JPH1173646A - Pit length adjusting device, optical disk master disk exposure device and optical disk driving device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simply form a pit where a regenerative waveform of a recorded pit is adjusted to an optimum length by individually adjusting front edge part and rear edge part of a recorded pulse without changing a recording position. SOLUTION: A first pulse Pi is obtained by delaying a prescribed pulse P with a first delay circuit 1 of a delay amount of an integer number (n) ×minimum resolution At, and a second pulse P2 is obtained by delaying the pulse P with a second delay circuit 2 of the delay amount of a reciprocal T of a recording frequency + the integer number (m) × Δt. Then, a third pulse P3 is generated by ADNDing both pulses with an AND circuit 3, and a fourth pulse P4 is generated by ORing both pulses with an OR circuit 4. Since the third, fourth pulses P3, P4 are pulse width corrected for a zero pulse PO delayed by the reciprocal T from the prescribed pulse P, pit length correction becomes possible without changing a pit central position even when a correction value is changed for a continuous pit. Thus, the third pulse P3 of a short pulse width for a high sensitive optical disk, and the fourth pulse P4 of a long pulse width for a low sensitive optical disk are inputted, and the length of the pit is adjusted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pit length adjusting device, an optical disk master exposure device, and an optical disk drive device.

[0002]

2. Description of the Related Art Conventionally, in an optical disk master exposure apparatus used for manufacturing an optical disk master, a glass master coated with a resist is rotated to form an AO (acousto-optic) modulator or an EO (electro-optic) modulator. After irradiating the laser on / off controlled by the recording pulse inputted to the glass master through a focusing objective lens, the glass master is developed to form recording pits on the glass master. In an optical disk drive device that records data on an optical disk using a laser,
By irradiating the multi-valued controlled laser onto the rotation-controlled optical disc via the focusing objective lens,
Recording pits are formed on the recording surface of the optical disk.

The pulse width of the recording pulse for forming the pit is an integral multiple of the reciprocal T of the recording frequency, or
As described in Japanese Patent Application Laid-Open No. 4-298822, the recording frequency is shortened by T from an integral multiple of the reciprocal T of the recording frequency. Also,
In the pit length adjusting device described in Japanese Patent Application Laid-Open No. 4-344324, a specified pulse is defined based on a pulse delayed by n × Δt times (where n is an integer and Δt is the minimum resolution). Is generated for a recording pulse shorter or longer by 2 × n × Δt time than the pulse width of the recording pulse.

[0004]

In the pit length adjusting device described in Japanese Patent Application Laid-Open No. 4-298822, a pit is formed by a recording pulse which is an integral multiple of the reciprocal T of the recording frequency and which is shorter than the integral multiple by T. if you did this,
In order to optimize the characteristics in the amplitude direction and time direction of the reproduced waveform of the pit generated by the recording pulse, it is necessary to finely adjust the laser power for recording, and the characteristics in the amplitude direction and time direction are optimal. There is a drawback that it is difficult to record with good reproducibility so that a proper reproduced waveform can be obtained.

In the pit length adjusting device described in Japanese Patent Application Laid-Open No. 4-344324, when the pulse width is changed, if the change amount of the pit length needs to be changed in continuous pits, for example, the delay amount is changed. When the parameter n is changed from n1 to n2, the space between the pit recorded by n1 and the pit recorded by n2 is represented by the linear velocity v of the recorded portion on the glass master or optical disk. At this time, since the length of the space is expected to be longer or shorter by (n2−n1) × Δt × v time, the reproduced waveform of the recorded pits has a disadvantage that the jitter component increases by the amount of the change. is there.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a pit length adjusting device, an optical disk master exposure device, and an optical disk drive device that can optimize the characteristics of the pit reproduction waveform in the amplitude direction and the time direction.

[0007]

According to a first aspect of the present invention, there is provided a pit length adjusting device for adjusting a pulse width of a prescribed pulse which is an integral multiple of a reciprocal T of a recording frequency. In the pit length adjusting device for adjusting the length of the pit formed on the recording surface, the specified pulse is n × Δt time (where n is an integer and Δt is the minimum resolution of the delay time of the specified pulse) ) A first delay circuit that outputs a delayed first pulse, and the above-mentioned prescribed pulse is T + m × Δt time (where T is the reciprocal of the recording frequency,
m is an integer) the second output of the delayed second pulse
A delay circuit, a logical product circuit for outputting a third pulse representing a result of logical product of the first pulse from the first delay circuit and the second pulse from the second delay circuit, and the first delay circuit And a logical sum circuit for outputting a fourth pulse representing a result of a logical sum of the first pulse from the second delay circuit and the second pulse from the second delay circuit.

According to the pit length adjusting apparatus of the first aspect, in the prescribed pulse having a pulse width that is an integral multiple of the reciprocal T of the recording frequency, the first pulse delayed by n × Δt with respect to the prescribed pulse is used. , T + m × △ t for the specified pulse
A third pulse is generated that represents the result of the AND of the second pulse delayed by the time. The third pulse thus obtained is different from the pulse obtained by delaying the prescribed pulse by T
The leading edge is shorter by m × Δt time and the trailing edge is Tn
× Δt time is shortened. Also, a fourth pulse representing a logical sum of a first pulse delayed by n × Δt with respect to the specified pulse and a second pulse delayed by T + m × Δt with respect to the specified pulse. Generate The fourth pulse thus obtained is such that the leading edge is longer by T−n × Δt time and the trailing edge is longer by m × Δt time with respect to the pulse whose prescribed pulse is delayed by T. become longer. By changing n and m using these third and fourth pulses, it is possible to change the pulse width with a high degree of freedom. For example, an optical disk master exposure apparatus or an optical disk drive apparatus using this pit length adjusting device In the above, when a pit recorded on an optical disk is reproduced, it is possible to obtain a reproduced waveform having characteristics in the amplitude direction and the time direction that are optimal.

A pit length adjusting device according to a second aspect of the present invention is the pit length adjusting device according to the first aspect, wherein the minimum resolution Δt of the delay time of the prescribed pulse is set to the reciprocal Tmi of the maximum recording frequency.
It is characterized by being 10% or less of n.

According to the pit length adjusting device of the second aspect, by setting the minimum resolution Δt to be 10% or less of the reciprocal Tmin of the maximum recording frequency at which the reciprocal T of the recording frequency is the shortest, The pulse width of the fourth pulse can be finely adjusted, and the pit length recorded on the optical disk can be adjusted more precisely.

According to a third aspect of the present invention, there is provided an optical disc master disc exposure apparatus including the pit length adjusting device according to the first or second aspect.

According to the third aspect of the present invention, when exposing the optical disk master, the pit length adjusting device adjusts the recording pulse width to adjust the length of the pits to be recorded on the optical disk master. This makes it possible to optimize the reproduction waveform of the pits recorded on the optical disk manufactured by using the optical disk master manufactured through the exposure process.

According to a fourth aspect of the present invention, an optical disk drive device includes the pit length adjusting device according to the first or second aspect.

According to the optical disk drive of the fourth aspect, when recording pits on the optical disk, the recording pulse width is adjusted by the pit length adjusting device to adjust the length of the pits to be recorded on the optical disk. Thus, the reproduction waveform of the pits recorded on the optical disc can be optimized.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a pit length adjusting apparatus, an optical disk master exposure apparatus, and an optical disk drive apparatus according to the present invention will be described in detail with reference to the illustrated embodiments.

FIG. 1 is a circuit diagram of a pit length adjusting device according to an embodiment of the present invention. This pit length adjusting device receives a specified pulse P having a pulse width that is an integral multiple of the reciprocal T of the recording frequency, and outputs a first pulse P ₁ delayed from the specified pulse P; P, a second delay circuit 2 that outputs a second pulse P ₂ delayed from the specified pulse P, and a first pulse P ₁ from the first delay circuit _1.
When receiving the second pulse P ₂ from the second delay circuit 2, the first pulse P ₁ and the third representing the results of the second logical product of the pulse P ₂
AND circuit ₃ for outputting pulse P ₃ , first pulse P ₁ from first delay circuit ₁ and second pulse from second delay circuit 2
Receiving a pulse P _2, the first pulse P ₁ and the second pulse P ₂
And a logical OR circuit 4 for outputting a fourth pulse P ₄ indicating the result of the logical OR. The pit length adjustment circuit adjusts a pulse width with respect to a prescribed pulse P when forming pits on the optical disk master of the optical disk master exposure apparatus or when forming pits on the recording surface of the optical disk of the optical disk drive. .

The operation of adjusting the pit length for the prescribed pulse P having a pulse width of 3T in the pit length adjusting device having the above configuration will be described with reference to FIG. Note that n, m
Is an integer, and Δt is the minimum unit of time for delaying the recording pulse.

In FIG. 2, by inputting a specified pulse P having a pulse width of 3T to the first delay circuit 1 having a delay amount of n × Δt time, it is delayed by n × Δt time from the specified pulse P. first obtaining a pulse P ₁ has (Fig. 2 (a), (C) ).
Further, by inputting the specified pulse P to the second delay circuit 2 having a delay amount of T + m × Δt time, the second pulse P delayed by T + m × Δt time from the specified pulse P is input.
₂ is obtained (FIG. 2 (D)). By inputting the first and second pulses P ₁ and P ₂ to the AND circuit 3, a third pulse P ₃ representing the result of ANDing the _first and second pulses P ₁ and P ₂ is generated. (FIG. 2E). Further, the first and second pulses P ₁ , P _1
2 to the OR circuit 4, the fourth pulse P ₄ representing the result of ORing the first and second pulses P ₁ and P ₂
Is generated (FIG. 2 (F)). The third thus obtained
Pulse P ₃ is specified pulse P the front edge of the 0 pulse P _0, which is delayed by T only m × △ t time short, trailing edge T
It becomes shorter by the time −n × Δt (FIGS. 2B and 2E). Further, the fourth pulse P ₄ is such that the leading edge of the zeroth pulse P ₀ is T
The length is longer by −n × Δt time and the trailing edge is longer by m × Δt time (FIGS. 2B and 2F). The third and fourth pulses P ₃ ,
P _4, in order to correct the pulse width with respect zeroth pulse P _0, which is delayed by T always from prescribed pulse P, even when changing the correction value for successive pits, changing the center position of a pit Without this, the pit length can be corrected. Note that the 0 pulse P ₀ as a reference, because the delayed always reciprocal T of the recording frequency for the specified pulse P,
In an optical disk master exposure apparatus and an optical disk drive apparatus, a correction is made to advance a recording signal by T when recording a pit.

[0019] Thus the recording pulse obtained by using a laser on / off control for the sensitive optical disc, type a short pulse width as in the third pulse P _3, sensitivity for low optical disc by entering longer the pulse width as in the fourth pulse P _4, it is possible to adjust the length of the pit formed on the recording surface of the optical disc master and an optical disk, a reproduction waveform As a result, a waveform having good characteristics in the amplitude direction and the time direction can be obtained.

FIG. 3 is a block diagram showing an optical disk master exposure apparatus using the pit length adjusting device.

As shown in FIG. 3, the optical disk master exposure apparatus includes a frequency generator 11 for generating a recording frequency,
A recording information storage unit 12 for receiving a signal from the frequency generator 11 and outputting a signal representing stored recording information (for example, track address information);
A data encoder 13 for receiving a signal from the recording information storage section 12 and a recording signal representing recording information from the recording information storage section 12, and modulating the recording signal according to a predetermined modulation method; And a pulse width correction circuit 14 that receives the recording signal representing the modulated recording information from the controller, corrects the pulse width of the recording signal, and outputs a recording signal with the corrected pulse width. The pulse width correction circuit 14 has the pit length adjusting device shown in FIG. Further, the optical disc master disc exposure apparatus receives a signal from the recording information storage unit 12 and outputs a signal representing the stored radial position data, and a radius from the radial position data unit 8. An exposure light quantity data section 19 for receiving a signal representing the position data and outputting a signal representing the exposure light quantity based on the stored exposure light quantity data;
4 and the exposure light amount data section 1
9, an exposure light quantity setting circuit 15 for setting an exposure light quantity and outputting a control signal to an optical disc exposure section 16, and applying a laser beam to a glass master 17 based on the control signal. And an optical disk exposure section 16 for irradiating.

In the optical disk master exposure apparatus having the above-described configuration, a signal representing recording information is output from the recording information storage section 12 in synchronization with the recording frequency generated by the frequency generator 11, and the signal representing the recording information is converted into data. The signal is modulated by the encoder 13 into a recording signal to be written on the optical disk. Then, the pulse width of the recording signal modulated by the data encoder 13 is corrected by a pulse width correction circuit 14. Further, based on a signal representing the radial position data from the radial position data section 18, the exposure light amount data section 19 is output.
Is input to the exposure light quantity setting circuit 15. The exposure light amount setting circuit 15 sends a control signal to the optical disk exposure unit 16 based on the recording signal whose pulse width has been corrected from the pulse width correction circuit 14 and a signal representing the exposure light amount data from the exposure light amount data unit 19. Output. Then, the optical disk exposure unit 16
Irradiates modulated light onto a circular glass master 17 rotating at a constant rotation speed based on a control signal, and exposes pits corresponding to the recording signal. The surface of the glass master 17 is coated with a resist in advance.

Thereafter, the resist on the exposed glass master 17 is developed to form a pattern, and then a metal plate is formed on the glass master 17 by electroforming.
A master optical disc is manufactured from the metal plate peeled off from the base plate.

As described above, in the process of manufacturing the optical disc master, when exposing the glass master by the optical disc master exposing device, the pulse width of the recording signal is adjusted by the pit length adjusting device of the pulse width correcting circuit 14 to adjust the glass width. By adjusting the length of the pits formed on the master, it is possible to optimize the reproduction waveform of the pits of the optical disc manufactured by the optical disc master manufactured through the exposure process.

FIG. 4 is a block diagram of an optical disk drive using the pit length adjusting device.
In the block diagram of the optical disk drive shown in FIG. 4, components relating to reading of an optical disk are omitted.

As shown in FIG. 4, the optical disk drive includes a frequency generator 21 for generating a recording frequency,
A recording information storage unit 22 that receives a signal from the frequency generator 21 and outputs a signal representing stored recording information;
A data encoder 23 that receives a signal from the frequency generator 21 and a recording signal representing recording information from the recording information storage unit 22 and modulates the recording signal according to a predetermined modulation scheme; A pulse width correction circuit that receives the signal and the modulated recording signal from the data encoder 23, corrects the pulse width of the recording signal, and outputs a recording signal with the corrected pulse width. The pulse width correction circuit 24 has the pit length adjusting device shown in FIG. Further, the optical disk drive device comprises: an address data section 28 for outputting a signal representing the stored address data;
And a laser light amount data unit 29 for receiving a signal indicating address data from the CPU and outputting a signal indicating the laser light amount based on the stored laser light amount data. The recording information storage unit 22 outputs a recording signal indicating recording information based on a signal indicating a writing address and data from the writing command unit 30. The address data section 28 outputs a frequency command signal corresponding to the address to the frequency generator 21 based on a signal representing a write address and data from the write command section 30. That is, the recording frequency is changed according to the address of the optical disk on which the writing is performed. The optical disk drive receives the corrected recording signal from the pulse width correction circuit 24 and the signal indicating the laser light amount from the laser light amount data unit 29 and outputs a control signal to the optical disk drive optical system 26. And an optical disk drive optical system 26 that irradiates a laser whose on / off and output are controlled to a predetermined position of a rotation-controlled optical disk 27 based on the control signal.

In the optical disk drive having the above structure, a signal representing recording information is output from the recording information storage section 22 in synchronization with the recording frequency generated by the frequency generator 21, and the signal representing the recording information is converted to a data encoder. The signal is modulated by 23 into a recording signal to be written on the optical disk. Then, the pulse width of the recording signal modulated by the data encoder 23 is corrected by a pulse width correction circuit 24 having a pit length adjusting device shown in FIG. Further, based on the signal representing the address data from the address data section 28, a signal representing the laser light quantity data determined by the laser light quantity data section 29 is input to the laser modulation circuit 15. The laser modulation circuit 15 sends a control signal to the optical disk drive optical system 26 on the basis of the pulse width corrected recording signal from the pulse width correction circuit 24 and a signal representing the laser light amount data from the laser light amount data section 29. Output. Then, the optical disk drive optical system 2
6 irradiates a laser beam to the optical disk 27 whose rotation is controlled based on the control signal, and records pits corresponding to the recording signal on the recording surface of the optical disk 27.

As described above, when pits are recorded on the optical disk in the optical disk drive device, the pulse width of the recording signal is adjusted by the pit length adjusting device of the pulse width correction circuit 24 to determine the length of the pits to be recorded on the optical disk. Is adjusted, the reproduction waveform of the pits of the optical disk can be optimized.

In the above embodiment, the optical disk master exposing device and the optical disk drive device using the pit length adjusting device of the present invention have been described. However, the configurations of the optical disk master exposing device and the optical disk drive device are not limited to the above embodiment. Of course not. The pit length adjusting device of the present invention is not limited to the optical disk master exposing device and the optical disk drive device, but may be applied to other optical information recording devices.

[0030]

As is apparent from the above description, the pit length adjusting apparatus according to the first aspect of the present invention adjusts the pulse width with respect to a prescribed pulse that is an integral multiple of the reciprocal T of the recording frequency, thereby obtaining the recording surface of the optical disk. In a pit length adjusting device for adjusting a pit length when a pit is formed on a pit, a prescribed pulse is given by n.times..DELTA.t time (where n is an integer and .DELTA.t is a minimum delay time of the prescribed pulse). A first pulse delayed by a second pulse is output from the second delay circuit, and a second pulse delayed by T + m × Δt (where T is the reciprocal of the recording frequency and m is an integer) is output from the second delay circuit. The logical product circuit takes the logical product of the first and second pulses, outputs the third pulse representing the result of the logical product, and obtains the logical sum of the first and second pulses by the logical sum circuit. And display the result of the disjunction. The fourth pulse is output.

Therefore, according to the pit length adjusting apparatus of the present invention, the leading edge and the trailing edge of the recording pulse can be separately adjusted without changing the recording position in the continuous pulse. The pits whose lengths are adjusted can be easily formed on the recording surface of the optical disk so that the reproduced waveform of the recorded pits is optimized.

The pit length adjusting device according to the second aspect of the present invention is the pit length adjusting device according to the first aspect, wherein the minimum resolution Δt of the delay time of the prescribed pulse is set to 10% or less of the reciprocal Tmin of the maximum recording frequency. It was done.

Therefore, according to the pit length adjusting device of the second aspect, the pit length is adjusted with higher accuracy by setting the minimum resolution to be delayed to 10% or less of the reciprocal of the maximum recording frequency of the optical disk. be able to.

According to a third aspect of the present invention, an optical disk master exposure apparatus includes the pit length adjusting device according to the first or second aspect.

According to the third aspect of the present invention, when exposing the optical disk master, the pit length adjusting device adjusts the recording pulse width to adjust the length of the pits to be recorded on the optical disk master. By performing the adjustment, it is possible to optimize the reproduction waveform of the pits of the optical disk manufactured from the optical disk master manufactured through the exposure process.

An optical disk drive according to a fourth aspect of the present invention includes the pit length adjusting device according to the first or second aspect.

Therefore, according to the optical disk drive of the invention, when recording pits on the optical disk, the pit length adjusting device adjusts the recording pulse width to adjust the length of the pits to be recorded on the optical disk. By doing so, it is possible to optimize the reproduction waveform of the pits recorded on the optical disk.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of a pit length adjusting device according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating correction of a pulse width of the pit length adjusting device.

FIG. 3 is a block diagram of an optical disk master exposure apparatus using the pit length adjusting device.

FIG. 4 is a block diagram of an optical disk drive device using the pit length adjusting device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... 1st delay circuit, 2 ... 2nd delay circuit, 3 ... AND circuit, 4 ... OR circuit, 11, 21 ... Frequency generator, 12,
22: Recorded information storage unit, 13, 23: Data encoder, 14, 24: Pulse width correction circuit, 15: Exposure light amount setting circuit, 16: Optical disk exposure unit, 17: Glass master, 18: Radial position data unit, 19 ... Exposure light amount data section, 25 ... Laser modulation circuit, 26 ... Optical disk drive optical system, 27 ... Optical disk, 28 ... Address data section,
29: laser light quantity data section, 30: write command section.

Claims (4)

[Claims] 1. A pit length adjusting device for adjusting the length of a pit formed on a recording surface of an optical disk by adjusting a pulse width with respect to a prescribed pulse that is an integral multiple of a reciprocal T of a recording frequency. The prescribed pulse is n × △ t time (where n is an integer, △
t is the minimum resolution of the delay time of the specified pulse, a first delay circuit that outputs a delayed first pulse, and the specified pulse is T + m × Δt time (where T is the reciprocal of the recording frequency and m is A second delay circuit that outputs a delayed second pulse, and a second delay circuit that represents a result of a logical product of the first pulse from the first delay circuit and the second pulse from the second delay circuit. An AND circuit that outputs three pulses; an OR circuit that outputs a fourth pulse representing a result of the OR of the first pulse from the first delay circuit and the second pulse from the second delay circuit; A pit length adjusting device comprising: 2. The pit length adjusting device according to claim 1, wherein a minimum resolution Δt of the delay time of the prescribed pulse is set to 10% or less of a reciprocal Tmin of a maximum recording frequency. . 3. An optical disk master exposure apparatus comprising the pit length adjusting device according to claim 1. 4. An optical disk drive device comprising the pit length adjusting device according to claim 1.