JPS61165825A - Optical information recording method - Google Patents

Abstract

PURPOSE:To perform the recording and erasing operations with higher accuracy and a small error generation factor in a reading mode, by writing the information to be recorded at a prescribed position on a recording medium with a light beam of the optimum writing intensity at a prescribed shift speed. CONSTITUTION:A microcomputer 5 gives the test data given from a test data generator 9 to a writing device 7 and writes the data to an optical disk 4. Then the computer 5 reads the test data out of the disk 4 via a reading device 8 and compares it with the original test data supplied from the generator 9 to obtain an error generation factor. Thus it is possible to obtain the optimum writing intensity with which the error generation factor is minimized at each radius position (r) and at each revolving speed (v). This writing intensity is stored into a RAM10. Then the computer 5 writes the information fed from a data bus 6 and to be recorded or erased to the disk 4 with the optimum writing intensity stored in the RAM10 via the writing device 7.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to an optical information recording/reproducing method for recording/reproducing or erasing information by irradiating an optical information recording medium with a light beam. The present invention relates to an optical information recording and reproducing method for erasing or reproducing information without error by adjusting and irradiating a light beam with high intensity.

Prior Art and Problems In recent years, technology has been developed to record, erase, or reproduce necessary information on optical discs, optical cards, etc. (hereinafter referred to as optical discs) using laser beams such as semiconductor lasers to record audio signals, video signals, etc. is making remarkable progress. Generally, the information to be recorded or erased is digitized into a binary signal, the irradiation intensity of the laser beam is modulated to correspond to the irradiation or non-irradiation of the medium, and the information is physically recorded on an optical information recording medium such as an optical disk. Information is recorded by forming a pattern of changes in shape or magnetic properties, and information is erased by irradiating the recording medium with a light beam of intensity equal to or greater than that used during recording. , by restoring the deformation and magnetic changes caused by recording,
Recorded information is being deleted. In the following, recording and erasing will be simply referred to as writing because the basic operations are the same.

In this case, controlling the irradiation intensity of the laser beam becomes a very important issue. If the strength is too strong, it will destroy the base material of the optical disc, and if it is too weak, sufficient recording and erasing will not be possible. In either case, it is not possible to accurately record or erase information, and therefore it is not possible to perform reproduction with a low error occurrence rate. Therefore, in order to perform accurate recording and erasing, it is necessary to control the laser beam intensity so that it is always at the optimum value.

Another important factor in ensuring optimal intensity is the relative speed of movement of the light beam and the recording medium, such as an optical disk. Even when writing or erasing information at the same position on a recording medium, the faster the moving speed is, the shorter the laser beam irradiation time per unit area becomes. Therefore, the laser beam intensity must be controlled so that it becomes stronger as the moving speed increases. In order to perform such control, a method is generally used in which a certain relationship is determined in advance between the moving speed and the laser beam intensity, and during actual writing, the laser beam intensity corresponding to the moving speed is determined from the above relationship. It is.

Another problem with the prior art that must be considered in ensuring optimum strength is when using disk-shaped recording media (disks). That is, it is the position on the optical disc of the irradiation point when the disc is irradiated with a laser beam, more specifically, the position in the radial direction. For example, as shown in FIG. 3, when writing information on the inner track 2 on the optical disk 1 and writing information on the outer track 3, when the rotational speed of the optical disk 1 is constant, the laser beam This causes a difference in the relative speed of the optical disc to the track, and the laser beam irradiation time per unit area on the track is longer in the former than in the latter. Therefore, the laser beam intensity must be made weaker for the former than for the latter. That is, the intensity must be controlled so that the inner track becomes weaker. Conventionally, as a control method in such a case, a method using a filter whose transmittance changes stepwise, Brag
Some methods have already been proposed, such as a method using diffraction of g (for example, Japanese Patent Laid-Open No. 52-23902).

As described above, according to the prior art, as a method of controlling the laser beam intensity during writing to an optimal value, a method is adopted in which the laser beam intensity is uniformly determined according to certain preset conditions. For example, in intensity control regarding a position in the radial direction, intensity values are preset in one-to-one correspondence with each radius value. Therefore, the intensity value when writing to a track on a certain radius rl is uniformly determined to be the intensity PI, which is preset corresponding to this radius r1. The same holds true for intensity control regarding the relative moving speed of the recording medium with respect to the laser beam. When writing is actually performed using such a preset light beam intensity value, it cannot be guaranteed whether or not the intensity value is the optimum value. If the uniformly determined intensity value deviates from the optimum value for eel, accurate recording or erasing cannot be performed and an error will occur when reading the recorded information.

OBJECTS OF THE INVENTION It is therefore an object of the present invention to provide an optical information recording and reproducing method that can perform accurate recording and erasing with a low error rate during reading.

Summary of the Invention The present invention is characterized by an optical information recording and reproducing method for recording, reproducing, or erasing information as desired by irradiating an optical information recording medium with a light beam, the method comprising: In a shaped recording medium, desired information is recorded on a predetermined track on a radial circumference at a predetermined relative movement speed between the light beam and the recording medium, and by varying the light beam intensity in several ways. Then, the data written by changing each writing intensity (hereinafter referred to as writing) is read out and compared with the data before writing, and the error occurrence rate for each writing intensity is calculated. The minimum writing intensity is stored as the optimum writing intensity at the predetermined movement speed at the predetermined position on the recording medium, and the information to be recorded is moved to the predetermined position on the recording medium at the predetermined movement speed. The present invention is characterized in that it is possible to write with a light beam of the optimum writing intensity at a high speed, and to always maintain the optimum writing intensity to perform more accurate recording or erasing with less error occurrence rate during reading. be.

Embodiments of the Invention The present invention will be described below based on illustrative embodiments. 1st
The figure is a block diagram showing an example of an optical information recording/reproducing apparatus using an optical disk that performs the optical information recording/reproducing method according to the present invention. The optical disc 4 is an optical recording medium for recording information. The microcomputer 5 writes information sent from a data bus 6 of a host computer, etc., to the optical disk 4 via a writing device 7, and conversely reads information from the optical disk 4 via a reading device 8 to the data bus 6. send. Test data generator 9 provides test f-fi to microcomputer 5. This test data may be of any type as long as it always provides a constant pattern of data; for example, an RF multiplied signal may be used. R.A.F.
The y-th 0 is used as a trap to store data such as the optimum write strength. The radius sensor 1) detects the radial position r on the disk of the currently accessed track and provides this result to the microcomputer 5. This detection method may be any method, such as detecting the physical position of the laser head using a linear scale or encoder, or optically reading and detecting the address recorded on the optical disk. .

Further, the rotational speed sensor 12 detects the current rotational speed V of the optical disc and provides this result to the microcomputer 5. This detection method also includes a method of reading index marks on an optical disk, a method using a rotary encoder, etc.
Any method is fine.

Next, a method for optically recording, erasing, or writing information according to the present invention using this apparatus will be explained in order.

(1) Test data writing stage The microcomputer 5 provides the test data given from the test data generator 9 to the writing device 7, and writes the test data on the optical disc 4.
Write to. This writing is performed by changing the laser beam intensity P in several ways depending on, for example, the radial position r1 and the rotation speed vK, and can also be performed by changing at least one of the three parameters described above.

For example, for the case of rotational speed v = vl, each test data is first written in the track corresponding to the radial position tr = rl by changing the laser beam intensity P by Px, -PH1, and then r = rfi.

Similarly, writing is performed on the tracks corresponding to r=r@, . . . by changing the busy laser beam intensity P.

(2) Optimal write strength storage stage followed by microcomputer 5ti,! Each test data written on the optical disk 4 is read through the reading device f8, and compared with the original test data given from the test data generator 9, and the error rate (total data written) is calculated. Find the ratio of the number of incorrectly written data to the number of data written by mistake. This error occurrence rate is obtained for each case in which writing is performed by changing the three parameters, for example, the radial position r9, rotational speed V, and laser beam intensity P. For example, when the rotational speed v=vl, a result as shown in the graph of FIG. 2 is obtained. This graph shows the error rate versus laser beam intensity.
In the case of r1 and r! In the case of r, (rl<rt) K is 0.As mentioned above, if the laser beam intensity during writing is too strong or too weak, accurate recording or erasing will not be possible. Therefore, for each condition, there is an optimum write strength at which the error occurrence rate is the lowest. In the example shown in FIG. 2, the optimal write strength for rtr is pl, r-
In the case of r, it becomes P, which means K. In this way, the optimal writing strength that minimizes the error rate is determined for each radial direction Rr and each rotational speed V.
Save to AM1G.

(3) By performing operations beyond the stage of writing information to be recorded or erased, all optimal write strengths for writing under the conditions of a predetermined radial position r and a predetermined rotational speed V are stored in RAMl0. It turns out.

Therefore, the microcomputer 5 performs an operation of writing the information to be recorded or erased given from the data bus 6 onto the optical disk 4 via the writing device #7 at the optimum writing strength in the RAM 10.

By following such a three-step writing procedure, information can be recorded or erased under optimal conditions that always minimize the error rate.

Note that there are two methods: one is to use the same optical disc as the optical disc to which information is written in step (3) as the optical disc 4 on which test data is loaded in step (1), and the other is to use a different reference disc. Conceivable. In the former method, it is necessary to provide a dedicated area on the optical disk for writing test data. However, a magneto-optical disk in which data once written can be erased may have a configuration in which no dedicated area is provided.゛In the above embodiments, the shape of the optical information recording medium is exemplified as a disk-shaped disk, but it is not limited to a disk, but can also be a drum-shaped recording medium, a card-shaped recording medium, or a tape-shaped recording medium.
The present invention is applicable.

Further, in order to make the explanation clear, the embodiment has been described as having a test data generator, but the present invention is not limited to this, and the information (for example, recording data) can be generated based on information from a host computer. The error rate is determined via a microcomputer by recording the information signal on the recording medium while temporarily storing it in the RAM, and then immediately reproducing it and comparing the reproduced information with the information in the RAM. It is also possible to easily repeat the above operation by increasing the beam intensity and enter the next normal writing operation only when the error rate reaches a desired value.

Effects of the Invention As described above, according to the present invention, in an optical information recording and reproducing method for optically recording, erasing, or reproducing information on a recording medium, the error rate is minimized under each condition by writing data in advance. Since the light beam intensity is determined and the actual recording or erasing of information is performed according to this intensity, the optimum writing intensity can be maintained at all times, and the error rate during reading is slightly reduced and accurate recording or erasing can be performed. I can do it.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an example of an optical information recording and reproducing apparatus for carrying out the optical information recording and reproducing method according to the present invention, and FIG.
The figure is a graph showing the relationship between laser beam intensity and error rate, and FIG. 3 is an explanatory diagram showing how information is recorded on different tracks on an optical disk. 1...Optical disc 2.3...Track 4...Optical disk 5...Microcomputer 6...
・Data bus 7...Writing device 8...Reading device 9...Test data generator 10...RAM 1)...Radius Sensor 12...Rotational speed sensor Fig. 1

Claims (4)

[Claims] (1) In an optical information recording and reproducing method in which information is recorded, reproduced, or erased by irradiating an optical information recording medium with a light beam, a predetermined position of the light beam and the recording medium is placed at a predetermined position on the recording medium. writing predetermined data at a relative movement speed while varying the intensity of the light beam in several ways; and reading and writing each of the written data while varying the writing intensity of the light beam. Compare with the previous data to find the error rate for each light beam writing intensity,
storing the writing intensity at which the error occurrence rate is minimized as the optimum light beam writing intensity at the predetermined relative movement speed at the predetermined position on the recording medium; An optical information recording/reproducing method comprising the steps of: writing information to be recorded with a light beam having the optimal writing intensity at the predetermined relative movement speed. (2) The optical information recording and reproducing method according to claim 1, characterized in that a dedicated area for writing the test data is provided on the recording medium. (3) The optical information recording method according to claim 1, wherein the test data is written on a reference recording medium prepared separately from the recording medium on which the information to be recorded is written. (4) The optical information recording method according to any one of claims 1 to 3, characterized in that the optimum writing intensity is stored in a RAM.