changing the length of the area to be changed per unit area (unit length) in this way.
[0029]
As described above, in the present embodiment, a part of the laser light incident from the recording surface (see FIG. 1) of the optical disc 200 is transmitted through the recording layer 202 and the semi-transmissive reflective layer 203 and the discoloration layer 205 is passed through. Irradiate. That is, not all of the laser light incident on the optical disc 200 irradiates the color changing layer 205, but a part thereof irradiates the color changing layer 205. Therefore, it is desirable that the level of the laser beam emitted from the optical pickup 10 is sufficiently high so that the level of the irradiation laser beam with respect to the color changing layer 205 is equal to or higher than the light level described above.
However, on the other hand, the laser light incident from the recording surface of the optical disc 200 is also applied to the recording layer 202. Therefore, when an excessively high level of laser light is applied, the laser beam is condensed on the recording layer 202. In spite of not being done, the groove 202a formed in the recording layer 202 may be thermally damaged.
Considering the above, the level of the laser light emitted from the optical pickup 10 is: (1) the discoloration layer 205 is irradiated with sufficient laser light above the light level, and (2) the recording layer. What is necessary is just to determine so that it may not produce a bad influence, such as thermally damaging the groove 202a with respect to 202, and the above two conditions may be satisfied.
[0030]
The servo level (first intensity) is a power level at which the discoloration layer 205 hardly discolors even if the discoloration layer 205 of the optical disc 200 is irradiated with laser light having that level. In this case, the servo level laser beam may be irradiated without irradiating the light level laser beam. Even when the laser beam of the servo level (first intensity) is irradiated to the color changing layer 205, the laser beam is not irradiated to the recording layer 202. The laser beam of about the servo level is irradiated, (2) the recording layer 202 is prevented from being adversely affected such as thermally damaging the groove 202a, and the above two conditions are satisfied. The laser power value may be determined.
[0031]
The drive pulse generator 35 generates a drive pulse based on the information indicating the gradation for each coordinate as described above, and also performs laser power control by the laser power control circuit 20 and focus control and tracking by the servo circuit 13. When it is necessary to carry out the control, a light level pulse or a servo level pulse for a very short period is inserted regardless of the information indicating the gradation. For example, as shown in the upper part of FIG. 8, in order to express a visible image according to the gradation of a certain coordinate in the image data, it is necessary to irradiate a laser beam 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. ) May be forcibly inserted.
Further, as shown in the lower part of FIG. 8, when it is necessary to irradiate a laser beam having 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) may be inserted after the servo cycle ST has elapsed after the level pulse is generated.
[0032]
The servo off pulse SSP1 is inserted not only for controlling the laser power but also for the purpose of performing focus control and tracking control by the servo circuit 13. That is, tracking control and focus control are based on the RF signal received by the light receiving element 56 (see FIG. 5) of the optical pickup 10, that is, the return light (reflected light) from the optical disk 200 of the laser light emitted from the laser diode 53. Done.
Here, FIG. 9 shows an example of a signal received by the light receiving element 56 when the color changing layer 205 (see FIG. 1) is irradiated with a laser beam. Thus, it is obtained when a light level laser beam is irradiated. The signal of the reflected light includes elements of the peak portion K1 at the time of rising of the laser beam and the shoulder portion K2 thereafter, the influence of laser noise is large, and the level thereof is very unstable. Such a reflected light signal cannot be used for focus control or tracking control. On the other hand, the reflected light signal obtained when the laser beam of the servo level is irradiated has a low level, so that the influence of the laser noise is small and the level is stable.
For this reason, the servo off-pulse SSP1 is forcibly inserted to irradiate the servo level laser beam so that a reflected light signal of a stable level can be obtained, and focus control and tracking control are performed using this reflected light signal. To enable each servo to be executed stably.
If the servo off-pulse SSP1 and the servo on-pulse SSP2 are inserted for a minimum time that does not hinder the execution of various servos such as laser power control, tracking control, and focus control, the visible image to be formed is inserted. There will be no adverse effects.
[0033]
Returning to FIG. 4, the PLL circuit (signal output means) 33 multiplies the FG pulse signal having a frequency corresponding to the rotational 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 from the motor driver of the spindle motor 11. For example, as shown in the upper part of FIG. 10, when the frequency generator 21 generates eight FG pulses while the spindle motor 11 makes one revolution, that is, the optical disk 200 makes one revolution, the lower part of FIG. 2, the PLL circuit 33 outputs a clock signal obtained by multiplying the FG pulse. The 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 1 is added to the clock signal. Data indicating the gradation of one coordinate is output from the FIFO memory 34 to the drive pulse generator 35 every period, that is, every time the optical disc 200 rotates by a certain angle.
[0034]
The stepping motor 30 is a motor for moving the optical pickup 10 in the radial direction of the set optical disc 200. 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 200, and the spindle motor 11 rotates the optical disc 200 with respect to the optical disc 200, so that the laser light irradiation position of the optical pickup 10 is changed to various positions on the optical disc 200. Can be moved.
[0035]
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. In addition, various processes for recording information on the recording layer 202 of the optical disc 200 and forming an image on the discoloration layer 205 of the optical disc 200 are centrally controlled.
The above is the configuration of the optical disc recording apparatus 100 according to the present embodiment.
[0036]
B. Operation of the embodiment
Next, the operation of the optical disc recording apparatus 100 configured as described above will be described.
As described above, the optical disc recording apparatus 100 has a function of recording information such as music data on the recording layer 202 of the optical disc 200 and a visible image on the discoloration layer 205 of the optical disc 200 as in the conventional optical disc recording apparatus. It has the function to form.
When the user sets the optical disc 200 in the optical disc recording apparatus 100 and is instructed to record information or form an image, the control unit 16 of the optical disc recording apparatus 100 controls each part of the apparatus to move the optical disc 200 at a predetermined speed. While rotating, the optical disc 200 is irradiated with a predetermined level of laser light to realize information recording or image formation.
Among the series of operations, the optical disk recording layer 200 according to the present invention is most characterized by the condensing control of the laser beam 10B with which the optical disk 200 is irradiated, that is, the focus control. The operation will be described with a focus on.
[0037]
(Operation details of focus control)
When recording information on the optical disc 200, the control unit 16 performs focus control so that the laser beam 10B incident on the recording surface of the optical disc 200 is focused on the recording layer 202 (groove 202a). . Further, when forming a visible image on the optical disc 200, focus control is performed so that the laser beam 10 </ b> B incident on the recording surface of the optical disc 200 is focused on the discoloration layer 205. Here, since the content of focus control when recording information is the same as that of a conventional optical disk recording apparatus, the concept will be briefly described below, and then the content of focus control when forming a visible image will be described. explain.
[0038]
(Focus control when recording information)
The control unit 16 drives the focus actuator 64 to adjust the position of the objective lens 62 so that the laser beam 10B is focused on the recording layer 202 (groove 202a) of the optical disc 200. More specifically, the control unit 16 drives the focus actuator 64 to move the objective lens 62 located away from the optical disk 200 so as to gradually approach the optical disk 200. FIG. 11 shows the relationship between the position of the objective lens 62 and the condensing position of the laser beam 10B. Thus, as the position of the objective lens 62 approaches the optical disc 200, the condensing of the laser beam 10B is performed. The position 10F also approaches the optical disc 200.
[0039]
The determination of which position the condensing position 10F of the laser beam 10B is is performed based on the detection signal in the light receiving element 56. More specifically, as shown in FIG. 12, the light receiving element 56 is divided into four areas 56a, 56b, 56c, and 56d, and a signal indicating the signal level received in each area is RF. The signal is output to the servo circuit 13 via the amplifier 12. When the condensing position 10B is on the recording layer 202 (groove 202a), the image of the reflected light detected by the light receiving element 56 is a circle (FIG. 12A), while the condensing position 10B. Is displaced from the groove 202a, the image of the reflected light detected by the light receiving element 56 becomes a vertical ellipse or a horizontal ellipse (FIGS. 12B and 12C).
[0040]
From the above, when the received light signals in the four areas 56a, 56b, 56c and 56d are Sa, Sb, Sc and Sd, respectively, the signal Sb and the signal Sd are subtracted from the sum of the signal Sa and the signal Sc. (Signal S in FIG. 12 _FE It is possible to determine whether or not the condensing position 10F of the laser beam 10B is on the groove 202a.
This focus error signal S _FE Is calculated in the servo circuit 13, the control unit 16 outputs the focus error signal S _FE By detecting this level value, it is determined whether or not the condensing position 10F of the laser beam 10B is on the recording layer 202 (groove 202a). That is, the control unit 16 generates the focus error signal S. _FE When the light level becomes 0, it is determined that the condensing position 10F is on the groove 202a, and the focus error signal S _FE When the level does not become 0, it is determined that the condensing position 10F is not in the groove 202a.
[0041]
When the condensing position 10F is located far away from the groove 202a, light is hardly reflected from the optical disc 200, so that the levels of the received light signals Sa, Sb, Sc, Sd become almost zero, and as a result, the focus error signal S _FE Becomes zero level. In order to distinguish from such a case, a signal S obtained by adding all the received light signals in the four areas 56a, 56b, 56c, and 56d. _SUM And the focus error signal S is higher than a predetermined level. _FE It is preferable to determine that the light converging position 10F is on the groove 202a when the level becomes zero.
[0042]
Focus error signal S when the objective lens 62 is moved in the direction approaching the optical disc 200 _FE And signal S _SUM Is illustrated in FIG. Signal S _SUM The level of becomes higher as the condensing position 10F of the laser beam 10B approaches the groove 202a, and takes a peak when the condensing position 10F is on the groove 202a. On the other hand, the focus error signal S _FE When the condensing position 10F of the laser beam 10B comes close to the groove 202a, the level changes in such a way as to draw a so-called S curve (see FIG. 12). Here, the center (zero level) of the S curve comes when the condensing position 10F is on the groove 202a.
[0043]
As described above, the focus error signal S _FE Is calculated in the servo circuit 13, the control unit 16 performs the focus error signal S in the servo circuit 13. _FE When the S curve is detected, the focus actuator 64 is controlled so as to stop the position movement of the objective lens 62. The focus error signal S _FE The servo circuit 13 is instructed to feedback-control the position of the objective lens 62 (the position in the optical axis direction) so that the level of the first lens is zero. Thereafter, the servo circuit 13 performs the focus error signal S. _FE The focus actuator 64 is controlled so that the level of becomes zero. For example, even if the optical disk 200 is rotated up and down due to the rotation of the optical disk 200, the servo circuit 13 drives the focus actuator 64 so as to follow the movement of the optical disk 200 to control the position of the objective lens 62. As a result, control (feedback control) is performed so that the laser beam 10B is always focused on the recording layer 202 (groove 202a).
[0044]
(Focus control during image formation)
Next, the focus control content during image formation will be described. The focus error signal S is determined from the focus control content, that is, the signals received in the four areas 56a, 56b, 56c, and 56d of the light receiving element 53. _FE Is generated, and focus control is performed based on this, as described above.
[0045]
Focus error signal S when the objective lens 62 is moved in the direction approaching the optical disc 200 _FE And signal S _SUM Is illustrated in FIG. As described above, the signal S _SUM The level of becomes higher as the condensing position 10F of the laser beam 10B approaches the groove 202a, and takes a peak when the condensing position 10F is on the groove 202a. Here, when the objective lens 62 is further moved in the direction approaching the optical disc 200, the light condensing position 10F moves away from the groove 202a, but this time approaches the discoloration layer 205, so that the signal S _SUM The level of will increase again. A second peak is obtained when the condensing position 10F is on the groove 202a.
On the other hand, the focus error signal S _FE When the condensing position 10F comes near the groove 202a, it changes so as to draw an S curve (first S curve), but then when the condensing position 10F comes near the discoloration layer 205 Similarly, it changes so as to draw an S curve (second S curve). Here, the center (zero level) of the S curve corresponds to the case where the condensing position 10F is on the groove 202a, or the case where the condensing position 10F is in the discoloration layer 205.
[0046]
From the above, the control unit 16 controls the position of the objective lens 62 so as to be close to the optical disc 200, and the focus error signal S in the servo circuit 13. _FE Even when the S curve (first S curve) is detected, the focus actuator 64 is not controlled to stop the position movement of the objective lens 62. Then, the position of the objective lens 62 is controlled so as to be closer to the optical disc 200.
Thereafter, the control unit 16 causes the focus error signal S in the servo circuit 13. _FE When the S curve (second S curve) is detected, the focus actuator 64 is controlled to stop the position movement of the objective lens 62. At this point, the focus error signal S _FE The servo circuit 13 is instructed to control the position of the objective lens 62 (position in the direction of the optical axis) so that the level of the lens is zero. As a result, the servo circuit 13 causes the focus error signal S _FE The focus actuator 64 is controlled so that the level of the laser beam becomes zero, and control (feedback control) is performed so that the laser beam 10B is always focused on the discoloration layer 205.
[0047]
The discoloration layer 205 is not formed with a spiral groove like the recording layer 202. For this reason, the spot diameter of the laser light irradiated onto the color changing layer 205 may be controlled to be larger than the spot diameter in the recording layer 202. That is, the focus position 10F of the laser beam 10B may be deliberately controlled so as to be slightly shifted rather than on the color changing layer 205, and the spot diameter of the laser light irradiated onto the color changing layer 205 may be increased.
In this case, the control unit 16 sends the focus error signal S _FE The servo circuit 13 may be instructed to feedback-control the position of the objective lens 62 so that the level of is a value other than 0. In the present embodiment, the control unit 16 and the servo circuit 13 constitute beam spot control means.
[0048]
The purpose of increasing the spot diameter of the laser light applied to the color changing layer 205 in this way is to shorten the processing time for forming a visible image. That is, as schematically shown in FIG. 15, when the beam spot diameter BS of the laser light irradiated onto the optical disc 200 (discoloration layer 205) is increased, image formation is performed during one rotation of the optical disc 200 as compared with a case where the beam spot diameter BS is small. Since the area that can be formed is wider, the time for forming a visible image on the entire optical disc 200 is shortened.
Here, if an excessively large spot diameter is irradiated, there arises a problem that the resolution of the formed visible image is deteriorated. For this reason, it is preferable to make it several times larger than the spot diameter of the laser beam irradiated to the recording layer 202 during information recording.
[0049]
(Operation related to image formation)
When focus control is executed as described above, the control unit 16 actually executes processing for forming a visible image on the discoloration layer 205 of the optical disc 200. Specifically, a laser beam of a predetermined level is irradiated to the discoloration layer 205 of the optical disk 200 that is rotationally driven to form a visible image.
However, the discoloration layer 205 does not have a role as a guide unlike the groove 202a in the recording layer 202, and thus the discoloration layer 205 is recorded as described below.
[0050]
FIG. 16 is a flowchart showing the control content of the control unit 16 when a visible image is formed on the color changing layer 205.
First, the control unit 16 transfers the image data supplied from the host PC 110 via the buffer memory 36 to the FIFO memory 34 (step Sa1). 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 200 rotated by the spindle motor 11 has passed the laser light irradiation position of the optical pickup 10. Is determined (step Sa2).
[0051]
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. 17 and 18.
As shown in FIG. 17, the frequency generator 21 outputs a predetermined number (eight in FIG. 17) of FG pulses while the spindle motor 11 rotates once, that is, while the optical disk 200 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 pulse after the end of the minute. By generating such a reference position detection pulse, it is detected that the time when the pulse is generated is the timing at which the laser light irradiation position of the optical pickup 10 passes the reference position of the optical disc 200.
That is, as shown in FIG. 18, when it is assumed that the laser light irradiation position of the optical pickup 10 at the timing when the first reference position detection pulse is generated is the position indicated by the thick line in the figure, the reference position detection generated after one rotation is performed. When the working pulse is generated, the laser beam irradiation position of the optical pickup 10 is again at the position indicated by the thick line in the figure. As described above, 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 every time the optical disk 200 rotates as described above. It is possible to detect that the irradiation position of the laser beam has passed the reference position of the optical disc 200 based on the reference position detection pulse signal. Note that the alternate long and short dash line shown in FIG. 18 is an example of the movement locus of the irradiation position of the laser light from the generation of a certain reference position detection pulse to the generation of the next reference position detection pulse.
[0052]
After receiving the image formation instruction from the host PC 110, when it is detected that the reference position of the optical disc 200 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 Sa3), it is determined whether or not R is an odd number (step Sa4).
[0053]
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 Sa4. Is determined. If it is determined that R is an odd number, the control unit 16 performs control for forming a visible image by irradiating the discoloration layer 205 of the optical disc 200 with laser light from the optical pickup 10 (step Sa5). 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. With this control, every time a clock pulse is supplied from the PLL circuit 33, the FIFO memory 34 outputs information indicating the gradation of one coordinate to the drive pulse generation unit 35, and the drive pulse generation unit 35 includes the information. A drive pulse having a pulse width according to the indicated gradation is generated and output to the laser driver 19. As a result, the optical pickup 10 irradiates the discoloration layer 205 of the optical disc 200 with the laser light at the light level for a time corresponding to the gradation of each coordinate, and the irradiation region changes color, so that the visible light as shown in FIG. An image can be formed.
[0054]
As schematically shown in FIG. 19, since the optical disc 200 is rotated by the spindle motor 11, the irradiation position of the laser light 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 up to 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, different areas according to the different gradation levels for each region C. Can be discolored. In this way, a visible image corresponding to the image data is formed on the color changing layer 205 of the optical disc 200.
[0055]
After performing a series of controls for forming a visible image as described above, the processing of the control unit 16 returns to step Sa1 and transfers the image data supplied from the buffer memory 36 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 200, and when it is detected that the reference position has 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 Sa6). 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. That is, after the control unit 16 forms a visible image by irradiating the color changing layer 205 of the optical disc 200 with a light level laser beam, the color changing layer 205 is changed in color during the next rotation of the optical disc 200. Control is performed so that laser light irradiation is not performed.
[0056]
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 Sa7). 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.
[0057]
Here, the predetermined amount by which the optical pickup 10 is moved in the radial direction of the optical disc 200 is appropriately determined according to the beam spot diameter BS (see FIG. 15) irradiated from the optical pickup 10 as described above. When a visible image is formed, it is preferable to irradiate the laser beam on the discoloration layer 205 of the optical disc 200 with almost no gap. Therefore, the amount of movement (unit movement amount) of the optical pickup 10 is determined as the beam spot diameter. The length may be almost the same as the BS. In addition, when the thermal sensitivity of the color changing layer 205 is high, a wide area is discolored (colored) than the area irradiated with the laser light, and when the thermal sensitivity of the color changing layer 205 is low, the laser light is irradiated. It is also assumed that only a narrower area than the other area is discolored (colored). In such a case, the unit movement amount may be determined in consideration of the width of the area to be discolored so that adjacent discoloration areas do not overlap.
The control unit 16 drives the stepping motor 30 by controlling the motor controller 32 so as to move the optical pickup 10 in the radial direction by the unit movement amount thus determined. The stepping motor 30 in recent years can control the amount of movement in units of 10 μm by using the μ step technology, and the optical pickup 10 is moved in the radial direction at the μm level using the stepping motor 30. It is fully feasible.
[0058]
The control unit 16 adjusts the light level of the laser light in conjunction with the radial movement control of the optical pickup 10.
In other words, since the CAV method is employed in the present embodiment, the linear velocity becomes larger as the optical pickup 10 is moved to the outer peripheral side of the optical disc 200. In general, when the linear velocity increases, it is necessary to irradiate a laser beam with a higher level. Therefore, the controller 16 increases the light level by a predetermined amount each time the position of the optical pickup 10 is moved to the outer periphery of the disk. The power control circuit 20 is controlled. It should be noted that how much level is increased may be obtained in advance by performing a recording experiment or a simulation experiment.
[0059]
After the control for moving the optical pickup 10 in the disk radial direction and the control for changing the target value of the light level in this way, the control unit 16 generates unprocessed image data, that is, drive pulses for visible image formation. It is determined whether or not there is image data that has not been supplied to the unit 35. If there is no image data, the process is terminated (step Sa9).
[0060]
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 Sa1 again to continue processing for visible image formation. As described above, the control unit 16 performs recording for forming a visible image from the inner periphery to the outer periphery of the optical disc 200.
As described above, the optical pickup performs recording for visible image formation during the first round (when R is an odd number), and does not perform image formation during the next round (when R is an even number). The position movement control and the light level adjustment of 10 are performed because the laser beam irradiation position is stabilized and the light level is reliably adjusted, and then recording for visible image formation is performed. This is for ensuring the formation of a visible image.
[0061]
The above is the content of the main operation of the optical disc recording apparatus 100 according to the present embodiment. Thus, according to the optical disc recording apparatus 100, not only the original information can be recorded on the optical disc 200, but also characters and the like can be formed on the optical disc 200 as a visible image. Once the user sets the optical disc 200 with the recording surface (see FIG. 1) facing the optical pickup 10 once in the optical disc recording apparatus 100, information is recorded on the recording layer 202 of the optical disc 200 as in the conventional apparatus. In addition, a visible image can be formed on the color changing layer 205.
For this reason, the user does not need to prepare a dedicated printer device, and needs to perform a complicated operation such as taking out the recorded optical disc 200 from the device and attaching a label sheet, or turning the removed disc over and setting it again. Nor.
[0062]
C. Modified example
In addition, this invention is not limited to embodiment mentioned above, Various deformation | transformation which is illustrated below is possible.
[0063]
(Modification 1)
For the optical disc 200 in which the recording layer 202 and the color changing layer 205 are made of the same material, a visible image can also be formed on the recording layer 202.
As described above, since the groove is formed in the recording layer 202 in a spiral shape, data for forming a visible image may be recorded along the groove in the same manner as information recording.
Alternatively, as in the case of forming a visible image on the discoloration layer 205, the beam spot diameter of the laser light applied to the recording layer 202 is greatly adjusted to form a visible image regardless of the position where the groove is formed. Data recording may be performed. That is, since the interval at which the grooves are formed (so-called track pitch) is a narrow value of about several μm, there is no problem that the resolution of the formed visible image is lowered without performing recording along the grooves. . Further, since grooves are formed on the surface of the recording layer 202, strictly speaking, there are surface irregularities (see FIG. 1), but the depth of the grooves is a narrow value of about several μm. In forming a visible image, the recording layer 202 can be handled as a plane.
In any case, if the technique related to the present invention is used, a visible image can be formed on the optical disc 200 without preparing any dedicated device. According to this modification, not only the discoloration layer 205 but also the discoloration layer 205 can be formed. A visible image can also be formed on the recording layer 202. That is, in this modification, an image (visible image) that can be seen from the recording surface side (see FIG. 1) of the optical disc 200 can be formed on the recording layer 202, and can be seen from the label surface side (see FIG. 1) of the optical disc 200. An image (visible image) can be formed on the color changing layer 205, and visible images can be formed on both surfaces of the so-called optical disc 200.
[0064]
Note that when a visible image is formed, part of the laser light incident on the recording layer 202 is transmitted through the semi-transmissive reflective layer 203 and is also irradiated on the discoloration layer 205. Therefore, in consideration of the influence on the color changing layer 205, (1) the recording layer 202 (groove 202a) is irradiated with sufficient laser light that can change the color development, and (2) the color changing layer. It is only necessary not to irradiate the laser beam having such a high level as to change the color to 205, and to adjust the output level of the laser beam so as to satisfy the above two conditions.
[0065]
(Modification 2)
Further, when a visible image is formed on the recording layer 202 of the optical disc 200, it is of course 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 200 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.
[0066]
(Modification 3)
In the above-described embodiment, it is assumed that when a visible image is formed on the optical disc 200, data to be recorded is supplied from the external device (host PC 110) to the optical disc recording device 100. It may be configured to be stored in advance in the ROM of the unit 16 or the like. For example, in order to form numbers 0 to 9 on the optical disc 200 as a visible image, data to be recorded is stored in the discoloration layer 205, and recording data related to the number designated by the user is read from the memory. A visible image may be formed by recording on the optical disc 200.
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.
[0067]
(Modification 4)
It is assumed that the characteristics of the transflective layer 203 and the color changing layer 205 are different depending on the type of the optical disc 200. That is, if the transmissivity (or reflectivity) of the transflective layer 203 is different, even if the same level of laser light is emitted from the optical pickup 10, the level of the laser light applied to the color changing layer 205 is different. Or, if the thermal sensitivity of the color changing layer 205 is different, even if the laser beam of the same level is irradiated to the color changing layer 205, the color change is not necessarily performed. In preparation for such a case, recording experiments and simulations are performed on various types of optical discs 200 to determine in advance how much laser light should be emitted when forming an image, and the obtained values are controlled. It may be stored in the ROM of the unit 16. In this case, it is stored in association with disk ID information for identifying each optical disk 200, and when actually forming an image, the disk ID information of the set optical disk 200 is discriminated before the emitted laser beam. The level may be adjusted.
[0068]
(Modification 5)
In the above-described embodiment, it is assumed that the optical disc 200 is a so-called two-layer disc having the recording layer 202 and the color changing layer 205, but an optical disc having a multilayer structure may be used. For example, even if the optical disk has two or more color changing layers 205 in addition to the recording layer 202, the laser beam 10B can be focused on each color changing layer 205 by applying the present invention. A desired visible image can be formed on the desired color changing layer 205. For example, if the color changing layer 205 is made of a material having transparency, a character is formed as a visible image for a certain color changing layer 205, and a background image is formed as a visible image for a certain color changing layer 205. The character and the background image can be identified together when viewed as the entire optical disc 200.
In addition, when the color changing layer 205 is made different in color (for example, blue and red) and the same visible image is formed on each color changing layer 205 and viewed as the entire optical disc 200, so-called 2 is obtained. You may make it show the effect of color printing.
[0069]
【The invention's effect】
As described above, according to the present invention, it is possible not only to record information on an optical disc but also to form a visible image such as characters indicating the recorded contents without preparing a dedicated device.
[Brief description of the drawings]
FIG. 1 is a side sectional view showing a schematic configuration of an optical disc 200 capable of forming a visible image by an optical disc recording apparatus 100 according to an embodiment of the present invention.
FIG. 2 is a diagram for explaining the configuration of an optical disc 200. FIG.
FIG. 3 is a diagram for explaining the configuration of an optical disc 200. FIG.
FIG. 4 is a block diagram showing a configuration of an optical disc recording apparatus 100 according to an embodiment of the present invention.
5 is a diagram showing a configuration of an optical pickup 10 that is a component of the optical disc recording apparatus 100. FIG.
FIG. 6 is a diagram for explaining the contents when the optical disc recording apparatus 100 forms a visible image on the optical disc 200 (discolored layer 205).
FIG. 7 is a diagram for explaining a method of controlling laser light when forming a visible image.
FIG. 8 is a diagram for explaining a method of controlling laser light when forming a visible image.
FIG. 9 is a diagram for explaining the level of light reflected when an optical disc 200 is irradiated with laser light.
FIG. 10 is a diagram for explaining the operation of the frequency generator 21;
11 is a diagram for explaining an outline of focus control in the optical disc recording apparatus 100. FIG.
12 is a diagram for explaining an outline of focus control in the optical disc recording apparatus 100. FIG.
FIG. 13 is a diagram for explaining the content of focus control during information recording.
FIG. 14 is a diagram for explaining the content of focus control during visible image formation.
FIG. 15 is a diagram for explaining a spot diameter of a laser beam irradiated to a color changing layer 205 when a visible image is formed.
FIG. 16 is a flowchart showing the control content of the control unit 16 when a visible image is formed on the color changing layer 205;
FIG. 17 is a diagram for explaining an operation when a visible image is formed.
FIG. 18 is a diagram for explaining an operation when a visible image is formed.
FIG. 19 is a diagram for explaining an operation when a visible image is formed.
[Explanation of symbols]
10 ... Optical pickup, 11 ... Spindle motor,
12 ... RF amplifier, 13 ... servo circuit, 16 ... control unit,
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 generator,
36 …… Buffer memory,
53 …… Laser diode, 53a …… Front monitor diode,
56... Light receiving element,
64 …… Focus actuator, 65 …… Tracking actuator,
100: optical disk recording device,
200: optical disc, 201: protective layer, 202: recording layer,
203... Transflective layer, 204... Protective layer, 205... Color changing layer, 206... Reflective layer, 207.

Claims (4)

Rotation for rotating an optical disk on which a recording layer for recording information on one side, a color changing layer whose color changes by heat on the other side, and a translucent material formed between the recording layer and the color changing layer, respectively Means,
An optical pickup that irradiates the optical disk rotated by the rotating means with laser light from the one surface and is movable in a substantially radial direction of the optical disk;
Means for adjusting a level of laser light emitted from the optical pickup when forming a visible image on the discoloration layer, and based on image data representing the visible image to be formed, the recording layer of the optical disc and The first intensity corresponding to the transmissivity of the semi-transmissive material that hardly changes the color changing layer, or the transmission of the semi-transmissive material that changes the color of the color changing layer while hardly changing the recording layer. An optical disk recording apparatus comprising: laser light level control means for adjusting a level of laser light emitted from the optical pickup so as to have one of the second intensities according to the rate. The optical disk recording apparatus according to claim 1,
The optical disk recording apparatus, wherein the laser light level control means controls a time during which the second intensity laser light is emitted according to a gradation level of a visible image indicated in the image data. The optical disk recording apparatus according to claim 1,
There is a focus actuator that adjusts the position in the optical axis direction of the objective lens that condenses the laser beam emitted from the optical pickup to the optical disc, and determines the spot diameter of the laser light that irradiates the discoloration layer. And
The focus actuator is controlled so that the spot diameter of the laser beam applied to the discoloration layer when forming a visible image is larger than the spot diameter of the laser beam applied to the recording layer when recording information. An optical disc recording apparatus comprising: a focus control unit. The optical disk recording apparatus according to claim 1,
An optical disc recording apparatus characterized in that, when the color of a recording layer in the optical disc changes due to heat, a visible image is also formed on the recording layer.

Images