JPH01166336A - Optical information reader - Google Patents

Abstract

PURPOSE:To eliminate an off-center and to suppress the fluctuation of a tracking error signal amplitude at minimum in the inner and outer circumference of a disk by providing a holding mechanism along the shaft direction of a chilled shaft to hold an optical block, which is held by a guide, to be parallelly movable. CONSTITUTION:A tilt mechanism, which has a sending mechanism to hold an optical system 2, is wholly moved parallelly in the shaft direction of a tilt supporting point 12. Namely, by executing operation to push one of the tilt supporting points 12, which are provided in the both sides of a tilt member with a screw 14 (at such a time, the other supporting point 12 pulls out the screw 14), the tilt mechanism is wholly moved parallelly in the shaft direction of the tilt supporting point 12. Accordingly, a straight line to connect a point, where the optical axis of a reading optical system crosses in the inner circumference of a disk 4, and a point, where the optical axis of the reading optical system 2 crosses in the outer circumference of the disk 4, is adjusted so as to pass through the center of the disk 4. Thus, since the influence of the curvature of a disk track is not received when the reading optical system 2 reads the information of the disk 4, the degradation of an RF signal and a tracking signal, etc., can be prevented.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an optical information reading device equipped with a tilt servo mechanism, and in particular to an optical information reading device that minimizes amplitude fluctuations of tracking error signals in inner and outer tracks of an information recording disk. The present invention relates to an optical information reading device equipped with a mechanism suitable for.

[Conventional technology]

Conventional devices include a feeding mechanism that allows the reading optical system of an optical information reading device to move in the radial direction of the disk, and a reading optical system or reading optical system that allows the optical axis of the reading optical system to enter the disk perpendicularly. Although it is equipped with a tilt mechanism that allows the entire feed mechanism that holds the system to swing, the reading optical system is fixed in the tangential direction of the disk. Note that this type of device is described in, for example, Utility Model Application Publication No. 60-15501.
Publication No. 7, etc. can be mentioned.

[Problem that the invention seeks to solve]

In the above conventional technology, the optical system is located on the inner circumference of the disk, and the optical axis of the optical system is In the above optical system, the @ line connecting two points, the point where the optical system intersects with the Tinuku and the point where the optical system is located on the outer periphery of the Day 2 and the optical axis of the optical system intersects with the Dinuku, does not pass through the center of the disk. There was no consideration given to the off-center position between the disk center and the center of the disk, and the amplitude of the tracking error signal fluctuated in each track from the inner circumference to the outer circumference of the disk, giving rise to a problem in which the tracking servo was affected. .

SUMMARY OF THE INVENTION It is an object of the present invention to provide an optical information reading device that can minimize the fluctuation of the tracking error signal amplitude at the inner and outer circumferences of the disk.

[Means for solving problems]

The above objective can be achieved by providing a mechanism that allows the feeding mechanism that holds the reading optical system of the optical information reading device and the entire tilting mechanism that holds it to be parallel to each other in the axial direction of the fulcrum of the tilting mechanism. be done.

[Effect]

The present invention has the following advantages: By moving the entire feed mechanism that holds the reading optical system of an optical information reading device and the tilt mechanism that holds the feed mechanism in parallel in the axial direction of the fulcrum of the tilt mechanism,
Adjustment can be made so that a straight line connecting the point where the optical axis of the reading optical system intersects at the inner periphery of the disk and the point where the optical axis of the reading optical system intersects at the outer periphery of the disk passes through the center of the disk. Therefore, when reading the information on the optical system disc, the shadow of the curvature of the disc track! Since # is no longer received, the RF double signal tracking signal etc. will not deteriorate.

〔Example〕

Practical examples of the present invention will be described below.

FIG. 2 is a diagram showing a state in which the reading optical system is off-center with respect to the center of the disk, where 1 is an objective lens, 2 is an optical system, 3 is a guide shaft, and 4 is an optical disk. In the figure, when the off-center is set to zero, the center of the objective lens 1 of the reading optical system is It corresponds to the l -1' axis shown in . On the other hand, if the center of the objective lens 1 of the above-mentioned &taking optical system is off-center with respect to the disk center,
-One axis of m' coincides.

When a tracking error signal is obtained using an optical system using a 5-spot method using a diffraction grating, the tracking sub-spot (±1 dimension) is tilted at an angle α shown in Fig. 5 with respect to the disk (/J) rack. irradiated. However, in FIG. 3, 5 is a tracking sub spot and 6 is a reading spot.

If the reading optical system is off-center by ΔX as shown in the second factor, the angle α that the tracking sub-spot makes with respect to the disc track at the inner and outer peripheries of the disc is:
The tracking sub-spot is eclipsed by (ψ - θ) shown in Figure 2, and the way the tracking sub-spot is diffracted by the disc's tracks (bit strings) differs at the inner and outer circumferences of the disk (for each track in a dense manner), and as a result, The tracking error signal amplitude oscillates.

Next, we will explain the device S (that is, the mechanism provided according to the present invention) that moves the feeding mechanism that holds the optical system and the entire tilt mechanism that holds the feeding mechanism in parallel (in the axial direction of the tilt fulcrum). Figure 4 (as shown here, optical system 2
A feed motor (not shown) that transfers the light in the disk radial direction and the entire feed mechanism that holds the connecting member are held by member No. 8, and the optical axis of the optical system 2 is tilted to match the disk 4. In order to make it perpendicular to
It has a tilt mechanism in which the member 8 is rotated by pushing up or pulling down the fulcrum 12 by means of a screw 16 connected to a tilt motor 15 through a connecting member. , 9 is a disk motor, 10
1 is a turntable, 11 is a chilled bearing, 12 is a chilled fulcrum, and 7 is a bearing.

Here, the fulcrum 12 of this tilt mechanism was fixed by a bearing as shown in FIG. 5, a perspective view of the tilt mechanism.

Here, 11 is a tilt bearing, 12 is a tilt fulcrum, and 13 is a set screw. The reason there are two sets is to support the tilt member 8 from both sides. By making this a bearing structure as shown in Fig. 1, one of the fulcrums 12 provided on both sides of the member 8 is pushed by the screw 14 (at this time, the other screw 14 is pulled out). This allows the entire tilt mechanism to be moved in parallel in the axial direction of the tilt fulcrum 12.

〔Effect of the invention〕

According to the present invention, since the off-center amount of the optical system due to the processing accuracy of the member 8 is not a problem, it is possible to obtain the cost reduction effect that the member 8 can be made into an inexpensive pressed product, although it is difficult to achieve accuracy.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing the bottom of an embodiment of the present invention, FIG. 2 is an explanatory view showing the off-center shape 114 of the optical system, and FIG. FIG. 4 is a side view showing the configuration of a conventional optical information reading device, and FIG. 5 is a perspective view showing a conventional tilt fulcrum bearing. 1... Objective lens 2... Optical system 3... Guide shaft 4... Disk 5... Tracking sub spot 7... Bearing 8... Tilt member 9.
...Disc motor 10...Turntable 11
...Tilt bearing 12...Tilt fulcrum 15...
Tilt motor addition 5 H 1 mouth in the figure

Claims (1)

[Claims] 1. A guide that holds an optical block equipped with an optical system for reading information movably along the radial direction of the optical disk, and an axis (chilled axis) in the guide that has an axial direction that intersects the moving direction of the optical block. Centered around
a chill mechanism that rotates the optical block held by a guide to bring it closer to or away from the optical disc surface;
An optical information reading device comprising: a holding mechanism that holds the optical block held by a guide so as to be movable in parallel along the axial direction of the chilled shaft. .