JPS6344329A - Optical information recording and reproducing device - Google Patents

Abstract

PURPOSE:To execute the reading without generating the deterioration of a reproducing signal by using the tracking error detecting means for controlling a tracking, detecting the inclination of a disk and correcting the inclination of the light axis of an information reproducing device with the detecting value. CONSTITUTION:A light beam for recording and reproducing information is radiated onto the track of an information disk surface and the reflecting light is received by a light receiving element 70 of an optical pick-up. By removing direct current components ic and id to show the inclination of a disk through an LPF 8 for the output signal of the element 70, inputting this to operational amplifier 10 and operating ic-id, the inclination detecting signal of the disk is obtained. Further, by driving a motor 12 through a driver 11 with the detecting signal, the inclination of an optical pick-up is corrected, the orthogonal relation of the laser beam light axis and the disk surface of the optical pick-up is maintained and the comatic aberration occurrence of a beam spot can be eliminated. The tracking error component of the output of the element 70 can be detected through an HPF9.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an optical information recording/reproducing device, and particularly to a tilt servo (skew servo) thereof.

[Conventional technology]

The conventional device was equipped with an independent optical system for detecting tilt (skew), as described in Japanese Patent Application Laid-Open No. 59-152530. However, no consideration was given to the use of the ±1st-order beams of the laser beams used for tracking control to detect the inclination of the disk.

[Problem that the invention seeks to solve]

In conventional optical information recording and reproducing devices, a gas laser (He-Ne laser) is used as a light source for reading information.
However, as devices have become smaller and lighter,
There is a shift to semiconductor lasers.

In a pigeon house using a semiconductor laser as the light source, the wavelength λ of the semiconductor laser is about 780 nm, and He
It is longer than that of Ne (62A 8 nm). Therefore, the light beam of the semiconductor laser is transferred to He-N on the recording disk surface.
In order to narrow down the light to the same degree as the convergent light of the e-gas laser, the N A (Nume
rical Apertura) at least Q,
I really need to make it a big one with 5 stands.

However, when the NA of the objective lens is increased, it increases in proportion to the cube of the disk due to the tilt of the information recording disk, so the playback characteristics of the device become more susceptible to the influence of the disk tilt. . Therefore, it is necessary to prevent the deterioration of various reproduced signals caused by the tilt of the disk.

SUMMARY OF THE INVENTION An object of the present invention is to provide an optical information recording and reproducing apparatus that detects the inclination of a disc by a simple means and makes it possible to correct the inclination.

[Means for solving problems]

The above purpose is to detect the inclination of the disk by using a tracking error detection means used for tracking control,
This is achieved by controlling an inclination adjustment means for correcting the inclination of the optical axis of the information reproducing apparatus based on the detected value, and maintaining the orthogonal relationship between the optical axis and the disk.

[Effect]

In order to achieve the above object, the present invention irradiates the recording surface of a disk with ±1st-order diffracted light of a laser beam for information reading in a tracking error detection means used for tracking control of an information reproducing apparatus, and detects the reflected light. The inclination of the disk is detected by using the DC component contained in the reproduction signal of the optical information reading device obtained by receiving the light with the light receiving element, and the orthogonal relationship between the optical axis of the information reading device and the disk is determined from the detected value. The optical axis is controlled so that the optical axis is maintained, so to speak, by using unnecessary parts of the tracking error signal, and tilt servo (skew servo) is performed without affecting tracking control. Therefore, the reproduction characteristics will not deteriorate.

〔Example〕

FIG. 2 is an explanatory diagram showing the outline of the optical recording information reproducing apparatus according to the present invention, in which 4 is an optical disk on which information is recorded on the reflective surface, and 2 is an objective lens 6 that directs a laser beam onto the reflective surface of the optical disk 4. 1 is a mechanism for holding the optical pickup so as to tilt it in accordance with the deviation of the orthogonal relationship between the optical axis of the optical pickup and the optical disk 4.

The laser light emitted from the optical pickup 2 and irradiated through the objective lens 3 is reflected on the optical disk reflective surface by the third laser beam.
It is in the state shown in the figure. The laser light is split by a diffraction grating in the optical pickup. 6 indicates ±1st-order light of the laser beam, and 7 indicates 0th-order light. Further, 5 is an information recording track on the reflective surface of the optical disk. Generally, tracking control using the three-beam method uses ±1st-order laser beams shown in FIG. The ±1st order beams of the laser beams used for the tracking control have a light amount distribution on the reflective surface of the optical disc 4 as shown in FIG. The ±11th order light of the laser beam is diffracted by the information recording track 5 in the portions indicated by the notches in a and b in FIG.
After being reflected by the reflective surface of the disk 4, the light passes through the objective lens 3, is received by the light receiving element of the optical pickup 2, and is converted into an electrical signal. FIG. 5 shows a light receiving element that receives the returned laser beam. 70 is a light receiving element that receives ±1st order light. When the optical disc 4 is tilted, coma aberration occurs in the laser beam spot on the disc surface, so the light intensity distribution on the disc surface changes as shown in Figure 6, and the information recording track causes diffraction. The amounts of light received by the light receiving element 7 change from c and d to c and d, respectively.

However, the output signal of the light receiving element 70 includes not only a component due to the inclination of the disk but also a fluctuation component due to the eccentricity of the information recording track, and this eccentric component (tracking error component) is is 180 Orpm with CAV disc.

Since the CLV disk has a frequency of 60 rpm to 1800 rpm, it is a frequency component of 10 Hz or more.

Therefore, by extracting only the DC component of the output signal of the light receiving element 70, the signal component due to the inclination of the disk can be obtained.

FIG. 1 shows one embodiment of the present invention. Light receiving element 70
The output can be extracted as DC components ic and id in the signal by passing through the low-pass filter 8.

If the operational amplifier 10 performs the operation (io-id),
A disk tilt detection signal can be obtained and further via the driver 11.

By driving the drive means of the mechanism for tilting the optical pickup, in this case the motor 12, the orthogonal relationship between the laser beam optical axis of the optical pickup and the disk surface can be maintained, and the occurrence of coma aberration of the laser spot can be eliminated. , deterioration of the word signal of the recorded information reproducing device can be prevented.

〔Effect of the invention〕

As explained above, according to the present invention, the tilt of the optical disc is detected by using the ±1st-order light of the laser light for tracking signal detection, and the optical axis of the laser beam from the optical big asog is adjusted according to the tilt of the optical disc. Since the structure is configured to control the tilting of the optical disc, even if the optical disc warps due to aging etc.
This has the advantage that it can be read without causing deterioration of the reproduced signal.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is an explanatory diagram showing the main parts of the recorded information reproducing apparatus according to the present invention, and FIG. 3 shows the state of the laser spot on the disk surface. Figure 4 is an explanatory diagram of the light intensity distribution of the ±1st-order laser beam when the disc is not tilted, Figure 5 is an explanatory diagram showing the light receiving element of the optical pickup, and Figure 6 is an explanatory diagram when the disc is tilted. FIG. 3 is an explanatory diagram showing a light amount distribution of laser beams ±1st order light when 2... Optical pickup 3... Objective lens 4... Optical disc 7... Light receiving element 6... ±1st order light of laser light. １″１．゛: “１い・jl、・l”・１、j／、：。

Claims (1)

[Claims] 1. Displacement detection means for irradiating an information recording/reproduction light beam onto a predetermined information track on an information recording disk surface and detecting a predetermined angular deviation between the optical axis of the light beam and the information recording disk surface; In the optical information recording and reproducing apparatus, the optical information recording and reproducing apparatus comprises at least means for adjusting the angle of the optical axis with respect to the information recording disk surface according to the deviation detected, wherein the deviation detecting means detects a tracking error in the tracking error detecting means. An optical information recording/reproducing apparatus comprising a deviation detecting means configured to detect a DC component included in a detection signal and detect the deviation from the DC component.