JPH0351781Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an optical information recording/reproducing device for optically recording or reproducing information on mutually different information recording disks, such as a video disk and a digital audio disk.

[Prior Art] When recording and reproducing information by irradiating light onto an information recording disk, it is necessary to maintain the angle between the optical axis and the information recording disk in a predetermined relationship (ideally perpendicular).
FIGS. 2 and 3 show an arrangement for adjusting such an angle in a digital audio disc player. In the figure, 1 is a digital audio disk as an information recording disk.
2 is a pickup serving as a recording/reproducing means.
The pickup 2 has an objective lens 3 from which a laser beam 4 is irradiated onto the disk 1 to reproduce information. Reference numeral 5 denotes a light source such as a light emitting diode, and the light 6 emitted from it is reflected by the disk 1 and then enters two light receiving elements 7 and 8, which are aligned with the optical axis ( Angle detection means 9 for detecting the relative angle between the pickup 2) and the disk 1 is constituted.

When the optical axis is at a predetermined angle (ideally perpendicular) to the disk 1 and the desired characteristics (for example, jitter characteristics) are obtained, the light emitted from the light source 5 and reflected by the disk 1 is The angle detection means 9 is adjusted so that the difference between the output signals of the light receiving elements 7 and 8 resulting from the incident light becomes zero. As a result, if the angle of the optical axis deviates, the balance of the amount of light to the light receiving elements 7 and 8 will change, and a difference signal will appear, so if the drive means (not shown) of the pickup 2 is driven in response to this signal, Servo can be applied to always maintain the optical axis at a predetermined angle.

[Problem that the invention attempts to solve]

However, when such a device is applied to a so-called compatible recording/playback device that can record and play back both a large-diameter video disk and a small-diameter digital audio disk, the inclination of the optical axis of the laser beam, etc. Since the reference setting position is fixed, adjusting the tilt reference setting position so that it is optimal for reproducing information on one of the video disc and digital audio disc will make it optimal for reproducing information on the other. This resulted in a drawback that it became difficult to reproduce information from both different disks with a sufficient S/N ratio.

[Means for solving problems]

FIG. 1 shows a block diagram for adjusting the angle of the optical axis in the present invention (also in the present invention, the configuration of the angle detection means 9, etc. consisting of the light source 5 and the light receiving elements 7 and 8 is shown in FIGS. 2 and 3). (Similar to the case shown in the figure). The outputs of the light receiving elements 7 and 8 are transmitted to a differential amplifier 11.
The difference signal is supplied to the angle adjustment circuit 12 so that the angle of the pickup 2, and therefore the angle of the optical axis, can be adjusted. 13 is two or more types of disks on which signals are recorded in different formats;
For example, it is a discrimination means for discriminating between a video disc and a digital audio disc. This discrimination can be easily made by detecting, for example, differences in the thickness, outer diameter, weight, reflectance, center hole diameter, recorded or reproduced signal, etc. of the two disks. 14 is a gain control circuit provided between the light receiving element 7 and the differential amplifier 11;
The gain of the signal output to 1 can be controlled.

[Effect]

By the way, if the standard setting position of the tilt of Pickup 2 is adjusted to be optimal for a video disc (or digital audio disc), when the digital audio disc (video disc) is played back with this device, both discs will be Due to the different recording formats, it is not always possible to obtain sufficient characteristics. To explain this with reference to FIG. 4, for example, on a video disc, the television signal is FM-modulated and recorded, whereas on a digital audio disc, the television signal is recorded with FM modulation.
Audio signals (which may include video signals and other signals) are EFM-modulated and recorded as so-called digital signals. Therefore, during reproduction, it is preferable to maximize the level of the RF (HF) signal to be reproduced, for example in the case of a video disc, but it is desirable to minimize jitter in the case of a digital audio disc. Video disks and digital audio disks not only differ in thickness, outer diameter, weight, reflectance, center hole diameter, etc., but also differ in the materials forming the disks. Therefore, the degree of sagging when the disk is mounted on a spindle motor (not shown) also differs from one another. As a result, the relative angle θv between the optical axis and the disk at which the level of the RF signal is maximized when playing back a video disc does not necessarily match the angle θa at which the jitter is minimized when playing back a digital audio disc.
Therefore, if the angular reference position of the optical axis (pickup 2) is set to be optimal for the video disc, the jitter will no longer be at its minimum value when the digital audio disc is played back. Conversely, if the reference position is set to be optimal for a digital audio disc, the level of the RF signal will not reach its maximum value when the video disc is played back.

However, in the present invention, the discriminating means 13
The system determines whether the disc set in the recording/playback device is a video disc or a digital audio disc (of course, instructions may be given manually), and determines whether the Output a signal. The gain control circuit 14 controls the gain of the signal supplied from the light receiving element 7 to the differential amplifier 11 in response to the signal from the discrimination means 13, and when a video disc is set, the digital audio When the disk is set, the reference position of each pickup 2 is automatically set at the angle θa. Therefore, information can be reproduced in the best condition no matter which disk is set.

In the case described above, the reference position of the pickup 2 can be adjusted by controlling the input of the differential amplifier 11, but the output of the differential amplifier 11 is controlled in accordance with the output of the determining means 13. You can. That is, the DC voltage generator 15 may be provided so that a predetermined constant voltage is superimposed on the output of the differential amplifier 11 when one of the disks (for example, a digital audio disk) is detected. As a result, an offset is given to the output when the other disk is detected, and the reference setting position of the pickup 2 can be changed as in the case described above.

Furthermore, in the above embodiment, the reference position is set in relation to the RF signal and the amount of jitter.
It can also be associated with other information such as crosstalk and tracking error level. Furthermore, the present invention can be implemented not only in playback devices but also in recording devices.

[Effect] As described above, in the present invention, the reference setting position of the optical axis of the pickup is changed manually or automatically depending on the type of disk, so information can be recorded and played back in the optimum condition at all times. can.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of an angle adjustment device for adjusting the inclination angle of a pickup according to the present invention, Fig. 2 is a front view of a conventional angle adjustment device, and Fig. 3 is a plan view thereof.
FIG. 4 is a characteristic diagram thereof. 1...Disk, 2...Pickup, 3...
Objective lens, 4... Laser beam, 5... Light source,
6... Light, 7, 8... Light receiving element, 9... Angle detection means, 11... Differential amplifier, 12... Angle adjustment circuit, 13... Discrimination means, 14... Gain control circuit,
15...DC voltage generator.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) The information is optically transferred to a first information recording disk and a second information recording disk on which information is recorded and reproduced in a format different from that of the first information recording disk. An optical information recording/reproducing device for recording or reproducing information on an information recording disc, comprising: a recording means for recording or reproducing information by irradiating the information recording disc with light such as a laser beam; and a recording means for recording or reproducing information by irradiating the information recording disk with light such as a laser beam; An angle detection means for detecting a relative angle between a shaft and the information recording disk; and a reference setting angle of the optical axis with respect to the information recording disk by driving the recording and reproducing means in response to a signal from the angle detection means. an angle adjusting means for adjusting the angle to be different between when recording and reproducing on the first information recording disk and when recording and reproducing on the second information recording disk. Recording and playback device. (2) By detecting a difference in at least one of the thickness, outer diameter, weight, reflectance, center hole diameter, recording or reproduction signal between the first information recording disk and the second information recording disk. A utility model registration claim characterized in that at least one of the input and output of a differential amplifier used for adjusting the angle is automatically controlled by the determined output. 2. The optical information recording and reproducing device according to item 1.