JP4564563B2 - Bar code recording device - Google Patents

Description

The present invention relates to a barcode recording apparatus for forming a barcode-like mark on an optical disc surface by laser light irradiation for the purpose of copyright protection and copy prevention.

Japanese Patent No. 3144422 Japanese Patent No. 3144423

  In general, many music CDs and movie DVDs using optical discs as recording media are sold. However, since the optical discs have characteristics that the recorded contents are not deteriorated by copying even if data is copied to other media, these optical discs are illegal. There was an increase in the number of copies and pirated discs, which could infringe the copyrights of content creators.

For the illegal copying, high-performance personal computers and free copy software that can be easily obtained are available, so even general personal computer users can use general optical disk drives without special skills or knowledge. Thus, the information recorded on the optical disk can be bit-transferred to a recording medium such as a write once optical disk / rewritable optical disk to easily create a clone disk. As for pirated discs, ROM-type disc manufacturing apparatuses can be obtained relatively easily and at a low price, and production in illegal areas is possible.

As one of the prior arts for preventing the illegal copy, a physical mark completely different from a pit (mark) containing content data (music / movie, etc.) is formed on an optical disk recording surface or a reflection film surface. Thus, a technique for controlling the reproduction and recording of content while identifying the original disc has been proposed. As an example of fully utilizing this technology, DV
This physical mark is bar code-like auxiliary data arranged in the circumferential direction on the inner peripheral side of the disc, and is called a BCA (Burst Cutting Area) code.

The physical mark is very difficult to duplicate because an arbitrary mark (data) is recorded by a special apparatus in a process after forming a laminated film such as a recording film in the manufacturing process of the optical disk. The mark portion by the bar code is formed by processing the reflectance to be low so as to satisfy a predetermined value because the reflectance of the other disk surface is high.

Examples of documents describing the technique and apparatus for recording marks on the optical disk described above include, for example, Japanese Patent No. 3144422 and Japanese Patent No. 3144423, and these documents include disk bonding in the optical disk manufacturing process. A technique for melting and removing a reflective layer of an optical disk using a YAG laser after the process is described.

In the above-mentioned prior art, it is described that the mark is formed by melting and removing the reflection layer of the optical disk using a laser. For example, the laser spot shape / laser for melting and removing the reflection film of the optical disk No specific technique such as laser irradiation technique / laser irradiation method such as temporal transition of output has been disclosed. In particular, so-called single-sided dual-layer discs that have two recording layers and are capable of reproducing data from both recording layers from one side have the property that laser light penetrates both layers at the same time. There was a problem that could not be recorded. Furthermore, in the prior art, when barcode data is recorded on a layer far from the reproduction surface side of a single-sided dual-layer disc, the laser beam must pass through the near layer, which reduces the recording efficiency of the far layer. There was also a bug to say. Furthermore, there was no technical description relating to bar code recording on a so-called single-sided multilayer optical disc having two or more recording layers on one side.

An object of the present invention is to eliminate the above-described problems caused by the prior art. Specifically, a barcode-like mark having different data for each recording layer is recorded and reproduced on a single-sided multilayer optical disc. It is an object to provide a bar code recording apparatus capable of recording bar code marks with good signals.

In order to achieve the above object, the present invention provides a barcode recording apparatus for recording a barcode on a single-sided multilayer optical disk that rotates in a predetermined direction, in which a laser beam is applied from the back side of the playback surface to the back surface opposite to the playback surface. A high-power semiconductor laser that irradiates through a lens and melts and removes the reflective layer on the disk recording layer to form a radially long linear laser spot, and the high-power semiconductor while synchronizing the rotation angle of the optical disk A first feature is that a laser driver circuit that changes a laser output of a laser in a pulse shape and a focus control circuit that focuses the laser spot on a recording layer closest to the back surface are provided.

According to the present invention, in the bar code recording apparatus according to the first feature, the laser driver circuit receives bar code data synchronized with disk rotation in reverse order, and the high- speed bar code data in accordance with the received reverse bar code data. power semiconductor laser to emit light in pulses and a second feature in that to overshoot the pulse rise portion of the laser output in a predetermined overshoot ratio.

The bar code recording apparatus according to the present invention automatically focuses a laser beam on the back surface opposite to the reproduction surface of a single-sided multilayer optical disk with a laser beam that is long in the radial direction on the disk recording layer via an objective lens. By irradiating in the form of pulses, it is possible to record a bar code mark with different data for each recording layer and record a bar code mark with a good reproduction signal on a single-sided multilayer optical disc.

Hereinafter, a barcode recording apparatus according to an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram for explaining a barcode recording apparatus to which a recording method according to the present embodiment is applied.
2 is a diagram for explaining a bar code recorded on an optical disc according to the present embodiment, FIG. 3 is a time chart of the bar code recording method according to the present embodiment, and FIG. 4 is a laser output in the longitudinal direction of the laser spot according to the present embodiment. FIG. 5 is a diagram illustrating the intensity distribution, FIG. 5 is a diagram for explaining the laser output according to the present embodiment, FIG. 6 is a diagram illustrating the relationship between the mark and laser spot position and output during bar code recording according to the present embodiment, and FIG. Is a diagram for explaining the focusing of the laser optical disc according to the present embodiment, FIG. 8 is a diagram for explaining a bar code recording method of a general single-sided dual-layer optical disc, and FIG. 9 is a diagram of the single-sided dual-layer optical disc according to the present embodiment. FIG. 10 is a diagram for explaining a barcode recording method, and FIG. 10 is a diagram for explaining a single-sided dual-layer optical disc.

<Premise explanation>
First, the definition of optical disks and terms that are the premise of the present invention will be described. As shown in FIG. 10, a single-sided dual-layer optical disc 3 to which the present invention is applied has a second recording layer 2 with a reflective layer on a base material, and a reflective layer in a semitransparent state on the second recording layer 2. The first recording layer 1 with a gap is disposed, and a transparent intermediate layer of several μm to 100 μm is sandwiched between the second recording layer 2 and the first recording layer 1, and the recording layer has two sides. This is a single-sided dual-layer optical disc. The single-sided dual-layer disc has a thickness of 10 nm to a data surface of a 0.6 mm-thick substrate made by injection molding a material such as polycarbonate.
A material formed by sputtering using a 100 nm aluminum alloy or the like as a reflective material, and a material formed by sputtering so that laser light can be transmitted through the data surface of another substrate manufactured by the same method. The data surfaces are bonded to each other with an adhesive of about several μm to 100 μm. In addition, the single-sided dual-layer disc is formed by sputtering using an aluminum alloy or the like having a thickness of 10 to 100 nm as a reflective material after forming a data surface on a polycarbonate substrate of 0.6 to 1.2 mm by the 2P method or the like. Then, an intermediate layer made of resin or the like having a thickness of several μm to 100 μm with the data surface transferred thereon is formed, and then sequentially laminated such that gold or silicon is formed by a sputtering method so that laser light can be transmitted. 10um ~ 3
It is made by arranging a 00 um transparent sheet or resin as a protective layer.

This single-sided dual-layer optical disk 3 is formed by irradiating laser light 4 from one side to each recording layer 1.
Alternatively, the information recorded in 2 can be reproduced, the incident side of the laser beam 4 for recording / reproducing data is the front surface 5 of the disk, and the other surface is called the back surface. In this structure, part of the laser beam 4 is transmitted in a semi-transparent state. The front surface 5 is also called a reproduction surface.

Further, as shown in FIG. 2, the optical disk recorded by the barcode recording apparatus according to the present embodiment has a plurality of marks (bars and spaces) in the form of a barcode extending radially from the rotation center of the disk on the inner peripheral side of the disk 75. Is formed with a bar code mark 76 along the circumferential direction of the disc.

Further, in the present specification, the rotation in the disc rotation direction 78 in which the content data or the barcode data can be reproduced by the incidence of the laser beam from the front surface 5 is assumed to be normal rotation. The order of the barcode data list that can be reproduced (disc circumferential direction 77) is assumed to be a forward arrangement, and the transfer of the barcode data recorded so as to be the forward arrangement in the forward rotation of the disc is referred to as forward feeding. Let the reflective layer of the layer mean melt removal. The rotation in the direction opposite to the forward direction is called reverse rotation.

<Description of configuration of barcode recording apparatus>
As shown in FIG. 1, the bar code recording apparatus according to the present embodiment includes a high-power semiconductor laser 6,
The objective lens 7 having a numerical aperture N of 0.5 <N <0.85 and a linear laser spot 9 that is long in the radial direction of the disk recording layer are irradiated, and the intensity distribution of the linear laser spot 9 is inclined. A spot tilting optical system 10 to be added, a multi-layer separation recognition optical system 13 for separating and recognizing the two recording layers 11 and 12 and generating a focus servo signal corresponding to each recording layer, and disc surface vibration The multi-layer focus control circuit 14 that performs focusing control by moving the objective lens 7 in the direction 7a so as not to cause a focus shift, the spindle motor 15 that rotationally drives the disk 27 in the direction 78 at a predetermined rotation number, and the motor A rotary encoder 16 for detecting the rotation angle of the disk in accordance with the rotation of the disk 15 and a modulation clock signal based on the rotation angle input from the encoder 16. A clock synchronization circuit 17 generated in synchronization, a modulation circuit 19 for generating an RZ signal 32 for recording on the disk surface based on the buffer data for bar code recording stored in the data buffer 18 and the modulation clock signal, and The serial RZ for one rotation of the optical disc is transferred by the transfer direction switching signal 21 for switching the order of the serial RZ signal series.
A data processing circuit 20 having a function of inverting the head and tail of the signal sequence in time, a laser driver circuit 22 for driving the semiconductor laser 6, an overshoot control circuit 23 for generating a pulse waveform to be described later, and a disk rotation Operation of the motor driver circuit 24 having a function of switching the direction, a carriage 25 for moving the spot condensed on the disk recording layer in the disk radial direction, and each circuit of the focus system / laser system / motor system / carriage system and the entire operation of the apparatus And a microprocessor (hereinafter referred to as MPU) 26 to be controlled.

<Description of operation>
Next, the operation of the barcode recording apparatus according to the present embodiment will be described with reference to FIGS.
First, the MPU 26 automatically records a barcode by preset programming while the optical disk 27 to be barcode-recorded is mounted on the spindle motor 15 so as to perform laser irradiation 28 from the front surface 5.

In this operation, the spindle motor 15 rotates the disk 27 in the normal rotation direction at a predetermined rotation speed according to an instruction from the motor driver circuit 24. The rotation method in this case is CLV (con
CAV (Constant ann) even in rotation of the linear linear velocity
Either rotation may be used. Next, the MPU 26 moves the carriage 25 to the barcode recording radius position on the optical disk 27, emits a laser beam with a bottom power 29 at a level where recording is not performed, and auto-focuses on the barcode recording layer by the multilayer focus control circuit 14. Apply control.

Next, the MPU 26 outputs the barcode data for barcode recording to the data buffer 18, and the serial buffer data 30 output from the data buffer 18 is synchronized with the disk rotation by the modulation circuit 19 using the modulation clock signal 31. RZ signal 32
And the forward direction designation to the data processing circuit 20 by the transfer direction switching signal 21, thereby transmitting the RZ signal 32 to the laser driver circuit 22 in the forward direction.

As a result, the laser driver circuit 22 amplifies the sequentially captured RZ signal 32 and gives an output instruction to the high-power semiconductor laser 6, so that the semiconductor laser 6 emits pulses at the same timing as the RZ signal 32. Start irradiation. As shown in FIG. 3, the top power 34 of the pulsed laser beam is set to be higher than the output at which the reflective layer of the disk recording layer starts to melt, and the bottom power 29 is set to an output that does not melt. In particular, the bottom power 29 is preferably reduced to such an extent that the focus is not lost.

As described above, the bar code recording apparatus according to the present embodiment synchronizes with the rotation of the optical disk and outputs the same pulse laser 33 every rotation of the disk, while the laser spot 40 cannot be recorded by the carriage 25 at a predetermined feed pitch. 35, a bar code 39 having a predetermined length in the radial direction in which the reflective layer 12 of the mark portion 37 is melted and removed.
Can be recorded. The recording data 38 for this bar code is a number “010011...” As shown at the bottom of FIG. The recorded data 38 can be reproduced and recognized by a general optical disk drive device or the like because the mark portion 37 from which the reflective layer is melted and removed has a low reflectance and the reflectance is sufficiently different from other disk surfaces. .

Furthermore, in this embodiment, since the disk rotation direction is normal and the barcode data is recorded in a forward sequence, the barcode data is recognized as expected barcode data even when reproduced by a general optical disk drive device or the like. Can do.

<Description of laser output>
Next, the spatial power distribution of the linear laser spot formed on the disk recording layer and the temporal change of the output will be described with reference to FIGS.
First, as shown in FIG. 4, the laser output distribution in the longitudinal direction of the laser spot according to the present embodiment is such that one end 53 (amplitude d) on the outer periphery side of the disk is larger than the other end 54 (amplitude c) and the amplitude thereof. The ratio (c / d) is set to 0.9 to 0.3, and the average of the laser output distribution is set to linear 51. The laser output overshoot output 50 is generated by the overshoot control circuit 23 shown in FIG. 1, and the power distribution in the short direction of the laser spot is preferably Gaussian.

The reason why the upper limit of the amplitude ratio is set to 0.9 is that the laser intensity distribution is uneven at several tens of percent as shown in FIG. 4, and 0.9 or less is preferable to enhance the effect of this inclination. The reason why the lower limit is set to 0.3 is based on the experimental result that the ratio of the minimum output at which melting can be removed to the minimum output at which deterioration starts is about three times, but at one end the melting cannot be removed and the other As long as it is within a range where deterioration can be prevented from occurring at the end of this, it is not strictly limited.

As shown in FIG. 5, the laser pulse output forms an overshoot output 50 having a region where the initial output abruptly rises / falls with respect to time. This overshoot output 50 is generated by the overshoot control circuit 23 shown in FIG.
The overshoot rate (a / b) can be set arbitrarily. In the pulse output according to the present embodiment, an overshoot rate (a / b) is set so that a good edge boundary 49 can be obtained at the leading portion 47 of the mark, and no molten reflector remains in the mark 44. Laser output (b
By setting -a), a good mark can be obtained. It is also effective when peeling occurs due to thermal expansion or thermal deformation of an adhesive or the like adjacent to the recording layer. As shown in FIG. 5, a good edge boundary can be obtained by providing a slight overshoot also at the rear end of the mark.

The overshoot rate (a / b) is preferably in the range of (1/10) to (2/3). The reason for setting this lower limit to (1/10) is that the laser intensity distribution is shown in FIG. In order to cover the effect of this unevenness and sharpen the mark edge (
1/10) or more is preferable, and the reason why the upper limit is set to (2/3) is based on the experimental result that the ratio between the lowest output that can be melted and removed and the lowest output that starts deterioration is about 3 times. As long as it can be prevented from being deteriorated at the top portion of the overshoot or being unable to be melted and removed at the flat portion of the output after overshoot, it is not strictly limited.

Next, the relationship between the radial laser output distribution and the pulse output over time will be described with reference to FIG. It is assumed that the longitudinal direction of the linear laser spot is arranged in the radial direction of the disk.

As shown in FIG. 6, the width (half-value width) 41 in the short direction of the laser spot, that is, the width of the laser spot in the disk circumferential direction 45 is set to at least ½ or less with respect to the recording mark width (circumferential direction) 42. . Therefore, in this embodiment, the reflection layer of the recording layer is not melted and penetrated at a stroke by laser pulse emission, but the reflection layer is gradually melted and removed while moving the laser spot in the scanning direction 43 in the disk circumferential direction 45. Works like this. Incidentally, a hatched portion 44 in the figure is a portion where the reflective layer is melted and removed.

In the present embodiment, as shown in the upper part of FIG. 6, since the overshoot is set so that the laser output 46 has a higher output at the mark head 47, the mark head 48 with less heat accumulation can be obtained. Melting can be performed at once (for a short time), and generation of semi-molten material or molten residue can be prevented at the edge boundary 49 corresponding to the mark head, and therefore the edge boundary 49 can be made clearly.

After the laser spot has passed the mark head, there is heat conduction from the head, and continuous melting is possible with a lower output than the head. The reflective layer material can be driven in the scanning direction 43 by the melt surface tension of the reflective layer material to remove the reflective layer. Thus, it is preferable to overshoot the laser output 46.

In addition, the laser output distribution 52 in FIG.
The reason for the arrangement on the traveling side 56 of the laser spot sent to 4 is that the mark 55 formed in the previous round of the disk rotation (in this case, the first round) has a thermal residue near the boundary 55 and the temperature is lower as it is farther from the boundary 55. The laser output is largely distributed on the farthest side from the boundary 55, that is, on the traveling side 56 of the laser spot to be sent in the radial direction 54, thereby starting melting at the position 57 that is the head of the mark farthest from the boundary 55. This is to spread the melt removal region at once.

The aforementioned laser output distribution is effective for improving the energy efficiency of mark formation and reducing the residual melt in the mark 44, and the inclined laser power distribution 5 in the laser spot longitudinal direction as shown in FIG.
2, it is desirable to adjust the amplitude ratio (c / d) so that the residual melt in the mark is reduced and is not unevenly distributed. Further, the rotational speed and feed amount of the disc are set so that a good state can be obtained between the mark portions and the marks.

<Explanation of focusing>
FIG. 7 is a schematic view in which a laser beam is incident from the front surface 5 side of the single-sided dual-layer disc, and each recording layer is focused. The bar code recording apparatus constructed in FIG. 1 makes it possible to adjust the focal point 61 to the recording layer 59 or 60 for recording the bar code on the optical disc as shown in FIG. However, the shape of the laser spot formed on the recording film does not change, and a laser spot having the maximum power density can always be secured in the recording layer.

Further, by using the objective lens 58 having a large NA, the incident angle θ [θ = sin−1 (
NA / n). Note that n can be a large refractive index of the protective layer or intermediate layer, and θ can be a large angle formed between a normal line perpendicular to the recording surface and incident light. That is, the area change of the laser spot is large with respect to the optical axis direction 62, and the power density of the laser can be drastically reduced at a position slightly shifted from the in-focus position 61.

In the present embodiment, when recording is performed while focusing on a recording layer to be barcode-recorded, recording is not performed up to the other recording layer adjacent thereto. Therefore, according to the present embodiment, the barcode recording 63 can be performed only on the target recording layer, and different barcode data can be recorded separately on both recording layers. It is also possible to record bar codes of different data successively by recording the bar code on one recording layer and then moving the focus to the other recording layer by focus jump. Note that it is conceivable that the laser light that has passed through the second recording 60 reaches the disk back surface 60a during recording on the recording layer 60, but even in this case, the laser light is sufficiently diffused, for example, the disk back surface 60a. Even if printing is applied to the material, it does not affect the melting or chemical change of the printing material.

Furthermore, it is necessary to apply high thermal energy in a short time to suppress peeling and deterioration with time in the vicinity of the reflective layer due to bar code recording, and to form a good mark. For this reason, it has a large NA that strongly narrows the laser beam. An objective lens is useful. A larger NA is desirable, but a practical value is preferably 0.5 <NA <0.85.

<Description of Second Embodiment>
Next, a barcode recording method for recording barcodes on the second recording layer of the single-sided, dual-layer optical disc according to the second embodiment of the present invention will be described. FIG. 8 is a diagram showing a method of recording a barcode on the second recording layer of a general single-sided dual-layer disc, and is for comparison with the present embodiment. The single-sided dual-layer disc is in a state before user printing on the back side.

Now, in a general barcode recording method, in the state in which the laser beam 65 is incident from the front surface 64 of the single-sided dual-layer optical disc 69 and the optical disc 69 is rotated in the normal rotation direction at a predetermined rotational speed, The focus 67 is focused on the recording layer 66, the focus control is applied to the second recording layer 66, and RZ
The serial data sequence group for one rotation of the disk converted into a signal is sent to the laser pulse driver circuit 22 in order, and the order of b0, b1, b2,... Bn-2, b1n-1, and bn in terms of time 6
8, the bar code “10010...” Is recorded on the second recording layer 67.

In this way, the same serial data sequence group synchronized with the rotation of the disk is sent in sequence to the laser pulse driver circuit 22 for each rotation of the disk, and the laser spot is sent in the radial direction at a predetermined feed pitch, whereby the second recording is performed. It is possible to record the barcode data in the order of arrangement on the layer 66.

FIG. 9 is a diagram showing a barcode recording method on the second recording layer of a single-sided dual layer disc according to the second embodiment of the present invention. In this embodiment, as shown in FIG.
In the state where the laser beam 71 is incident from the back surface 70 of No. 9 and the disk is rotated in the forward rotation direction, the second recording layer 72 is focused and the second recording layer 72 is subjected to focus control. In this case, since the laser beam is incident from the back surface of the disk, the recording layer close to the objective lens becomes the second recording layer. The serial data sequence group for one rotation of the disk converted into the RZ signal is sent back to the laser pulse driver circuit 22 and is temporally sent to bn, bn-1, bn-2,
... Bar codes “100...” Are recorded on the second recording layer 72 in the order 68a of b2, b1, b0.

As described above, in the present embodiment, the same serial data sequence group synchronized with the rotation of the disk is sent back to the laser pulse driver circuit 22 every rotation of the disk, and the laser spot is sent in the radial direction at a predetermined feed pitch. As a result, it is possible to record the barcode data in the forward order on the second recording layer.

<Description of Third Embodiment>
In the barcode recording method according to the third embodiment, the laser beam is arranged to be incident from the back surface of the single-sided double-layer optical disk. The disc is rotated in the reverse direction. Focus is applied to the second recording layer, and focus control is applied to the second recording layer. In this case, since the laser beam is incident from the back surface of the disk, the recording layer close to the objective lens becomes the second recording layer. The barcode data sequence group converted into the RZ signal is sent to the laser pulse driver circuit in a sequential manner, and is temporally b0, b1,
Recording is performed on the second recording layer in the order of b2,... bn-2, b1n-1, and bn. As a result, forward-order barcode data can be recorded on the second recording layer.

The forward and backward transmission of the serial data list group described above can be arbitrarily selected by the transfer direction switching signal 21 from the MPU 26 after the transmission direction is converted by the data processing circuit 20 of FIG. Further, the above-described normal rotation and inversion of the disk are performed by the motor driver circuit 24 of FIG.
It can be arbitrarily selected by a switching signal 74 from the PU 26.

As described above, in the second embodiment and the third embodiment of the present invention, it is possible to record in the forward order on the second recording layer by laser incidence from the back surface of the disk. First on a single-sided dual-layer disc
If the recording layer has a low transmittance, the power efficiency of bar code recording on the second recording layer is low, and marks cannot be formed uniformly, bar code recording by laser incidence from the back of the disk is effective.

In general, an objective lens is designed in consideration of the thickness of a transparent material such as a substrate or a protective sheet for protecting the recording layer so that optical aberrations do not occur on the condensed recording layer. When the thickness of the transmissive material changes due to incidence, it is preferable to add the transmissive material between the objective lens and the disk so that the designed thickness value is obtained. It is preferable to record the barcode from the back side of the disc before performing user printing on the back side of the disc. If at least the barcode recording area is not printed, barcode recording from the back side of the disc can be performed even after user printing on the back side of the disc.

In each of the above embodiments, a single-sided dual-layer disc has been described. However, the same effect can be obtained with a single-sided multilayer disc having three or more layers without being limited to two layers. In the above embodiment, bar code recording is shown on the inner periphery of the disc. However, the bar code may be provided on the middle or outer periphery without being limited to the inner periphery of the disc.

The figure for demonstrating the barcode recording device to which the recording method by one Embodiment of this invention is applied. The figure for demonstrating the barcode recorded on the optical disk by this embodiment. The time chart figure of the barcode recording method by this embodiment. The figure which shows laser output intensity distribution of the laser spot longitudinal direction by this embodiment. The figure for demonstrating the laser output intensity by this embodiment. The figure which shows the relationship between the mark in the barcode recording by this embodiment, the position of a laser spot, and an output. The figure for demonstrating the focusing of the laser optical disk by this embodiment. The figure for demonstrating the barcode recording method of a general single-sided double layer optical disk. The figure for demonstrating the barcode recording method of the single-sided double layer optical disk by the 2nd Embodiment of this invention. The figure for demonstrating the single-sided double layer optical disk used as the object of this invention.

Explanation of symbols

1: first recording layer, 2: second recording layer, 3: optical disk, 4: laser beam, 6: semiconductor laser, 7: objective lens, 9: laser spot, 10: spot tilt optical system, 12: reflection layer,
13: Multilayer separation recognition optical system, 14: Multilayer focus control circuit, 15: Spindle motor,
16: Rotary encoder, 17: Clock synchronization circuit, 18: Data buffer, 19: Modulation circuit, 20: Data processing circuit, 21: Transfer direction switching signal, 22: Laser driver circuit,
22: Laser pulse driver circuit, 23: Overshoot control circuit, 24: Motor driver circuit, 25: Carriage, 28: Laser irradiation, 29: Bottom power, 30: Serial buffer data, 31: Clock signal for modulation, 34: Top Power: 37: Mark part, 39: Bar code, 40: Laser spot.

Claims (2)

A barcode recording apparatus for recording a barcode on a single-sided multilayer optical disk rotating in a predetermined direction ,
A high-power semiconductor that forms a long, linear laser spot in the radial direction by irradiating the back surface opposite to the playback surface with laser light from the back side of the playback surface through the objective lens and melting and removing the reflective layer on the disk recording layer. A laser, a laser driver circuit that changes the laser output of the high-power semiconductor laser in a pulsed manner while synchronizing the rotation angle of the optical disc, and focus control for focusing the laser spot on the recording layer closest to the back surface A bar code recording apparatus comprising: a circuit. The laser driver circuit receives the barcode data synchronized with the disk rotation in reverse order, light is emitted in pulses to the high output semiconductor laser in accordance with the reverse order of the bar code data to the received, pulse rise portion of the laser output The bar code recording apparatus according to claim 1, wherein an overshoot is performed at a predetermined overshoot rate.

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