JPS60251525A - Optical information recorder and reproducing device - Google Patents

Abstract

PURPOSE:To quickly make adjustment of an optical information recorder and reproducing device with a simple mechanism, by providing a transmission type optical wedge which can rotate in a plane vertical to the advancing direction of the 1st optical beam of the reproducing device having two or more light sources in the optical path of the 1st optocal beam. CONSTITUTION:Lights emitting out from a semiconductor laser 2 are changed to parallel lights by a collimator lens 4 and the advancing direction of the parallel lights is slightly changed by a transmission type optical wedge 15. Since the wedge 15 retates in a plane vertical to the incident lights of the optical beam, the direction of lights emitting out from the wedge 15 can be rotated. That is to say, in regard to the optical beam spots image-forming on a photomagnetic disk 9 through an objective lens 8, the spot 22b of a recording and reproducing beam at the center moves in a circle. (The dotted line represents a recorded bit string.) The transmission type optical wedge 15 is adjusted and fixed so that the spot 22b can be superposed upon the recorded bit string when the optical beam spot 22a is put on the right side of the bit string about a half and the spot 22c is put on the left side of the recording spot string about a half.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to improvements in optical information recording and reproducing devices, and particularly to an optical information recording and reproducing device in which the position of a light spot on a recording medium can be easily adjusted.

[Prior art]

Generally, optical disk memories and magneto-optical disk memories are known as recording media for recording and reproducing information using a light beam. In order to discredit the information recorded on these optical disk memories and magneto-optical disk memories, it is necessary to perform tracking control to cause the recording bits to track the light beam spot. For this tracking control, a three-beam method or the like that can detect the left position with high precision is used. In particular, when magneto-optical disk memory is used, the signal component detected using the Kerr effect is weak, making tracking control difficult with the far-field method used for optical disks, and the 3-meter method is difficult. It is valid.

However, in a recording medium with a blurred group, tracking control is required based on the group formed on the recording medium in advance, instead of the recording beep not only during playback but also during recording.

A conventional optical information recording/reproducing apparatus using such a magneto-optical disk memory is shown in FIG. In the figure, 1 is a semiconductor radar with a wavelength λ1 as a light source. 2 is a semiconductor radar with a wavelength λ2 as a light source. 3 and 4 are collimator lenses that convert the light from the semiconductor lasers 1 and 2 into parallel lights, and 5 is a semiconductor laser. A reflective optical wedge that separates the light emitted from 1 into two parallel beams with different inclinations, 6 transmits the light of λ,
This is a beam splitter that inverts the light of λ2 to Fff. The light emitted from the semiconductor radar 2 is a first light beam, and the light emitted from the semiconductor laser l is a second light beam. The three light beams made into the same optical path by the beam splitter 6 are separated by a polarization beam splitter 7 (for example, P polarization transmittance 9
0%, S-polarized light reflectance 98 inches), the light beam emitted from the beam filter 6 is P-polarized and is almost transmitted. It is imaged as a spot. Fifth
The figure shows the state of the light beam spot imaged on the magneto-optical disk 9. In FIG. 5, 21 is a recording bit;
22a and 22c are spots formed by the second light beam having a wavelength of λ, and 22b is a spot formed by the first light beam having a wavelength λ2.

The magneto-optical disk 9 shown in FIG. 4 is rotated by a drive motor 11 via a spindle 10. The magneto-optical disk 9 shown in FIG. magneto-optical disk 9
The polarization direction of the light beam reflected by the polarization beam is rotated by ±θ□ depending on the direction of magnetization, passes through the objective lens 8, and is reflected by the polarization beam sifter 7, so that the apparent Kerr rotation angle is amplified.

This light beam passes through a spherical lens 12 and a polarizing plate 13, and enters detectors 14a, 14b, and 14c. Therefore, the light beams from the light beam spots 22a, 22b, and 22c in FIG.
, 14 b , 14 c are photoelectrically detected. Here, a tracking signal ST is obtained by taking the difference between the output signals of 14a and 14c, and tracking control is performed. Further, focus control is performed using a known method (not shown) using the output signal of the sensor 14b. Further, the light beam forming the light beam spot 22b becomes a recording beam by increasing the power of the semiconductor laser 2 during recording, and becomes a reproduction beam with lower power during reproduction. Therefore, the detector 14b also obtains the reproduced signal SR.

By the way, the width of the recording bit shown in Figure 5 is usually about 1
The diameter of the light beam spot is approximately 1μ.
It is m8 degrees. In order to perform accurate tracking control and obtain a reproduced signal with high intensity and good signal-to-noise ratio, the spot of the recording/reproducing beam overlaps the recording bit string and becomes one of the spots of the tracking control light beam, as shown in Figure 5. The three spots 22a, 22b+22c need to be lined up so that the spot 22a is approximately half on the right side of the recording bit string and the other spot 22c is approximately half on the left side of the recording bit string. However, in the device configuration as shown in Figure 4, 3
two light beams) 22a, 22b.

22c as described above, it is necessary to adjust the angle of the reflective optical wedge 5 or the unit that integrates the semiconductor radars 1 and 2 and the collimator lenses 3 and 4 with high precision within a few seconds of error. The disadvantage is that it is difficult to adjust and takes a long time to adjust.

〔the purpose〕

Therefore, an object of the present invention is to solve the above-mentioned drawbacks.
An object of the present invention is to provide an optical information recording/reproducing device which can easily adjust the positions of three beams in a short time.

〔composition〕

In order to achieve the above object, the present invention includes at least two light sources, irradiates a recording medium with a light beam emitted from the light sources, records and reproduces information on the first light beam, and In an optical information recording and reproducing apparatus that forms at least two or more light beam spots on the recording medium using other different light beams and performs position detection for tracking control; in the optical path of the first light beam; It is characterized in that a transmission type optical wedge is provided which is rotatable in a plane perpendicular to the traveling direction of the first light beam.

〔Example〕

Embodiments of the present invention will be described in detail below based on the drawings.

FIG. 1 is a diagram showing the principle of construction of an optical information recording and reproducing apparatus according to an embodiment of the present invention.The features of this embodiment are that the collimator 1/lens 4 and the beam splitter 6 are different from the conventional example. In between, a transmission type optical wedge 15 is provided to slightly change the angle of the light beam from the semiconductor laser 2. This transmission type optical wedge 15 is provided so as to be rotatable within a plane perpendicular to the optical axis.

Next, the operation of this embodiment will be explained. As shown in FIG. 2, only the light emitted from the semiconductor laser 2 is converted into parallel light by the collimator lens 4, and its traveling direction can be slightly changed by the transmission type optical wedge 15. Since the transmission type optical wedge 15 can rotate within a plane perpendicular to the incident light of the light beam, the direction of the light beam emitted from the transmission type optical wedge 15 can be rotated. The beam of the light beam focused on the magneto-optical disk 9 by the objective lens 8 is as shown in FIG. By doing this, you can draw a circle and move it.

In FIG. 3, dotted lines represent recording bit strings. Then, the transmission type optical wedge 15 is adjusted and fixed so that the spot of 22b overlaps the recording bit string when the spoiler 22a covers about half of the right side of the recording bit string and the optical spoiler 22e covers about half of the left side of the recording bit string.

Although the present embodiment has been described using a magneto-optical disk as the recording medium, it is a matter of course that the present invention is not limited to this and can be applied to other recording media such as optical disks.

〔effect〕

As described above in detail and concretely, according to the present invention, by providing a transmission type wedge, the position of the optical spot for dragging can be adjusted by adjusting the angle of a reflection type optical wedge or a semiconductor laser as in the conventional method. The adjustment mechanism is simple and the adjustment time can be shortened because the adjustment can be replaced with the simple operation of rotating a transmission type optical wedge. An optical information recording/reproducing device that can perform accurate tracking control, has high intensity, and can obtain a reproduced signal with a good signal-to-noise ratio can be obtained with simple adjustment and a short adjustment time.

[Brief explanation of drawings]

1 to 3 relate to one embodiment of the present invention, in which FIG. 1 is a diagram of the configuration principle of an optical information recording and reproducing device, FIG. 2 is an explanatory diagram illustrating the action of a transmission type optical wedge, and FIG. is an explanatory diagram showing the state of the light spot, and FIGS. 4 and 5 relate to the conventional example,
Figure 4 is a diagram of the configuration principle of a conventional optical information recording/reproducing device;
The figure is an explanatory diagram showing the state of the optical strip I2. In the figure, 1.2... semiconductor laser, 9... magneto-optical disk,
15... Chill with a transmission type optical wedge. Figure 1 Figure 2 Figure 1K 3

Claims (1)

[Claims] (1) Provided with at least two light sources, a light beam emitted from the light source is irradiated onto a recording medium, and a first light beam is used to record and reproduce information, and another different light beam is used to record and reproduce information. In an optical information recording/reproducing device that forms at least two or more light beam spots on a medium and performs position detection for tracking control; 1. An optical information recording and reproducing device characterized by being provided with a transmission type optical wedge that is rotatable in a plane perpendicular to .