JPH0614247Y2 - Optical pickup position adjustment mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to an optical pickup position adjusting mechanism suitable for a video disc play and a compact disc player, and particularly, a movement locus of the optical pickup passes through a rotation center of a spindle motor. The present invention relates to an optical pickup position adjusting mechanism of a disc player that can be aligned on a straight line.

[Prior Art] An optical pickup such as a video disc player is sent from the inner circumference to the outer circumference of a disc during play.

Conventionally, in order to linearly feed the optical pickup, there has been one in which the optical pickup is guided by a guide rod fixed to a spindle motor and is slid by a feeding mechanism.

[Problems to be Solved by the Invention] However, in the above-mentioned conventional one, although the optical pickup can be sent in a straight line, when the straight line of the movement path of the optical pickup is deviated from the center of the spindle motor, There is a drawback in that the level of the tracking control signal for controlling the tracking mirror differs between the inner circumference and the outer circumference, and accurate tracking cannot be performed on the pit row.

That is, as shown in FIG. 6, the laser beam of the optical pickup causes a main spot for reading the signal of the pit train and side spots E and F for obtaining the tracking control signal, which are shown in FIG. As described above, when the straight line of the movement path of the optical pickup is deviated from the spindle motor center by a distance of Δy, the angle formed by the straight line between the side spot centers and the pit row is Δθ = θ ₁ −θ between the disk inner circumference and outer circumference. _{A difference of 2} = Δy (1 / r ₁ −1 / r ₂ ) is produced. However, r ₁ and r ₂ are the pit row radii of the inside and outside weeks, respectively.

For this reason, the distance between the side spot and the pit row differs between the inner circumference and the outer circumference, and the level of the tracking control signal is different.

The present invention was made in view of the above points,
An object of the invention is to provide an optical pickup position adjusting mechanism which does not cause a difference in the level of the tracking control signal between the inner circumference and the outer circumference of the disc.

[Means for Solving the Problems] An optical pickup position adjusting mechanism of the present invention includes a spindle holder that holds a spindle motor that rotates a turntable, and a guide rod that moves the optical pickup in a radial direction of a disk on which the optical pickup is mounted. In a disc reproducing apparatus having a sub-shash incorporating a pickup feeding mechanism, the sub-chassis is supported by the spindle holder by using an adjusting mechanism capable of moving and adjusting the sub-shash in a horizontal direction perpendicular to the guide rod direction. It is a thing.

[Operation] According to the present invention, the guide rod for guiding the optical pickup and the optical pickup feeding mechanism are incorporated in the sub-chassis, and the sub-chassis can move in parallel to the spindle holder holding the spindle motor. Can be aligned with the center of the spindle motor.

When the straight line of the movement locus of the optical pick passes over the center of the spindle motor, the distance between the side spot and the pit row is the same on the inner circumference and the outer circumference, and there is no difference in the level of the tracking control signal.

[Embodiment] The first embodiment of the optical pickup position adjusting mechanism of the present invention
A description will be given with reference to FIGS.

FIG. 1 is a perspective view showing an embodiment of the present invention.

Reference numeral 5 in the drawing is a spindle motor, which rotates a disk mounted on a turntable 6 fixed to the rotation shaft.

The spindle motor 5 is fastened to a spindle holder 21, and the spindle holder 21 supports the sub-chassis 10 in which the optical pickup 7 is incorporated via left and right brackets 22.

The optical pickup 7 is guided by a guide rod 32 fixed to the sub-chassis 10 and fed by an optical pickup feeding mechanism 9.

The optical pickup feeding mechanism 9 includes a motor 36 and a worm 3.
5. The worm wheel 34 and the pinion 37 are provided. The rack 33 fixed to the optical pickup 7 meshes with the pinion 37, and the optical pickup 7 is sent as the motor 36 rotates.

The support shafts 11, 11 are fixedly planted on the left and right side surfaces of the sub-chassis 10, and the support shafts 11, 11 are tightly fitted in the shaft support grooves 26, 26 provided in the brackets 22, 22 (width W of the shaft support groove W).
Is equal to the diameter of the support shaft 11) The chassis 23 is fastened to the mounting surface 24 of the bracket 22 to close the upper surfaces of the shaft support grooves 26, 26.

That is, the bolts 29, 29 ... Are inserted into the holes 28, 28 ... Provided in the chassis 23, and the bolts 29, 29 ... Are screwed into the female screws 30, 30.

Distance between the base end side surfaces 11a and 11b of the support shafts 11 and 11
₂ is smaller than the distance ₁ between the inner surfaces of the brackets 22 and 22, and the support shafts 11 and 11 are movable only in the width direction, but the axial position is inserted into the support shaft 11 and interposed between the bracket 22 and the side surface of the sub-chassis 10. Then, it is determined by the elastic member 27 for urging the sub-chassis 10 and the screw 40 screwed into the screw 41 to be provided on the bracket 22.

As shown in FIG. 2, the tip portion of the support shaft 11 and the tip taper portion of the screw 40 are in contact with each other, and when the screw 40 moves up and down in the direction of the arrow, the support shaft 11 moves together with the sub-chassis 10 as shown by the arrow. Move axially.

As described above, the sub-chassis 10 is swingably supported by the support shafts 11, 11, but the swing tilt angle is controlled by the tilt mechanism 8 (not shown).

The motor rotates the tilt shaft in response to the detection signal of the tilt sensor 17 attached to the optical pickup 7, and the female screw of the holder is screwed into the male screw of the tilt shaft. Tilt the shash 10.

In this way, the optical pickup 7 keeps a constant distance from the surface of the turntable 6.

Next, a method for adjusting the position of the sub chassis 10 will be described.

As shown in FIG. 4, the side spots E and F on both sides of the main spot M with respect to the pit row of the pitch P are separated by P / 4 above and below the pit row.

Since the sum of the deviations between E and F is P / 2, when the tracking control is stopped and the disc is rotated, the side spots E and F cross a number of pit rows and the output signals of E and F become AC, The phase difference is 180 °.

At that time, the Lissajous waveform becomes a straight line passing through the origin as shown in FIG.

However, when the straight line of the movement path of the optical pickup is deviated from the center of the spindle motor, the angle between the straight line EF and the pit row is different from θ shown in FIG. The sum is not P / 2 but E and F
The output signal has a phase difference of 180 ° + δ, and the Lissajous waveform becomes an ellipse as shown in FIG. 5 (b).

Therefore, by adjusting the screw 40 so that the Lissajous waveform becomes a straight line while observing the Lissajous waveform of the E and F output signals, the movement locus of the optical pickup can be aligned with the center of the spindle motor.

FIG. 3 is a perspective view showing another embodiment of the present invention. In this example, the screw 40 is screwed with the screw provided in the cut-and-raised portion of the chassis 23 so that the tip of the screw 40 contacts the tip of the spindle 11. Contact. In this case, the screw 40 arranged on the shaft of the support shaft 11
The position of the sub chassis is adjusted by.

[Advantage of the Invention] According to the optical pickup position adjusting mechanism of the present invention, since the straight line of the movement path of the optical pickup can be accurately aligned with the center of the spindle motor, there is a difference in the level of the tracking control signal between the inner and outer circumferences of the disc. High-quality reproduction is possible without occurrence of noise.

Further, since the position of the movement locus of the optical pickup can be adjusted, the accuracy of the constituent parts can be lowered and the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention, FIG. 2 is a sectional view showing the same, FIG. 3 is a perspective view showing another embodiment of the present invention, and FIG. 5A and 5B are plan views showing the positional relationship of the laser spots, FIG. 5A and FIG. 5B are Lissajous waveforms showing the optical pickup position adjustment state, and FIG. 6 is a view showing the position of the spot made by the laser beam. FIG. 4 is a diagram showing a positional relationship between a pit row and a laser spot when a straight line of a movement locus of an optical pickup is deviated from the center of a spindle motor. 5 ... Spindle motor, 6 ... Turntable, 7 ...
... optical pickup, 8 ... tilt mechanism, 9 ... optical pickup feed mechanism, 10 ... sub-shash, 11 ... spindle, 16 ... engaging portion, 17 ... tilt sensor, 21 ...
Spindle holder, 22 ... Bracket, 23 ... Chassis, 24 ... Mounting surface, 26 ... Shaft support groove, 27 ... Elastic member, 28 ... Hole, 29 ... Bolt, 30 ... Female thread,
32 ... Guide rod, 33 ... Rack, 34 ... Worm wheel, 35 ... Worm, 36 ... Motor, 3
7 ... Pinion, 40 ... Screw, 41 ... Female thread.

Claims (1)

[Scope of utility model registration request] 1. A disc reproducing apparatus having a sub-chassis incorporating a spindle holder for holding a spindle motor for rotating a turntable, and a pickup feeding mechanism for moving an optical pickup along a guide rod in a radial direction of a disc to be mounted. 2. An optical pickup position adjusting mechanism, wherein the sub-chassis is supported by the spindle holder by using an adjusting mechanism capable of moving and adjusting the sub-chassis in a horizontal direction perpendicular to the guide rod direction.