JPS60239926A - Optical information detector - Google Patents

Abstract

PURPOSE:To suppress degradation of information recording materials of a recording medium and to improve the life of an optical information recording medium by making the output of a semiconductor laser at a track seek time lower than an information reading time. CONSTITUTION:The reflected light from an optical disc 1 is received by an information reading means to read information recorded on a recording track 3. The optical disc 1 is rotated and driven by a motor at the track seek time, the information reading time, and an information recording time. A sequence control circuit 7 sets an output signal S to the low level again to set the track seek mode when information read is terminated. At the information recording time, a large current is flowed to a semiconductor laser D in accordance with information to be recorded, and pits 2 are formed on the recording track 3 of the optical disc. Since the output of the laser at the track seek time is made lower than the information reading time, degradation of information recording materials is suppressed to improve the life of the optical information recording medium.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to an optical information detection device that performs track seeking and information reading on an optical information recording medium.

(Prior art) An optical information detection device uses a light beam from a semiconductor laser to irradiate a spiral or coaxial recording track of an optical information recording medium made of an optical disk in an optical disk device in a minute slit. Receiving reflected light and recording 1
-It is known to read information recorded on a rack. - The information recording material for light distribution discs is mainly metal-based materials. However, organic materials have recently attracted attention and have been created as information recording materials that have characteristics that metal materials do not have.

Figure 1 shows two optical discs using a metallic information recording material and an organic information recording material with the same sensitivity.
It shows the relationship between the semiconductor laser irradiation output when the output of the semiconductor laser is irradiated at a linear velocity and the reflectance of the information recording surface of the photon disk after the semiconductor laser output irradiation.

By the way, an optical disk device records and reads information on an optical disk, and when recording information, the amount of light from the semiconductor laser is changed depending on the information to be recorded. Information is recorded by forming the information on the recording track 1 to easy on the optical disc, and when reading the information, the difference in reflectance between the pit 1 and the non-pit area on the recording track of the optical disc is also used as an information signal. . In Fig. 1, when reading information, the irradiation output of the semiconductor laser to the optical disk is 0 point, or the reflectance of the information recording material of the optical disk changes by reading the information (by irradiation with the semiconductor laser output ■). If this happens, it means that the information recording material has deteriorated, so it is necessary to prevent this from happening. However, when the organic information recording material of the optical disk is irradiated with the semiconductor laser output (2), it deteriorates by the amount a of the decrease in reflectance, albeit slightly, and the life of the optical disk is shortened.

(Objective) An object of the present invention is to provide an optical information detection device that can extend the life of an optical disc.

(Structure) The present invention will be described below based on examples with reference to the drawings.

FIG. 3 shows an embodiment of the invention. In this embodiment, in a conventional optical disk device, the output of the semiconductor laser is not made the same as when reading information from 11 to 11, but is changed to be lower than when reading information. An optical disk device irradiates an optical disk with the output of a semiconductor laser not only when recording information and reading information, but also when performing a 1-rack seek (searching for 1 to 1 rack on which information should be recorded or read). During track seeking, the spot produced by the laser output irradiation of the semiconductor 1 on the optical disc crosses the line 3 where the bit 2 of the optical disc 1 is formed, as shown in FIG. 2, as the optical device moves. The reflected light from the optical disc 1 is received by the 1-rack detection circuit 4, and a sinusoidal 1-rack signal is detected. This track detection circuit 4 detects a track error by detecting the deviation between the spot 81 and the rack 3 from the reflected light from the optical disc 1. Even if the irradiation output is at point 0, which is lower than point 0 in FIG. 1, the track signal can be detected sufficiently.

The track signal from the rack detection circuit 4 is sent to the tracks 3 to 5 to be counted and sent to the servo system drive circuit 6. The sequence control circuit 7 sets the output signal S to a low level during the 1-rack seek mode as the 1-rack seek mode. The semiconductor laser 1.0 is driven by a drive circuit consisting of transistors Try and Tr2 and resistors R4, and its drive current is switched by the output signal S of the sequence control circuit 7. At the time of track seek, the output signal S of the sequence control circuit 7 becomes low level, so the transistor T+1 is turned off, and the semiconductor laser 1.11 has a current 2 flowing through the transistor Tr2, and the output becomes 0 point. At this time, the servo system drive circuit 6 does not apply the tracking servo to the optical device based on the signal from the sequence control circuit 7. In the track seek mode, the sequence control circuit 7 causes a motor to move the optical device in the radial direction of the optical disc 1 to perform track seeking, but when a desired track is detected from the contents of the track number counter 5, the sequence control circuit 7 enters the information reading (number change) mode. As a result, the output signal S is set to high level. Therefore, the transistor Tri is turned on, and the drive current of the semiconductor=4 integrated lasers 1 and D increases by the current I, and the driving current of the semiconductor lasers 1 and 1 is increased by the current I.
r] irradiation output becomes 0 point. At this time, the servo system drive circuit 6 is operated by the signal from the sequence control circuit 7, and 1
- The optical device is moved in the radial direction of the optical disc 1 by a motor according to the signal from the rack detection circuit 4, and tracking servo is applied. Further, the reflected light from the optical disc 1 is received by the conventional information reading means, and the information recorded on the recording 1-rack 3 is read. The optical disc 1 is rotationally driven by a motor during track seeking, information reading, and information recording. When the sequence control circuit 7 finishes reading the information, it sets the track seek mode again and sets the output signal S to a low level. During information recording, a large current is applied to the semiconductor laser 1.11 by a conventional information recording means in accordance with the information to be recorded, thereby forming pips 1 and 2 on the recording track 3 of the optical disc 1.

(Effects) As described above, according to the present invention, the output of the semiconductor laser is made lower during track seeking than when reading information, thereby suppressing deterioration of the information recording material of the optical information recording medium and improving the life of the optical information recording medium. You can do two things:

[Brief explanation of drawings]

FIG. 1 is a characteristic curve diagram showing the characteristics of the information recording material, FIG. 2 is a diagram showing the relationship between recording 1-rack and 1-rack signals on an optical disc, and FIG. 3 is a circuit showing an embodiment of the present invention. It is a diagram. 1, D... semiconductor laser, Trl, Tr2...1
- Runsistor, 7... Sequence control circuit. =71

Claims (1)

[Claims] In an optical information detection device that performs track seeking and information reading by irradiating an optical information recording medium with a light beam from a semiconductor laser as a minute spot and receiving the light from the optical information recording medium, The optical information detection device is characterized in that it is provided with means for lowering the output during 1-rack seeking than when reading information.