JPH08235643A - Optical disk apparatus and optical disk medium used for it - Google Patents

Abstract

PURPOSE: To evaluate the optimum condition of a recording and reproducing operation by an optical disk apparatus itself by a method wherein an optimum reference signal is recorded in an optical disk and the characteristic of the recorded reference signal is separated and measured. CONSTITUTION: An optical beam is controlled by a reference pattern generator in such a way that at least one out of the power and the phase width of the optical beam is changed according to a predetermined rule. Then, information pits 3 as pit patterns P1 , P2 ,...Pn which are changed by a predetermined rule at interpit distances of d1 , d2 ,...dn are recorded in track guide grooves 1 in a test region on an optical disk, and special marks 2 as synchronizing signals are put. In addition, the mask patterns are reevaluated, and the optimum range of the sensitivity, the optimum recording condition or the like of the optical disk is detected. Consequently, even without using a measuring apparatus for exclusive use, the optimum range of the sensitivity, the optimum recording condition or the like of the optical disk can be evaluated by an optical disk apparatus itself.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk and apparatus capable of recording / reproducing, and an optical disk and apparatus capable of obtaining optimum recording / reproducing conditions.

[0002]

2. Description of the Related Art Optical disc systems are expected as a high-density, large-capacity recording system. In the case of recordable / reproducible optical discs, a finely focused light beam is applied to a disc medium in which a photosensitive material whose optical properties are changed by light or heat energy by light is attached on glass. , Record and reproduce information. Here, in order to achieve high-density information recording / reproducing, the properties of the disk medium, the properties of the optical head for recording / reproducing (hereinafter referred to as read / write head), and the properties of the reproducing system are optimal. Must hold a good relationship. That is, the sensitivity of the disk medium, the recording pulse (write pulse)
Amplitude and pulse width, read and write light spot size and shape, automatic focus (hereinafter referred to as AF) and tracking (hereinafter referred to as TR) control status, and the frequency characteristics and detection accuracy of the playback circuit are constant. It is necessary to be held in a relationship.

By the way, the disk medium, the read / write head, the servo characteristics of the AF and TR, the reproduction circuit, etc. are manufactured and adjusted so as to have predetermined characteristics from the above-mentioned relations. Considering that any one of the characteristics has changed, it is difficult to determine from the result which characteristic has changed. This is because the result is observed only as the output signal from the reproduction circuit. On the other hand, the output of the playback circuit occurs as a comprehensive result of the size of the medium, the size and shape of the recorded information created on the medium, the characteristics of the read / write head, the state of the servo, etc. Cannot be separated.
However, when reading and writing on an optical disc, the size of the recorded information pit is 1 μmφ or less, and the size of the read / write light spot is 1 to 2 μmφ, which causes a servo characteristic deviation of about 0.1 μm. The equipment requires very high precision, large scale and therefore expensive equipment,
There is a problem that it is not possible to easily check each characteristic at the site of use.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide an optical disk and an optical disk apparatus for recording / reproducing information on / from the optical disk by easily knowing the characteristics of each constituent element without using a highly accurate and expensive measuring apparatus. The purpose is to absorb the characteristic variations and perform highly reliable recording and reproduction. That is, calibrate variations in characteristics such as recording sensitivity of individual optical disks and variations in characteristics such as optical power of optical disk devices, and record one optical disk in multiple optical disk devices without considering the characteristics by the user. Play,
Further, the present invention provides a technique that enables recording and reproducing of a plurality of optical disks with one optical disk device.

A conventional technique is disclosed in Japanese Patent Laid-Open No. 52-345.
Japanese Patent Laid-Open No. 0-52 discloses a device which performs recording and reproduction at the same time and controls a recording laser so as to maximize the reproduction output.
Further, Japanese Patent Application Laid-Open No. 53-9101 discloses a technique in which recording and reproduction are performed simultaneously, and a recording laser is controlled so that the duty of a reproduction signal becomes 50% during recording.

However, in these devices, the optimum range of the write pulse waveform (power or pulse width) for the optical disk is actually recorded in order to control the recording laser while monitoring the reproduction signal obtained during actual recording. It was not possible to know before playback, and no consideration was given to the reliability of recording and playback immediately after the start of recording.

[0007]

The present invention utilizes the fact that the optical disk device itself has a function as an extremely highly accurate measuring device, and measures each of the above characteristics by the device itself. However, as described above, the read signal is read by combining various factors. For this reason, the optimum reference signal is determined in advance for each characteristic to be measured, and the response (result) to this reference signal and knowledge about each characteristic are combined to determine each characteristic. It is to measure separately. The reference signal differs depending on the target characteristic to be measured, but all of them are built in advance on the disk medium.

Specifically, an optical beam having an information recording area and a test area is irradiated with a light beam to record and reproduce information in the information recording area, and a light beam returning from the optical disk is detected to form a reproduction signal. In the optical disc device, a generator of a reference pattern for controlling the light beam so as to form the above-mentioned reference signal in the test area of the optical disc is provided, and the write pulse of the light beam at the time of recording information by reproducing and evaluating the mark pattern. Detect the optimum range of the waveform.
In addition, the optical disc medium which optically records and reproduces information has an information recording area provided on the optical disc medium and a test area provided on at least one of an outer circumference and an inner circumference of the recording area. The reference signal described above is recorded in the test area.

From this, the sensitivity of the optical disk as well as the optimum range of the write pulse waveform (power or pulse width) for the optical disk can be known before actual recording / reproduction, and the characteristic variations between the optical disk and the optical disk device for recording / reproducing on / from the optical disk. Can be absorbed, and highly reliable recording and reproduction can be performed.

[0010]

The operation of the reference signal and the characteristic measurement by the reference signal will be described below.

The characteristics to be measured are as follows.

(1) Resolution (frequency characteristic) (2) Pit size (3) Modulation degree (4) Signal level (5) Servo (AF, TR) performance (6) Recording medium sensitivity (optimum recording condition) (7) Reproduction system characteristics (worst pattern, level fluctuation, etc.) A reference signal is prepared for each of these, but it is also possible to share or omit it as necessary. For the resolution of (1), a pit string in which the intervals of recording pits are modulated according to a regular rule may be used. At this time, some kinds of pit sizes should be built according to a predetermined standard. Information regarding (1), (2), (3), (4), (7), etc. is obtained from this reference signal. Pits are also shaded, phase detection (uneven pit)
It is desirable to prepare a shape and change the depth as well as the size of the uneven pit.

Predetermined pits are recorded with a predetermined number of power levels and write waveforms in the reference signal relating to (6).

The reference signal relating to (7) is obtained by modulating the track guide groove in a predetermined shape (pattern), and the characteristics of the disk and the servo system can be known from the response of the modulated pattern and the servo signal.

As described above, the reference signal has a pit pattern, a track guide groove pattern, a recording pattern, etc., whose shape or size is controlled in advance (quantitative information on the shape and size is known by another means). Consists of.

The characteristic evaluation is performed by comprehensively evaluating the response to each reference signal.

[0017]

EXAMPLES The present invention will be described in detail below with reference to examples.

FIG. 1 shows an embodiment of a reference pattern relating to resolution. Information pits 3 are recorded in the track guide grooves 1 formed spirally or concentrically on the disk, and the pit pattern is such that the distance between the pits changes according to a predetermined rule such as d ₁ , d ₂ , ..., D _n. . The number of pits having a pit distance of di is at least two (in the case of three in the figure), and the pit groups p ₁ , p ₂ , ..., P _n are separated by a sufficient distance Δ. The special mark 2 is inserted as a synchronization signal when reading and evaluating.

FIG. 2 shows an output time form from the head when the pattern of FIG. 1 is read. The read waveform is read in the form shown in the figure between the signal level 4 corresponding to the amount of reproduction light from the non-recorded disk surface and the zero level 5 when the reproduction light is zero. The signal levels 21 and 31 are recorded information 2 and 3 in FIG.
It corresponds to. The signal amplitude at a certain recording density Dj, that is, the distance dj between pits is defined by the signal level difference Sj between the pit center in the pj pattern and the middle of the adjacent pits. When the signal difference between the zero level 5 and the non-recording level 4 is A, the signal modulation degree mj in the pattern pj is mj = Sj / A.
Defined by

FIG. 3 shows the distance between pits (that is, recording density).
And the degree of modulation are shown. If the above-mentioned reference pattern is prepared by changing the pit size (pit diameter) γ, the characteristics shown in FIG. 3 can be obtained. The resolution can be evaluated from this characteristic. That is, it is possible to know whether or not the resolution of the target device has a predetermined value. Further, by consciously controlling the control of the automatic focus (AF), the relationship between the resolution characteristic, the AF characteristic, and the read light spot can be separately evaluated. That is, the head characteristics and the servo system can be evaluated.

FIG. 4 shows an embodiment of a reference pattern for examining the relationship between the guide groove structure and the TR signal. As shown in (a),
Subsequent to the pit 3 for synchronization, the depth of the guide groove is changed, for example, as shown by 100 to 104 in the sectional view of (b). By examining the TR signal for this pattern,
Servo signal detection system can be evaluated.

FIG. 5 shows the relationship between the guide groove depth h and the characteristic amount α related to the servo signal.

FIG. 6 shows an embodiment of a reference pattern for TR system evaluation in which the guide groove 1 is locally shaken left and right like 1-1, 1-2, 1-3 and the like. If the TR swing amount is known in advance, the relationship between the TR deviation and the TR signal, that is, the sensitivity of the TR detection system can be known.

FIG. 7 shows an example of a reference pattern relating to the sensitivity of the recording film and the optimum recording conditions. As shown in FIG. 7A or 7B, the waveform of power P and pulse width W is recorded as a write signal while being changed by a predetermined pattern as shown. If calibrated reference light is used for the recording device, more accurate evaluation can be performed.

FIG. 8 shows the reproduction output from the pits recorded with the write waveform of FIG. In FIG. 8, t indicates time. From this, the optimum range of the write pulse waveform (power and pulse width) can be known together with the sensitivity of the recording film.

FIG. 9 is a diagram showing the relationship between the write power P and the characteristic amount (for example, the degree of modulation or resolution) B of the reproduced signal. The reference patterns shown in FIGS. 1, 4 and 6 are easy to reproduce (replica), but FIG. 7 is for the purpose of knowing the characteristics of the recording film of each disc, so that each disc should be made individually. Become. The recording based on the reference pattern in FIG. 7 may be made at the time of inspecting the disc or the like. If the reference pattern shown in FIG. 1 is recorded at the same time as the pattern shown in FIG.
You can evaluate the resolution.

It should be noted that the original signal modulation in the optical disk device,
If a generator for the reference pattern as shown in FIG. 7 or FIG. 1 is provided in addition to the demodulation function, the recording / reproducing evaluation can be easily performed by the own device.

In order to record the above-mentioned reference signal, it is sufficient to have several tracks to 10 tracks. Therefore, the original recording capacity of the disc is hardly affected. In other words, the number of tracks for information recording is 30,000 or more, and when 230 tracks are used for the reference signal, it is 0.
It is 1% or less. Therefore, as shown in FIG. 10, a reference signal area T can be provided inside or outside the original information recording area U of the recording medium. Note that FIG. 10 shows only one side of the upper surface of the disk.

[0029]

As described above, according to the present invention, the optical head characteristics of the optical disk device, the servo signal system, and the read signal system are evaluated, and the sensitivity of the disk medium and the optimum recording condition are measured by using a dedicated measuring device. Instead, the optical disk device itself can be evaluated. In particular, in the optical disc device where each factor of each component is combined and appears in the result and it is usually difficult to separate each factor even with a dedicated measuring device, a highly accurate quantitative evaluation by the optical disc itself. In that respect, the practical effect is extremely large.

[Brief description of drawings]

FIG. 1 is a plan view showing an embodiment of a reference pattern according to the present invention.

FIG. 2 is a waveform diagram showing a read waveform of the pattern shown in FIG.

FIG. 3 is a graph showing characteristics obtained from the pattern of FIG.

FIG. 4 is a conceptual diagram showing an example of a reference pattern for evaluation of tracking characteristics.

5 is a graph showing the characteristics obtained from FIG.

FIG. 6 is a plan view showing another embodiment of reference patterns for tracking characteristic evaluation.

FIG. 7 is a waveform chart showing an example of a recording waveform relating to evaluation of recording characteristics.

8 is a waveform diagram showing a read waveform from the pattern of FIG.

9 is a recording characteristic diagram obtained by FIGS. 7 and 8. FIG.

FIG. 10 is a disk top view showing an example of a reference pattern recording location.

[Explanation of symbols]

1 ... track guide groove, d ₁ ~d _n ... pit distance, p ₁ ~
_pn ... Pit pattern, 2 ... Special mark, 3 ... Information pit.

Claims (3)

[Claims] 1. An optical disk which irradiates an optical disk having an information recording area and a test area with a light beam to record and reproduce information on the information recording area, and detects a light beam returning from the optical disk to form a reproduction signal. In the device,
A reference pattern generator for forming a mark pattern in a test area of the optical disc by controlling the light beam so that at least one of the power and the pulse width of the light beam is changed according to a predetermined rule. An optical disk device characterized by detecting the optimum range of a write pulse waveform of a light beam at the time of recording information by reproducing and evaluating a mark pattern. 2. An optical disk medium for optically recording and reproducing information, comprising an information recording area provided on the optical disk medium and at least one of an outer circumference and an inner circumference of the recording area. An optical disc medium having a test area, in which a predetermined mark is recorded by a test waveform in which a power level is changed in a predetermined pattern. 3. An optical disk medium for optically recording and reproducing information, comprising an information recording area provided on the optical disk medium and at least one of an outer circumference and an inner circumference of the recording area. An optical disk medium having a test area, in which a predetermined mark is recorded by a test waveform in which a pulse width is changed in a predetermined pattern.