JPH01112529A - Method for recording optical information - Google Patents

Abstract

PURPOSE:To simplify the control of a recorded laser power by decreasing the radiation time of a light beam in a region where the relative speed is small and the information of the shortest recorded pit period is recorded shorter than a half the shortest recording pit period. CONSTITUTION:If there is a difference partially or totally in the relative moving speed between the beam and an optical information recording medium, the radiation time of the light beam is made shorter than a half the shortest recording pit period T in the region where at least the relative speed is small and the information of the shortest recording pit period T is recorded so as to reduce the radiated light energy thereby reducing the recorded laser power dependancy and the relative speed dependancy on the S/N at the highest frequency. Thus, the control of recorded laser power is simplified.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an optical information recording method, and particularly relates to an optical information recording method in which the relative moving speed between an optical information recording medium and a light beam is partially or totally varied. The present invention relates to an optical information recording method in which information is recorded by irradiating a light beam onto an optical information recording medium.

[Prior art and its problems] Conventionally, in order to record on write-once type and erasable type optical memory disks, the recording laser diode has been set so that the lighting time ratio of the recording laser is 50% at the highest writing frequency. The recording was done by modulating the

However, in the prior art example E, the S/N ratio during reproduction at the highest frequency largely depends on the recording laser power and linear velocity, and thus had the following problems.

(1) Recording laser power must be strictly controlled.

(2) The recording sensitivity of optical memory disks must be strictly controlled during production.

(3) When an optical memory disk is rotated at a constant angular velocity in order to shorten the access time, the recording laser power must be varied depending on the radial position to be recorded.

[Means for Solving the Problems] The optical information recording method of the present invention is characterized in that the relative movement speed between the optical information recording medium and the light beam varies partially or completely. In an optical information recording method in which information is recorded by irradiating a light beam onto a medium, the light beam The beam lighting time is set to half () of the shortest recording pit period (''').
It is characterized by being shorter than T/2).

[Function] In the case where the relative moving speed between the optical information recording medium and the light beam partially or completely differs, the present invention provides at least one shortest recording pit period (
By making the lighting time of the light beam shorter than half (T/2) of the shortest recording pit period (T) in the area where the information of T) is recorded, the irradiated light energy can be reduced.
This aims to reduce the dependence of the S/N ratio on recording laser power and relative speed at the highest frequency.

[Example] Hereinafter, embodiments of the present invention will be described in detail using the drawings.

As already mentioned, the present invention reduces the irradiated light energy by making the lighting time of the light beam shorter than half (T/2) of the shortest recording pit period (T). If the lighting time of the light beam is made too short, it is necessary to set the recording laser power very high, and the writing efficiency decreases. Therefore, it is desirable to set the ratio of the light beam lighting time to the shortest recording pit period ('") (hereinafter referred to as the light beam lighting time ratio) to 10% to 40%, more preferably 15%. It is desirable to set it to % to 30%.

Specific examples will be described below.

(Embodiment 1) FIG. 1 is a signal waveform diagram for explaining the optical information recording method of the present invention.

In FIG. 1, 1 is a recording data string, 2 is a recording signal, and 3 is a recording data string.
is the lighting signal for the recording laser diode. The lighting signal 3 of the recording laser diode was controlled to be shorter than the recording signal 2 by a fixed time t, so that the lighting time ratio of the recording laser diode was 20%.

A magneto-optical disk with a diameter of 13 cm was used as the optical memory disk, and the disk was rotated at a constant angular velocity of 1500 rpm, and the frequency of recording signal 2 was set to 3 MHz.
FIG. 2 shows the relationship between the N ratio and the recording laser power.

(Comparative Example 1) For comparison, the lighting time ratio of the recording laser diode was set to 50%, and the other conditions were the same as in Example 1.
FIG. 3 shows the relationship between the iQ raw S/N ratio and the recording laser power at a radius of 60 mm and a radius of 60 mm.

In addition, in Example 1, the range of recording laser power in which a reproduction S/N ratio of 20 dB or more is obtained is shown in FIG.

Further, in Comparative Example i, the range of recording laser power in which a reproduction S/N ratio of 20 dB or more is obtained is shown in FIG.

From FIG. 2, FIG. 4, FIG. 3, and FIG. 5, compared to Comparative Example 1, Example 1 has a wider usable recording laser power range, the recording laser power can be easily controlled, and the optical memory disk It can be seen that the management of the characteristics becomes easier.

(Example 2) The lighting time of the recording laser was adjusted according to the i diameter so that at a radius of 30 mm, the lighting time ratio of the recording laser was 20%, and at a radius of 60 mm, the lighting time ratio of the recording laser was 50%. The ratio was changed continuously, and the other conditions were as in Example 1.
Recording was done in the same manner. At this time, the playback S/N ratio is 2
FIG. 6 shows the range of recording power in which 0 d 8 or more can be obtained.

By changing the lighting time ratio of the recording laser according to the radial position, the usable recording laser power range is further expanded than in the first embodiment.

(Example 3) From a radius of 30 mm to a radius of 45 mm, the lighting time ratio of the recording laser was set to 20%, and from a radius of 45 mm to a radius of 6 mm.
At 0mm, the lighting time ratio of the recording laser is set to 50%.
Other than that, recording was performed in the same manner as in Example 1. FIG. 7 shows the recording power range in which a reproduction SZN ratio of 20 dB or more can be obtained at this time.

Although the method of changing the recording laser power in this example is simpler than in Example 2, the same practical effects were obtained.

[Effects of the Invention] As explained above in detail, according to the optical information recording method of the present invention, at least in the area where the relative velocity is small and information with the shortest recording pit period ('T) is recorded,
The irradiation time of the light beam is defined as the shortest recording pit period (T).
By making it shorter than half (T/2) of
It becomes possible to prevent a decrease in the N ratio, and the control of the recording laser power can be simplified.

[Brief explanation of the drawing]

1st [! 4 is a signal waveform diagram for explaining the optical information recording method of the present invention. FIG. 2 is a characteristic diagram showing the relationship between reproduction S/N ratio and recording laser power in Example 1 of the optical information recording method of the present invention. FIG. 3 is a characteristic diagram showing the relationship between the reproduction S/N ratio and the recording laser power in Comparative Example 1. FIG. 4 is a characteristic diagram showing the range of recording laser power in which a reproduction S/N ratio of 20 dB or more can be obtained in Example 1 of the optical information recording method of the present invention. FIG. 5 is a characteristic diagram showing the range of recording laser power in which a reproduction S/N ratio of 20 dB or more can be obtained in a comparative example. FIGS. 6 and 7 are characteristic diagrams showing the range of recording laser power in which a reproduction S/N ratio of 20 dB or more can be obtained in Example 2 and Example 3 of the optical information recording method of the present invention. 1: Recording data string, 2: Recording signal, 3: Recording laser diode lighting signal. Agent Patent Attorney Minoru Yamashita 1 Mizuki 1

Claims (1)

[Claims] (1) An optical method in which information is recorded by irradiating a light beam onto an optical information recording medium while the relative movement speed between the optical information recording medium and the light beam varies partially or completely. In the information recording method, at least in an area where the relative speed is small and information with the shortest recording pit period (T) is recorded, the lighting time of the light beam is set to half (T/2) of the shortest recording pit period (T).
) An optical information recording method characterized in that the length is shorter than .