Magneto-optical disk device

[Detailed Description of the Invention]

(Field of the Invention) This invention is used mainly as external storages, such as a computer, It is related with the optical-magnetic disc equipment provided with the control circuit of the above-mentioned laser beam output for record in detail about the optical-magnetic disc equipment which consists of a mechanism which irradiates the magneto-optical disc as a recording medium with a laser beam, and records data. (PRIOR ART) As everyone knows, optical-magnetic disc equipment is an information storage device which records various kinds of information (data) reset to the digital signal on a magneto-optical disc so that rewriting is possible, and, therefore, the following principle requires the record and playback by the device. That is, magneto-optical discs are Tb (terbium), Fe (iron), and c. (Cobalt) etc. -- although the thin film which consists of a metal magnetic body arranges the magnetization direction and is vapor-deposited on the surface of the disc object Since the magnetization direction of the irradiation part will be reversed if it irradiates with the laser beam which converged and temperature is raised in the state where the magnetic field of the opposite direction was made to act on this, record of the digital signal which is zero to 1 signal is attained by providing the irradiation part and the non-glaring part of a laser beam. And also in the case of playback, if a magneto-optical disc is irradiated with a laser beam, the degree of rotation angle of the plane of polarization of catoptric light, or since it differs, zero signal and one signal which were recorded as mentioned above will be identified, and record data will be read in the portion which the magnetization direction reversed. By the way, Tb-Fe which consists of combination of the above-mentioned metal as a magnetic body on the surface of a magneto-optical disc. Since magnetic property changes with those composition, when recording or playing data to a magneto-optical disc, it is necessary to set up various kinds of conditions according to composition of a magnetic body, although the thing of various composition of Tb-Co5 Tb-Fe-Co etc. is used. And since exact record was not made unless the output (intensity) of the laser beam was appropriate when data was recorded especially, after specifying the kind of usually used magneto-optical disc beforehand, the optimal laser beam output for the magneto-optical disc was set up. (Problem which an invention tends to solve) as described above, since the kind of usable magneto-optical disc was specified, with the conventional optical-magnetic disc equipment, data was not able to be correctly recorded on any magneto-optical discs other than specification (a kind -- differing) in many cases. Therefore, especially when the magneto-optical disc which is not specified was used, the output of the laser beam for record needed to be readjusted. At the time of manufacture of a magneto-optical disc, precise composition control of a magnetic body thin film is difficult for an inconvenient thing, and it is the point that composition changes delicately with manufacture lots. That is, a magnetic body thin film is although it is formed by what is called a sputtering method apply an electron and ion to the charge of a metallic material (target), and make the metal atom which jumps out deposit on a base, It is because composition changes with the argon gas pressure and the targets as an atmosphere sensitively in this process. Generally, although the unevenness of film composition hardly occurs within the same magneto-optical disc, for the above-mentioned reason, another target is used, or manufacture time differs, and film composition has be [ many ] differences in the magneto-optical disc whose manufacture lot is not the same. Thus, in the conventional optical-magnetic disc equipment, since the output of the laser beam for record was set up beforehand, the kind of magneto-optical disc which can be used had restrictions, and when composition or the manufacture lot of the metal magnetic body film were not the same magneto-optical disc, there was a fault that exact record was not made. (Object) It was made in view of the above-mentioned point, the optimal laser beam output is automatically set up for each disk of every also to the magneto-optical disc from which film composition and a manufacture lot differ, and this invention tends to provide the optical-magnetic disc equipment with which exact record and faithful playback are attained. (Means for solving between Bending point) The place made into the gist of this invention for achieving the above-mentioned object, When irradiating a magneto-optical disc with a laser beam and making data record, the laser beam output which changes the above-mentioned laser beam output suitably beforehand, and records a specific signal and from which the playback signal optimal at the time of playback of those record signals is acquired is chosen, It is having provided the optical power control circuit which sets up the optimal output of the above-mentioned laser beam. (OPERATION) When data is recorded on a magneto-optical disc according to the optical-magnetic disc equipment of this invention, The optical power control circuit which carries out self-study and chooses the laser beam output from which changes a laser beam output to the specific part (test area) of the disk suitably, and records the specific signal for a test on it, it plays, and the optimal playback signal is acquired, Since the laser beam output at the time of data recording is set up and it records on a disk using the set-up optical power, exact record is made also to the magneto-optical disc from which a kind differs. (EXAMPLE) Hereinafter, the example of the optical-magnetic disc equipment of this invention is described based on a drawing. Drawing 1 is a flow chart which shows the data recording process of the optical-magnetic disc equipment concerning the 1st example of the present invention. As shown in the figure, it is a laser beam output control circuit in a device about magneto-optical disc l by which a format setup (A) was carried out and with which optical-magnetic disc equipment (not shown) was equipped in the device of this example (B), Self-study (C) of the optimal laser beam output is carried out beforehand, and data is recorded according to the commander from a controller after that (D). Data area 1a where a user scratches out data freely and which is made in the stage of the above-mentioned format setup (A) to magneto-optical disc l used with this device, Test area 1b for judging the characteristic of a disk (it opts for the optimal output of the laser beam for record) is set up as shown in Drawing 2, respectively. In the process of the above-mentioned self-study (C), as shown in Drawing 1, first, optical power is suitably changed to the portion of test area lb of magneto-optical disc 1 with which it was equipped in the device, and dispatch (a) Si and this are recorded for several sorts of laser beam signals for a test on it (b). And each recorded signal is reproduced and the signal for a test (record signal) and a digital demodulation signal with digital demodulation (c) Si, re-dispatch (d) Si It was and others are compared (e). As a result, the output of the signal for a test currently recorded most correctly is set up by considering the output of selection (f) Si and this selected signal as the optimal laser beam output (g). And record (D) of data is carried out by the laser beam output set up in the process of the above-mentioned self-study (C) on data area 1a in disk 1. the specific eight-to-fourteen modulation signal signal of a pattern with which outputs differ every for a while when an example of the laser beam signal for a test is shown here, as shown in 3rd [ The ] figure left column, p, and Sr1 ... is used. these abnormal-conditions signals -- one by one -- dispatch (a) Si Record (b) Si -- if digital Recoveryg (c) is reproduced and carried out, an error will arise to a digital demodulation signal, for example like the figure right column. And it is since the frequency (error rate) of this error becomes large so that the output of the laser beam signal at the time of the above-mentioned record is unsuitable, The difference in an error rate is measured by comparison (e) with the above-mentioned abnormal-conditions signal (record signal) and a recovery signal, and the signal output (here py) from which an error rate becomes the minimum is chosen ("). By the way, when recording data on magneto-optical disc l, the phenomenon which record in which a laser beam output is unsuitable and exact cannot be performed, but an error generates at the time of playback is explained as follows. For example, in Tb, film composition of a surface magnetic body obtains, and the relation between coercive force and temperature is denoted by curve 11 shown in Drawing 4 at the magneto-optical disc which are Fe and -3. And in order to reverse the magnetization direction of one part of disk l, with the magnetic field which a magnetic body film holds, the magnetic field of the strength of H+h is applied to an opposite direction, for example, it is irradiated with the laser beam on which the predetermined output converged, and the temperature of the portion is raised to it to the degree of 'lA of T, higher than A room 1jLT r. This temperature T and in order that strength H and h of a magnetic field may exceed the coercive force of a magnetic body film, the magnetization direction of one part where it was irradiated with the laser beam is reversed. Data is recorded by carrying out such and providing the irradiation part and the non-irradiation part of a laser beam on magneto-optical disc l based on a record signal. however, the information to which the output of the laser beam with which it irradiated was weak, and the temperature of the irradiation portion differed from data on disk l since magnetization reversal did not take place if it does not go up until, T and will be recorded. When the output of a laser beam is too strong conversely and the temperature of an irradiation portion exceeds T far, it will be in the state from which not only the irradiation part of a laser beam but the temperature of the circumference becomes T and the above, and magnetization reversal takes place where what is called a bit was expanded, and different information from data will be recorded. Therefore, when the record signal recorded in the state like a field person or the latter is reproduced, naturally it produces in an error, and if digital demodulation is carried out, there is an omission of a signal, or an excessive signal will enter. On the other hand, by another disk, when film composition is a little different Tbx'Fe+-x', it becomes the coercive force characteristic like curve 12 of Drawing 4, for example, and the above-mentioned disk will differ in the characteristic. In this case, above Tb. irradiating with the laser beam of the same output as the disk which has film composition of Fe+-* -- the temperature of an irradiation part -- T -- when it raises until, a pit will be expanded to the circumference of an irradiation part and exact record can be left. Drawing 5 is a flow chart which shows the data recording process of the optical-magnetic disc equipment concerning the 2nd example of the present invention. The same numerals as Drawing 1 are attached to the same portion as the 1st above-mentioned example. In this 2nd example, when choosing the optimal laser beam output by self-study (C), as a signal for a test, an output sends a high frequency signal different [ every ] for a while (n), and is made to record this (o). Since change of the envelope (Envelope rope) of a reproduction signal will become large so that a laser beam output is unsuitable if the recorded signal is reproduced (p), q out of which extracts Envelope rope change and it comes and which it spreads by a peak hold circuit etc., and the signal used as the minimum change are outputted with selection (r) Si, and it sets up by making this into the optimal laser beam signal (s). that is, signal Pl *, for example like 6th [ The ] figure left column, Pt', and P3' -- since it will become a reproduction signal like the figure right column if dispatch (n) Si and this are recorded and (o) reproduced for ... (p), Envelope rope change chooses from among these the advance withdrawal power of signal P2 * which becomes the minimum (r). in addition -- the two above-mentioned examples -- signals P7, P6, and P3 for a test ... or PIo, P2', P, and * ... although the optimal optical power is chosen and it was made to set up, after recording and reproducing [ send continuously and ] and carrying out the comparative examination of several sorts of signals The optimal optical power may be chosen, performing dispatch, record, reproduction, and a comparative examination for every signal. The above-mentioned self-study (C) may be made to be performed just before record (D), when the commander which records data is made instead of carrying out immediately after equipping with magneto-optical disc l in a device (B). (EFFECT OF THE INVENTION) Since the optical-magnetic disc equipment of this device consists of the above-mentioned composition, the following effects are produced. (1) Since the laser beam output for record is set as the optimal output and recorded for each magneto-optical disc of every, exact record is stabilized, and is made and a playback signal faithful to a record signal and good is acquired. (2) Since the laser beam output for record is automatically set as the optimal output value also when using the magneto-optical disc from which composition of a magnetic body film and a manufacture lot differ, an operator does not need to do troublesome adjustment work and it is convenient. (3) Since the device of the present invention corresponds also to the magneto-optical disc from which composition differs for every maker and it records by the optimal advance withdrawal power according to the effect of the above (1), the kind or maker of an usable magneto-optical disc do not have restrictions. (4) Since the best performance can be pulled out for each magneto-optical disc of every, the tolerance level of quality spreads and it also becomes possible to aim at the manufacturing cost fall of a magneto-optical disc.

[Brief Description of the Drawings]

The flow chart which shows the record process of the optical-magnetic disc equipment which requires Drawing 1 for the 1st example of the present invention, Drawings 3 are an explanatory view showing the format which sets Drawing 2 as a magneto-optical disc, and a wave form chart which illustrated the record signal for a test used in the 1st example, and its recovery signal, The graph Drawing 4 indicates the coercive force of the magnetic body film of a magneto-optical disc and the relation of temperature to be, the flow chart which shows a record process [ in / in Drawing 5 / the 2nd example ], and Drawing 6 are wave form charts which illustrated the record signal for a test used in the 2nd example, and its playback signal. ■ ... [ ... Self-study process. ] A magneto-optical disc, 1a ... A data area, 1b ... A test area, (C)