JP2004030800A - Optical disk recording device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical disk recording device which forms an image having high visibility on a recording surface of an optical disk. <P>SOLUTION: A laser power correction value to be a parameter for information recording used when information recording is performed, and optimal laser power to be a parameter for image formation used when image formation is performed, are combined and recorded in each kind of organic dye which is used for a recording layer of an optical disk in the media data base 1120. In this constitution, when information recording is performed, information recording is performed corresponding to the parameter for information recording, and when image formation is performed, image formation is performed corresponding to the parameter for image formation. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an optical disc recording apparatus for recording information on an optical disc such as a compact disc-recordable (CD-R) or a compact disc-rewritable (CD-RW), and more particularly, to forming an image on a recording surface of an optical disc. About technology.
[0002]
[Prior art]
2. Description of the Related Art In recent years, personal computer systems and the like generally include an optical disk recording device that reads and records information on recordable optical disks such as CD-Rs and CD-RWs. The case where an optical disk recording apparatus records information on an optical disk will be briefly described using a CD-R as an example. A recording layer (dye layer) that changes color by irradiating a laser beam is provided on a recording surface of the optical disk. The optical disk recording apparatus adjusts laser power according to information (bits) to be recorded, and records information by changing light reflectance by thermal discoloration of the recording layer. Further, in the conventional optical disk recording apparatus, when information is recorded, the laser power is adjusted (corrected) according to the material of the recording layer and the like, whereby the laser power is adjusted to the material of the optical disk. Information recording is performed with laser power.
[0003]
By the way, recently, not only information is recorded on a recording surface of an optical disc, but also an image such as a character or an image (an image that can be visually recognized by a user) is applied to the recording surface by applying that the recording layer is thermally discolored by laser beam irradiation. It is also under consideration to form it.
[0004]
[Problems to be solved by the invention]
However, as a parameter value such as a laser power used when forming an image, a parameter value used at the time of information recording, that is, a parameter value optimal for information recording is used, but the parameter value is formed using this parameter value. The image may be difficult for the user to see.
[0005]
The present invention has been made in view of the above circumstances, and has as its object to provide an optical disc recording apparatus capable of forming a highly visible image on a recording surface of an optical disc.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides an optical pickup that irradiates a laser beam onto a recording surface of an optical disc to record information, form an image, and read information recorded on the recording surface. An optical disc recording apparatus, wherein storage means for storing information recording parameters used for information recording and image forming parameters used for image formation in combination for each piece of identification information for identifying an optical disc, When recording information after controlling the optical pickup to read the identification information of the optical disc recorded in advance on the recording surface of the optical disc, the information recording parameter corresponding to the read identification information is stored in the storage means. While controlling the information to be recorded on the recording surface in accordance with the information recording parameter, while forming an image. The imaging parameters corresponding to the identification information read by reading from said storage means, to provide an optical disc recording apparatus and control means for controlling so that an image is formed in accordance with the imaging parameters.
[0007]
According to this configuration, at the time of recording information or forming an image on the recording surface, an information recording parameter or an image forming parameter corresponding to the identification information of the optical disc is read, and the information is read according to the read parameter. Recording or image formation is performed. Therefore, information recording and image formation corresponding to each optical disc are performed. In particular, when the material of the recording surface is included as the identification information, an image is formed with image forming parameters corresponding to the material of the recording surface of the optical disc. Prevention of difficulty in visual recognition due to the difference is prevented, and an image with high visibility can be formed.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, an optical disk recording device that records information on a CD-R will be exemplified. Note that information recording and image formation are performed by a method of driving the optical disk to rotate so that the rotation speed becomes constant, that is, a CAV (Constant Angular Velocity) method.
[0009]
FIG. 1 is a block diagram showing a functional configuration of an optical disc recording device 10 according to the present embodiment. 1, the control unit 112 includes a CPU (Central Processing Unit), a ROM (Read Only Memory) 112a, a RAM (Random Access Memory), and the like. The ROM 112a stores programs for a recording process on the recording surface of the optical disc 20, an image forming process, and an information reading process, and the control unit 112 controls each unit of the optical disc recording device 10 according to the program. The ROM 112a stores various data, which is one of the features of the present invention, in addition to the program. The data stored in the ROM 112a will be described later in detail.
[0010]
The spindle motor 100 drives the optical disc 20 to rotate. The frequency generator 102 outputs an FG pulse signal having a frequency corresponding to the spindle rotation speed (the number of rotations per unit time) to the servo circuit 108 using a back electromotive current obtained from a motor driver of the spindle motor 100. The servo circuit 108 performs feedback control of the spindle motor 100 so that the spindle rotation speed indicated by the FG pulse signal is substantially equal to the angular speed indicated by the instruction signal from the control unit 112.
[0011]
The optical pickup 104 is a unit that irradiates the optical disc 20 with laser light, and its schematic configuration is shown in FIG. As shown in this figure, the optical pickup 104 roughly includes a light emitting unit 1040, a light receiving unit 1042, an optical system 1044, and an optical system driving unit 1046. The light emitting unit 1040 includes an LD (Laser Diode) and emits a laser beam toward the optical system 1044. The optical system 1044 guides the laser light from the light emitting unit 1040 onto the surface of the optical disc 20, and has a large number of optical elements. That is, a diffraction grating 1044a, a polarizing beam splitter 1044b, a collimator lens 1044c, a 波長 wavelength plate 1044d, and an objective lens 1044e. The laser light emitted from the light emitting unit 1040 passes through the optical elements 1044a to 1044e in this order, and is condensed on the recording surface of the optical disc 20, and pits are formed in the converged spot during information recording.
[0012]
The pit formation on the recording surface of the optical disc 20 will be specifically described with reference to FIG. FIG. 3 is a diagram showing a cross-sectional structure of the optical disc 20. As shown in this figure, the optical disc 20 has a structure in which a protective layer 202, a reflective layer 204, a recording layer 206, and a protective layer 208 are laminated in this order from the label surface above the drawing to the recording surface below the drawing. I have. The protective layer 208 is formed from a synthetic resin material such as polycarbonate, and the protective layer 208 has a pre-groove 202a serving as a guide groove for laser light. The recording layer 206 is a layer containing, for example, an organic dye such as a cyanine-based, phthalocyanine-based, or azo-based dye. When a laser beam having a predetermined intensity or more is irradiated per unit area, the recording layer 206 is irradiated by heat generated during laser beam irradiation. Some organic dyes decompose. At the time of information recording, the recording layer 206 is irradiated with laser light having a power such that the intensity per unit area reaches a predetermined value, and pits are formed by decomposition of the organic dye. In addition, in the present embodiment, by applying this, a large number of thermally discolored portions (dots) are formed on the recording surface of the optical disk 20 so that the recording surface can be printed on the recording surface. A visible image (an image that can be visually recognized by a human) as shown in FIG.
[0013]
In FIG. 3, a reflection layer 204 is a layer for reflecting a laser beam emitted from the optical pickup 104, and is formed of a metal film such as aluminum. The protective layer 208 is a layer for preventing the reflective layer 204 from being damaged or being chemically changed by contacting the reflective layer 204 with the outside air, and is formed of a material that transmits laser light. . In this configuration, the laser light emitted from the optical pickup 104 is reflected by the reflective layer 204 according to the presence or absence of a pit, and the reflected light enters the optical system 1044 as return light.
[0014]
As shown in FIG. 2, the optical system 1044 further includes a cylindrical lens 1044 f that condenses the light reflected by the polarization beam splitter 1044 e on the light receiving surface of the light receiving unit 1042, and is reflected on the surface of the optical disc 20. The laser light (return light) is guided to the light receiving unit 1042 through the objective lens 1044e, the ４ wavelength plate 1044d, the collimator lens 1044c, the polarization beam splitter 1044b, and the cylindrical lens 1044f in this order. The light receiving unit 1042 outputs a light receiving signal corresponding to the amount of received light to an RF (Radio Frequency) amplifier 106 shown in FIG.
[0015]
The RF amplifier 106 amplifies the light receiving signal from the optical pickup 104 and outputs the signal as an RF signal to each of the servo circuit 108, the decoder 110, the ATIP (Absolute Time In Pregroove) detecting circuit 109, and the β value detecting circuit 111. When the optical disc 20 is reproduced, the RF signal is a signal modulated by EFM (Eight to Fourteen Modulation), and the decoder 110 performs EFM demodulation on the received RF signal to generate reproduction data, Output to 112. Thereby, the information recorded on the optical disc 20 is reproduced.
[0016]
The ATIP detection circuit 109 extracts a wobble signal component from the RF signal, demodulates ATIP information included in the wobble signal component, and outputs the demodulated ATIP information to the control unit 112. More specifically, as shown in FIG. 4, on the recording surface of the optical disc 20, the above-described pre-group 202a is spirally formed. The pre-group 202a meanders (wobbles) according to a signal obtained by FM-modulating the ATIP information, and the ATIP information can be obtained from the detection result of the wobble. The ATIP information includes address information (time information) at each point on the optical disc 20 along the pre-group 202a. Accordingly, by receiving the ATIP information demodulated by the ATIP detection circuit 109, the control unit 112 can specify which part (address) of the optical disc 20 is irradiated with the laser beam from the optical pickup 104. The ATIP information includes media information (media ID) as identification information for identifying the optical disc 20. The media information includes information unique to each optical disc 20 such as the name of the manufacturer of the optical disc 20 and the type of organic dye used for the recording layer 206 of the optical disc 20. Manufacturers and types of organic dyes can be identified from the information.
[0017]
The β value detection circuit 111 obtains a β value when reproducing a pit formed on the recording surface of the optical disc 20 and outputs the β value to the control unit 112. The β value indicates whether pits having a shape necessary for obtaining a reproduced signal of sufficient quality are formed, and the peak level (sign is +) of the EFM signal waveform obtained by reproducing the pits is represented by a. , And the bottom level (the sign is −) is b (see FIG. 6), it is obtained by (a + b) / (ab).
[0018]
The servo circuit 108 generates a focus signal and a tracking signal in accordance with the RF signal in order to perform tracking control and focus control in addition to the control of the spindle motor 100 described above, and the optical system driving unit 1046 of the optical pickup 104. Output to The optical system driving unit 1046 (see FIG. 2) moves the objective lens 1044e in accordance with a signal from the servo circuit 108, and includes two actuators that hold the objective lens 1044e. That is, a focus actuator 1046a and a tracking actuator 1046b. The focus actuator 1046a moves the objective lens 1044e in the optical axis direction according to the focus signal from the servo circuit 108, while the tracking actuator 1046b moves the objective lens 1044e in the radial direction of the optical disc 20 according to the tracking signal.
[0019]
Here, the focus signal is a signal for instructing the moving distance of the objective lens 1044e so that the laser beam from the optical pickup 104 is focused on a pit formed on the recording surface of the optical disc 20. The tracking signal is a signal for instructing the moving distance of the objective lens 1044e in the radial direction of the optical disc 20 so that the laser light is irradiated along the pre-group 202a formed on the recording surface of the optical disc 20. The servo circuit 108 performs the above-described focus control and tracking control by generating the focus signal and the tracking signal according to the RF signal.
[0020]
The optical pickup 104 is provided with a front monitor diode (not shown) in addition to the above-described components. The front monitor diode generates a current having a magnitude corresponding to the amount of emitted light while the light emitting unit 1040 emits laser light, and this current is transmitted from the optical pickup 104 to the laser power control circuit (FIG. 1). LPC) 124. The laser power control circuit 124 generates a power instruction signal that defines the power of the laser light emitted from the optical pickup 104 from the current value from the front monitor diode and the instruction signal from the control unit 112 and outputs the signal to the laser driver 120. I do. More specifically, laser power control circuit 124 controls laser driver 120 such that the laser power indicated by the current value from the front monitor diode substantially matches the laser power indicated by the instruction signal from control unit 112. For generating a power instruction signal.
[0021]
The buffer memory 114 is a memory for temporarily storing various data from a personal computer (hereinafter, referred to as “host PC”) 30 which is an external device connected to the optical disk recording device 10 via a signal cable. The stored data includes image data indicating an image to be formed on the recording surface of the optical disc 20, recording data indicating information to be recorded, and the like. The buffer memory 114 outputs the image data to the control unit 112, Further, the recording data is output to the encoder 116. On the other hand, an application program for transmitting recording data and image data to the optical disk recording device 10 and instructing the optical disk recording device 10 to form an image on the optical disk 20 and record information is installed in the host PC 30. Have been. By causing the host PC 30 to execute the application program, the user can instruct the optical disc recording apparatus 10 to form an image or record information.
[0022]
The encoder 116 performs EFM modulation on the recording data and outputs the recording data to the strategy circuit 118. The strategy circuit 118 performs a time axis correction process on the EFM signal and outputs the result to the laser driver 120. The laser driver 120 generates a laser drive signal according to a signal from the strategy circuit 118 and a signal from a drive pulse generation unit 122 and a laser power control circuit (LPC) 124, which will be described later. Output to In this configuration, information is recorded by the light emitting unit 1040 irradiating the recording surface of the optical disc 20 with laser light defined by the laser drive signal.
[0023]
Here, the image data used in the host PC 30 is generally in a bitmap format in which an image is represented by a set of dots (pixels) whose gradation (shading) is specified. Therefore, when receiving the bitmap image data from the buffer memory 114, the control unit 112 associates each dot constituting the image with an address on the optical disc 20, and determines the gradation assigned to the dot. Make an address correspondence. Thus, the address on the optical disc 20 and the gradation of the dot to be formed at this address are determined. When actually forming each dot of the image on the optical disc 20, the control unit 112 receives the address information included in the ATIP information supplied from the ATIP detection circuit 109, and stores the address of the dot to be formed at this address. The tone is specified, and an instruction signal is output to the drive pulse generator 122 and the laser power control circuit 124 according to the tone. In the present embodiment, for the sake of simplicity, the image to be formed is a so-called black-and-white image, that is, an image having two gradations. Is irradiated only with the laser beam.
[0024]
The drive pulse generation unit 122 generates a drive pulse for controlling the irradiation timing and irradiation time of the laser light in accordance with the instruction signal from the control unit 112, and outputs the drive pulse to the laser driver 120. In the present embodiment, since the optical disc 20 is rotated by the CAV method, the rotational linear velocity increases toward the outer peripheral side of the optical disc 20. Therefore, when pits are formed by irradiating a laser beam for a certain period of time, the pit length of the pit formed on the outer peripheral side of the optical disc 20 becomes longer than that on the inner peripheral side. When the optical disk on which such pits are formed is rotated by another driving method such as the CLV method, information cannot be reproduced. Therefore, the drive pulse generation unit 122 generates a drive pulse for instructing a laser irradiation time and outputs the drive pulse to the laser driver 120 so that a pit having a length to be formed is formed.
[0025]
The stepping motor 126 is a motor for moving the optical pickup 104 in the radial direction of the optical disc 20. The motor driver 128 rotationally drives the stepping motor 126 by an amount corresponding to the pulse signal supplied from the motor controller 130, and moves the stepping motor 126 in the radial direction of the optical disc 20. The motor controller 130 generates a pulse signal according to the movement amount and the movement direction according to the movement start instruction including the movement direction and the movement amount of the optical pickup 104 in the radial direction instructed by the control unit 112 and outputs the pulse signal to the motor driver 128. I do. As described above, the stepping motor 126 moves the optical pickup 104 in the radial direction of the optical disc 20 (so-called feed feed), and the spindle motor 100 rotates the optical disc 20 by driving the laser of the optical pickup 104. The light irradiation position can be moved to various positions on the optical disc 20.
[0026]
The ROM 112a included in the control unit 112 stores a media database 1120 as shown in FIG. As shown in this figure, the media database 1120 contains, for each type of organic dye that can be used for the recording layer 206 of the optical disc 20, a laser power correction value, which is an information recording parameter used at the time of information recording, and an image forming parameter. The optimum laser power, which is an image forming parameter sometimes used, is recorded as a set. Here, the laser power correction value is a value for correcting the laser power used for recording information on the optical disc 20 for each type of organic dye. This correction value will be described more specifically. Prior to actual information recording, the optical disc recording apparatus 10 of the present embodiment performs OPC (Optimum Power Control) for determining an optimal laser power for information recording. In the innermost peripheral area of the optical disc 20, a PCA area (Power Calibration Area: power calibration area) is provided, and in the case of OPC, test recording is performed in this PCA area.
[0027]
In this test recording, the optical disc recording apparatus 10 formed pits each time the laser power was changed in a stepwise manner while maintaining the rotational linear velocity of the optical disc 20 constant (for example, 1 × speed), and reproduced these pits. The β value at that time is obtained for each pit. As shown in FIG. 7, there is a relationship between the β value and the jitter contained in the reproduced signal, where the jitter is optimal near the β value = βa. Therefore, if the obtained β value is β value ≒ βa when the pit is reproduced, a pit having a sufficient shape is formed. Therefore, the optical disc recording apparatus 10 obtains a laser power having a value of βa from the β value of each pit formed by changing the laser power in a stepwise manner, and determines this laser power as the optimum linear velocity at the time of test recording. Determine the laser power.
[0028]
Further, in the present embodiment, since the CAV method is used, the linear velocities of the inner circumference and the outer circumference of the optical disc 20 are different. Therefore, the optical disk recording apparatus 10 executes the above-described test recording while changing the linear velocity of the optical disk 20 (for example, 2 × speed) in order to determine the optimum laser power at another linear velocity. Then, the optical disc recording apparatus 10 obtains the relationship between the linear velocity of each double speed and the optimum laser power as shown in FIG. As described above, in the OPC, test recording is performed at a relatively low linear velocity such as, for example, 1 × speed (V1 in the figure) or 2 × speed (V2 in the figure). The optimum laser power is determined from the laser power characteristics shown in FIG.
[0029]
However, a deviation may occur between the laser power characteristic obtained by the above-described OPC and the actual ideal laser power characteristic. Therefore, in the present embodiment, a correction value for correcting the laser power characteristic obtained by the OPC, that is, a correction value of the laser power is stored in the mediator database 1120 for each type of organic dye that can be used in the recording layer 206 of the optical disc 20. It is memorized. The correction values include the following. For example, it is assumed that a laser power characteristic obtained by OPC is represented by a linear function as follows.
P = a × VL + b
Here, P is the laser power, VL is the rotational linear velocity of the optical disc 20, a is the slope, and b is the intercept value.
Generally, the slope a is a value that is substantially unique for each type of organic dye, but the intercept b is often different for each optical disc 20 to be recorded, even if the type of organic dye is the same. Therefore, only the slope a is recorded in the media database 1120 for each type of organic dye, and the intercept b is determined by the least square method or the like according to the result of the OPC. As a result, the laser power characteristics obtained only from the results of the OPC are corrected, and more accurate laser power characteristics can be obtained.
Depending on the type of the organic dye, the laser power characteristic may be a quadratic function. In this case, the coefficients of the second-order and first-order terms are stored in the media database 1120, and the zero-order term ( That is, the constant term) may be obtained from the result of the OPC. Further, the above-described correction values are merely examples, and the present invention is not limited to these. That is, the correction value is a value that can correct the laser power optimum for information recording obtained by OPC to an appropriate laser power according to the type of the organic dye used in the recording layer 206 of the optical disc 20. For example, the value may be a value for correcting laser power at the time of recording information in order to cope with, for example, optical disk warpage that occurs uniquely for each manufacturer.
[0030]
Next, the optimum laser power for image formation stored in the mediator database 1120 will be described. In general, if the laser power is the same, the image contrast becomes higher as the rotation speed of the optical disc 20 during image formation is reduced. This is because the laser beam irradiation increases the amount of heat generated per unit area of the optical disk 20, which sufficiently induces the decomposition of the dye in the recording layer 206 of the optical disk 20, and the reflective layer 204 may be thermally deformed. It is. However, if the rotation speed of the optical disc 20 is reduced in order to increase the image contrast, the time required to form all the dots constituting the image on the optical disc 20 becomes longer. Therefore, the laser power at the time of image formation needs to be determined in consideration of both the rotation speed of the optical disc 20 and the image contrast. Therefore, conventionally, the use of a β value for laser power control during image formation has been studied. As described above, the β value is an index for determining an optimum laser power for forming a pit having a sufficient shape for each rotation speed of the optical disc 20. By using the β value, the optimum laser power for image formation is defined for each rotation speed of the optical disc 20.
[0031]
However, when an image is formed with the optimum laser power for pit formation, that is, the optimum laser power for information recording, the image contrast does not always increase. FIG. 9 is a diagram showing the relationship between laser power and image contrast when the rotation speed (linear speed) of the optical disc 20 is constant, for each type of organic dye. In this figure, four kinds of organic dyes of cyanine type, super cyanine type, phthalocyanine type and azo type are illustrated as examples of organic dyes. Sometimes the optimum laser power is indicated by a circle. As shown in the figure, when the optimum laser power at the time of image formation and at the time of information recording are compared for each organic dye, a larger laser power is required at the time of image formation than at the time of information recording. Therefore, even if an image (dot) is formed with an optimum laser power at the time of recording information, the image contrast is lowered and visibility is deteriorated. In particular, phthalocyanine-based organic dyes have a low degree of thermal discoloration due to irradiation with laser light compared to other organic dyes, and therefore have poor color development. In some cases, the contrast of the image formed by may be too low to be visually recognized by the user.
[0032]
Therefore, in the present embodiment, the optimum laser power for image formation is not determined from the β value, but is determined as follows. That is, the optimum laser power is determined from the amount of heat generated per unit area of the recording layer 206 by the laser irradiation. More specifically, the thermal discoloration of the recording layer 206 is caused by the decomposition of the organic dye due to laser light irradiation, and the degree of this decomposition, that is, the degree of thermal discoloration, is determined by the unit area generated by the laser light irradiation. Depends on the amount of heat per unit. Therefore, it is only necessary to irradiate a laser beam having such a power as to generate an amount of heat that increases the image contrast due to thermal discoloration. Specifically, as shown in FIG. 9, the image contrast tends to be saturated as the laser power increases, common to each organic dye (the saturation point of each organic dye is indicated by a triangle). This is considered to be because when the laser light having a certain power or more is irradiated, the reflective layer 204 of the optical disc 20 is thermally deformed. The contrast does not change much. Therefore, if an image is formed with the laser power before the saturation point, the image contrast can be made as high as possible. Therefore, in the present embodiment, the laser power before the saturation point is the optimum laser power. The reason for setting the optimum laser power before the saturation point is to prevent the service life of the LD from being shortened, and any value is used as the optimum laser power as long as the value is near the saturation point. be able to.
[0033]
Further, as shown in FIG. 9, when compared at the same laser power, the azo-based organic dye has lower image contrast than other organic dyes. Therefore, when an image is formed by irradiating a laser beam of the same power to the optical disc 20 irrespective of the type of the organic dye, the optical disc 20 using the phthalocyanine-based organic dye has low image contrast, The visibility deteriorates. As described above, since the characteristics of the laser power and the image contrast are different for each type of the organic dye, in the present embodiment, the above-described optimum laser power at the time of image formation can be used for the recording layer 206. For each dye, the optimum laser power obtained in advance is determined by an experiment or the like, and the optimum laser power thus obtained is recorded in the media database 1120 for each type of organic dye. With such a configuration, an image can be formed with an optimum laser power according to the material of the recording surface of the optical disc 20, that is, the type of the organic dye of the recording layer 206, and the image contrast can be increased.
[0034]
Next, the operation of the optical disc recording device 10 according to the present embodiment will be described. FIG. 10 is a flowchart illustrating a control operation performed by the control unit 112 of the optical disk recording device 10. As described above, the optical disk recording device 10 is connected to the host PC 30 via the signal cable, receives the instruction signal from the host PC 30, and operates according to the instruction signal. Specifically, the instruction signal is roughly classified into an information recording instruction signal instructing that information is to be recorded on the optical disc 20 and an image forming instruction signal instructing that an image is to be formed. Each instruction signal includes speed information that defines the rotation speed (angular speed in the present embodiment) of the optical disc 20.
[0035]
As shown in FIG. 10, when receiving the instruction signal from host PC 30 (step S1), control unit 112 determines whether the received instruction signal is an information recording instruction signal or an image formation instruction signal. (Step S2). If the instruction signal is an information recording instruction signal, the control unit 112 controls each unit to execute OPC (step S3), and obtains a laser power characteristic as shown in FIG. 8 (step S4). Next, the control unit 112 acquires the ATIP information recorded on the recording surface of the optical disc 20, and specifies the type of the organic dye used for the recording layer 206 (Step S5). Next, the control unit 112 searches the media database 1120 using the type of the organic dye specified in step S5 as a search key, and reads a correction value corresponding to the type of the organic dye (step S6). Next, the control unit 112 corrects the laser power characteristic obtained in step S4 using the read correction value (step S7). Then, the control unit 112 controls each unit to rotate the optical disc 20 at the rotation speed (angular speed) indicated by the speed information, and irradiates the laser light from the optical pickup 104 according to the laser power characteristic corrected in step S7. The pits are formed on the recording surface of the optical disc 20 in accordance with the recording data sequentially supplied from the host PC 30 while adjusting the power of the optical disk 20 (step S8).
[0036]
On the other hand, if the result of determination in step S2 is that the instruction signal is an image formation instruction signal, the control unit 112 acquires media information and specifies the type of organic dye used on the recording surface of the optical disc 20 ( Step S9). Next, the control unit 112 searches the media database 1120 using the type of the organic dye specified in step S9 as a search key, and reads out a laser power optimum for the corresponding image formation (step S10). Then, the control unit 112 controls each unit of the optical disc recording apparatus 10 to form a dot corresponding to the gradation at each address of the optical disc 20 with the optimum laser power determined in step S10, and prints an image on the recording surface. Image formation control for forming is performed (step S11). Specifically, when the address indicated by the ATIP information from the ATIP detection circuit 109 is an address where a dot is to be formed, the control unit 112 irradiates the laser beam having the power determined in step S10. And outputs a power instruction signal to the laser power control circuit 124 in accordance with the linear velocity at that address. Specifically, in the CAV method, the linear velocity on the outer peripheral side is larger than the inner peripheral side of the optical disk 20. Therefore, when irradiating a constant laser power, the laser power is applied to the outer peripheral side of the optical disk 20. We need to increase it gradually. Therefore, the control unit 112 adjusts the laser power according to the linear velocity of the address to which the laser light is applied so that the laser light of the laser power determined in step S10 is applied. Next, the control unit repeats the operation of step S12 for all the dots forming the image, thereby forming, for example, a visible image as shown in FIG. 11 on the recording surface. In this operation example, a case where information recording and image formation are selectively instructed by an instruction signal has been described, but image formation may be performed subsequently after information recording is performed.
[0037]
As described above, in the present embodiment, at the time of information recording, the optimum laser power for forming pits is determined, so that information recording with good recording signal quality is performed. In addition, in the present embodiment, the laser power that increases the image contrast is recorded in the media database 1120 in advance for each type of organic dye that can be used in the recording layer 206 of the optical disc 20. Therefore, at the time of image formation, the optimal laser power is determined according to the type of the organic dye, and an image is formed with this laser power, so that the image contrast can be increased and an image with high visibility can be formed. The Rukoto.
[0038]
<Other modes of parameters used at the time of image formation>
In the above-described embodiment, the laser power is changed according to the type of the organic dye used for the recording layer 206 of the optical disc 20 during image formation. However, the present invention is not limited to this. For example, the irradiation time for irradiating a laser beam, the linear velocity at the time of forming an image (dot), and the like may be changed. More specifically, as described above, the degree of coloring of the recording layer 206 by laser light irradiation depends on the amount of heat per unit area generated by laser light irradiation. Further, the amount of heat depends on the laser power, the laser irradiation time, the spot diameter at the position where the laser light is irradiated, and the linear velocity of the optical disk 20 at the position where the laser light is irradiated. Therefore, instead of the laser power, any of the laser irradiation time, spot diameter, and linear velocity may be changed according to the type of the organic dye, or some of them may be changed at the same time. . In other words, it suffices that the amount of heat corresponding to the saturation point shown in FIG.
[0039]
More specifically, the control unit 112 determines a laser power, a laser irradiation time, a spot diameter, and a heat amount corresponding to the saturation point in advance for each organic dye so that the heat amount is generated at a place where a dot is to be formed. Further, each of the linear velocities may be changed. For example, in the media data 1120, a calorie calculated in advance is recorded for each of the organic dyes that can be used for the recording layer 206, and the control unit 112 determines the location where dots are to be formed according to the type of the organic dye. Any one or more of the laser power, the laser irradiation time, the spot diameter, and the linear velocity are changed so that the generated heat is generated by the laser light irradiation.
[0040]
In such a configuration, for example, when the laser irradiation time is changed, the control unit 112 controls the drive pulse generation unit 122 to change the laser pulse time width, and when the spot diameter is changed. First, the control unit 112 controls the servo circuit 108 to drive the focus actuator 1046 of the optical pickup 104 to change the focal position of the laser beam. Furthermore, when the linear velocity is changed, the control unit 112 controls the servo circuit 108 to change the rotation speed of the spindle motor 100. According to this modification, when the amount of heat corresponding to the saturation point is given by adjusting only the laser power, for example, the linear velocity is changed even if the laser power to be irradiated exceeds the rating of the LD. For example, heat corresponding to the type of the organic dye can be generated in the recording layer 206, and a high-contrast image can be formed. Further, by making it possible to change the laser power other than the laser power such as the laser irradiation time and the linear velocity, the LD can be operated within the rated range, thereby preventing the durability life of the LD from being shortened. In the media database 1120, a converted value obtained by converting the amount of heat at which the image contrast becomes substantially maximum into a laser power, a laser irradiation time, a spot diameter, or a linear velocity may be recorded.
[0041]
Further, as described above, in addition to applying the heat amount corresponding to the saturation point to the recording surface, the image contrast can be increased as follows. Generally, the image contrast changes depending on the ratio of the thermally discolored region in the unit area. The larger the ratio of the thermally discolored region, the higher the image contrast. Therefore, the media database 1120 may have a configuration in which a parameter defining the number of times of forming dots per unit area is recorded instead of the above-described laser power or the like. More specifically, in this configuration, the image dots are not formed along the pre-group 202a as described in the above-described embodiment, but as shown in FIG. N coordinates (indicated by black dots in the figure) are set on each of a large number of circles concentric with, and a dot corresponding to the color gradation is formed for each of the coordinates. Here, each circle is called a row, and the n coordinates set in each row are called a column.
[0042]
In such a configuration, if the diameter of each circle is set to a value that is close, that is, if each row is set to be close, a line (dot) formed per unit area as shown in FIG. ) Is increased, so that it is visually recognized that the image contrast is high. Therefore, to increase the image contrast, the amount of movement of the optical pickup 104 in the radial direction of the optical disc 20 (feed amount) is reduced, while to reduce the image contrast, the amount of feed is increased. . Therefore, a configuration may be adopted in which a feed feed amount required to obtain a desired image contrast is obtained in advance for each organic dye, and the feed feed amount thus obtained is recorded in the media database 1120 as a parameter.
[0043]
In a configuration in which dots are formed for each circle, during image formation, dots are formed for each circle from the innermost circumference to the outer circumference, or from the outermost circumference to the inner circumference. When dots are formed in one circle, the optical disk 20 is actually rotated (circulated) a plurality of times, and the tracking signal is the same in frequency and the same amplitude, but is different only in phase, for each round. Is set, and the irradiation locus of the laser beam is set to be different every round. More specifically, assuming that the number of rotations is N, the servo circuit 108 sets the passage timing of the radial reference line for defining the coordinate start point of each circle to zero on the time axis. A triangular wave signal whose phase is set to zero and whose phase is sequentially delayed by (2π / N) from the second round is generated as a tracking signal.
[0044]
When this tracking signal is supplied to the tracking actuator 1046b, the irradiation trajectory of the laser beam on the optical disk 20 changes from the trajectory (1) in the first lap to the N-th lap (N = N in the illustrated example), as shown in FIG. The results are different from each other up to the locus {circle around (7)} in 7). Note that the laser irradiation locus is actually a circular arc because the optical disc 20 rotates, but in this figure, the laser irradiation locus is linearly developed for convenience of explanation.
[0045]
As described above, when dots are formed for one circle, the irradiation trajectory of the laser light differs for each rotation. Therefore, in one rotation, the recording layer 206 is thermally discolored by the irradiation of the laser light, while the other rotation is performed. In this case, if thermal discoloration is not performed, the area ratio between the thermodiscolored portion and the undiscolored portion per unit area changes, thereby changing the image contrast. That is, if the image contrast is to be increased, the number of turns for performing thermal discoloration is increased, while if the image contrast is to be lowered, the number of turns is to be decreased. Therefore, the number of laps necessary to obtain a desired image contrast, that is, the number of overwrites is obtained in advance for each type of organic dye, and the number of overwrites thus determined is recorded as a parameter in the media database 1120. It may be.
[0046]
<Modification>
The above-described embodiment is merely an example and shows one mode of the present invention, and can be arbitrarily changed within the scope of the present invention. Therefore, various modifications will be described below.
[0047]
(Modification 1)
In the above-described embodiment, the configuration in which the laser light is turned on / off to form dots on the recording surface and the image is formed for each dot (pixel) forming the image has been exemplified. However, when a plurality of dots having the same color gradation are continuous, a configuration may be adopted in which these dots are formed by one laser light irradiation. Specifically, when the number of dots that have the same color gradation continuously is N, the control unit 112 sets the laser irradiation time to be N times the laser irradiation time when one dot is formed. Next, the driving pulse generator 122 is controlled. As described above, according to this modification, a plurality of dots are formed by one laser beam irradiation, so that the time required for image formation is reduced.
[0048]
(Modification 2)
In the above-described embodiment, the rotation driving method of the optical disc 20 is the CAV method. However, the rotation driving method of the optical disc 20 is such that the rotation speed is constant at a linear velocity, that is, the CLV (Constant Linear Velocity) method. Is also good. When the rotation driving method is the CLV method, the control unit 112 outputs an instruction signal indicating a linear velocity to the servo circuit 108 for controlling the rotation speed of the spindle motor 100. The method of driving the rotation of the optical disc 20 may be different between information recording (pit formation) and image formation (dot formation). In addition, during information recording and image formation, the CLV method and the CAV method may be switched according to, for example, the radial position of the optical disc 20 to be irradiated with laser light. When the CLV method is used as the rotation drive method of the optical disc 20, it is sufficient to record the optimum laser power at the time of image formation in the media database 1120 corresponding to the linear velocity at which the laser power can be set.
[0049]
(Modification 3)
In the above-described embodiment, the gradation of the image to be formed is set to two gradations, but is not limited thereto, and may be a multi-gradation of three or more gradations. More specifically, in the case of forming a multi-tone image, the control unit 112 forms the dot of the maximum tone (the tone having the highest density) with the laser power optimum for image formation, while the other dots are formed in the same manner. As for the tone, the dots are formed by gradually decreasing the laser power as the color density indicated by the gradation decreases. As described above, according to this modification, in the image formed on the recording surface, the contrast of the portion that should be darkest is increased, and furthermore, color development according to the gradient is obtained, so that an image with more expressive power is obtained. Can be formed.
[0050]
(Modification 4)
In the above-described embodiment, the optical disk apparatus that records information and forms an image on a CD-R is illustrated, but the present invention is not limited to this. In other words, any optical disk recording apparatus may be used as long as the optical reflectance changes due to the irradiation of the laser beam, and information is recorded on the optical disk such that discoloration occurs at the location where the optical reflectance changes. Such optical disk recording devices include a DVD-R (Digital Versatile Disc-Recordable) drive and a CD-RW drive. The optical disc 20 'used for the CD-RW differs from the optical disc 20 used for the CD-R in that the recording layer 206 does not contain an organic dye and uses a phase change material. The phase change material is a material that changes from crystalline to polycrystalline (amorphous) by irradiation with a laser beam. Examples of the phase change material include Ag-In-Sb-Te (silver-indium-antimony). -Tellurium) alloy materials. Generally, when the crystal structure of a phase change material is polycrystalline, the light reflectance is lower than that of the crystalline material, and a color different from that of the crystalline material is exhibited. Therefore, it is possible to form an image on a recording surface by applying this. To form a high-contrast image on the CD-RW optical disc 20 ', the following may be performed. That is, in a phase change material, the degree of color development (thermal discoloration) due to laser irradiation depends on the amount of heat generated per unit area by laser light irradiation. Therefore, the amount of heat required to obtain a desired image contrast is obtained in advance, and the laser power, the laser irradiation time, the spot diameter, and the linear velocity are set so that the heat amount is given to the recording layer 206 by laser light irradiation. May be controlled.
[0051]
(Modification 5)
In the above-described embodiment, the configuration in which the combination of the information recording parameter and the image forming parameter is recorded for each type of the organic dye in the media database 1120 is exemplified. However, the configuration is not limited thereto. More specifically, in the present invention, image formation control may be performed with optimal parameters for each optical disc 20 in order to increase image contrast, and the optical disc 20 may be uniquely specified. Therefore, for example, a combination of an information recording parameter and an image forming parameter may be recorded in the media database 1120 for each piece of identification information for identifying an optical disc. As the identification information, for example, a media ID, a manufacturer name, or the like can be used.
【The invention's effect】
As described above, according to the present invention, an optical disc recording apparatus capable of forming an image with high visibility on the recording surface of an optical disc is provided.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a functional configuration of an optical disc recording device according to an embodiment of the present invention.
FIG. 2 is a diagram showing a schematic configuration of the optical pickup.
FIG. 3 is a sectional view showing a configuration of the optical disc.
FIG. 4 is a schematic diagram showing a recording surface of the optical disc.
FIG. 5 is a conceptual diagram showing the media database.
FIG. 6 is a diagram for explaining the β value.
FIG. 7 is a diagram showing a relationship between the β value and jitter.
FIG. 8 is a view showing laser power characteristics obtained by the OPC.
FIG. 9 is a diagram showing the relationship between the laser power and image contrast for each type of organic dye.
FIG. 10 is a flowchart showing a processing procedure of the control unit.
FIG. 11 is a diagram showing a state in which an image is formed on a recording surface of the optical disc.
FIG. 12 is a diagram illustrating an image forming method according to another aspect.
FIG. 13 is a diagram for explaining image contrast.
FIG. 14 is a diagram for explaining an irradiation locus of a laser beam.
[Explanation of symbols]
Reference numeral 10: optical disk recording device, 20, 20 ': optical disk, 100: spindle motor, 104: optical pickup, 112: control unit, 122: drive pulse generation unit, 124 ... A laser power control circuit; 126, a stepping motor; 204, a recording layer; 1120, a media database.

Claims (2)

An optical disc recording device including an optical pickup that irradiates a laser beam onto a recording surface of an optical disc to record information, form an image, and read information recorded on the recording surface,
Storage means for storing an information recording parameter used for information recording and an image forming parameter used for image formation in combination for each piece of identification information for identifying an optical disc;
When recording information after controlling the optical pickup to read the identification information of the optical disc recorded in advance on the recording surface of the optical disc, the information recording parameter corresponding to the read identification information is stored in the storage means. To control the information to be recorded on the recording surface in accordance with the information recording parameter, and when forming an image, the image forming parameter corresponding to the read identification information is read from the storage unit. An optical disk recording apparatus comprising: a control unit that reads and controls an image to be formed in accordance with the image forming parameter. The optical disc recording apparatus according to claim 1, wherein the identification information includes information indicating a material used for a recording surface of the optical disc.

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