JP2000242948A - Optical pickup - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an optical pickup which can be made compact and thin with satisfactory productivity while this optical pickup is provided with a tilt adjusting function. SOLUTION: This optical pickup is provided with a light emitting element 17 for emitting laser beams to an optical disk D, a base member 16 for holding the light emitting element 17, a lens holding body 23 having an objective lens 18 for converging the laser beams to the optical disk D, supporting wires 24A, 24B, 25A, and 25B for supporting the lens holding body 23 so that the lens holding body 23 can rock, a suspension base 27 for holding the base terminal sides of the supporting wires whose one part is provided with tilt contact parts 32 and 33 including at least three points of a spherical face, title adjusting columns 21 and 22 erected from the base member 16 which is provided with tilt receiving parts 21A and 22A to be butted to the tilt contact parts, an elastic connecting member 31 for elastically connecting the title adjusting columns with the suspension base so that they can slide, and adjusting members 40 and 41 for adjusting the tilt position of the suspension base. Thus, it is possible to obtain the optical pickup which can be made compact and thin with satisfactory productivity while this optical pickup is provided with a tilt adjusting function.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an optical pickup for recording and reproducing information on a recording medium such as an optical disk.

[0002]

2. Description of the Related Art An optical pickup is known as a device for recording and reproducing information on a recording medium such as an optical disk by using a laser beam. FIG. 10 is a schematic configuration diagram showing such a conventional general optical pickup. This optical pickup has a lens holder 2 for holding an objective lens 1, and this lens holder 2 is fixed upright from a base member 4 by four support wires 3 (only two are shown in the illustrated example). It is swingably supported by the suspension 5. The base member 4 has a light emitting element 6 for generating a laser beam L, and a reflection mirror 7 for reflecting the laser beam L and directing the laser beam L to the optical disk D via the objective lens 1. The entire optical pickup can be moved while being controlled in the radial direction of the optical disk by a moving mechanism (not shown).

At the time of recording / reproducing information on / from the optical disk D, a control current is applied to a focus coil and a tracking coil (not shown) provided on the lens holder 2 via the support wire 3 so that the lens holder 2 is moved in the focus direction (the optical disk direction). Recording and reproduction are performed while making fine adjustments in the track direction. The base member 4 is provided with a permanent magnet (not shown) so as to face each of the coils. Incidentally, it is preferable that the optical axis of the objective lens 1 with respect to the rotating surface of the optical disc D is in a vertically accurate state in order to suppress optical aberration and the like. It is very difficult to ensure the above-mentioned accurate vertical state due to the assembly error of the above. In this case, when the track pitch and the recording density of the optical disc D are not so large, the offset amount with respect to the vertical state is considerably large, so that there is no problem. However, recently, a higher density of recording information is required. Accordingly, a mechanism for adjusting the inclination of the optical axis of the objective lens 1 with respect to the optical disc D, that is, a tilt adjusting mechanism, has been required.

Under such circumstances, a tilt adjusting mechanism 8 as shown in FIG. 11 has been proposed. The tilt adjusting mechanism 8 includes a base member 4 provided with a spherical projection 9 having a downward convex shape and a spherical lower surface, and a second base member accommodating the light emitting element 6 and a reflection mirror below the spherical member. 10 is arranged. Then, the second base member 10
A spherically-perforated receiving portion 12 having a concave-shaped spherical surface 11 provided on the surface thereof.
The lower surface of is set to be slidable. Thus, the inclination of the upper base member 4 is adjusted three-dimensionally by sliding the spherical holed projection 9 to adjust the tilt of the optical pickup.

[0005]

However, in the tilt adjusting mechanism shown in FIG. 11, since the two base members 4, 10 are stacked in two stages, the height H1 of the entire optical pickup is reduced. It becomes considerably large, which is contrary to the demand for miniaturization and weight reduction. There is also a problem that the structure is complicated as a whole, the number of parts is large, and it is not suitable for mass production. The present invention focuses on the above problems, and has been conceived so as to effectively solve the problems. The object of the present invention is to achieve a small size and a thin shape while having a tilt adjusting function, and to improve productivity. It is to provide a simple optical pickup.

[0006]

The invention defined in claim 1 is a light emitting element that emits laser light to an optical disk,
A base member for holding the light emitting element, a lens holder having an objective lens for focusing the laser beam on the optical disk, a support wire for swingably supporting the lens holder, and a base for the support wire. A suspension base having a tilt contact portion holding an end side and partially including at least three spherical points, and a tilt adjustment support having a tilt receiving portion raised from the base member and received in contact with the tilt contact portion An optical coupling member that elastically couples the tilt adjustment column and the suspension base so as to be slidable, and an adjustment member that adjusts a tilt position of the suspension base. As a result, the overall thickness can be reduced and the number of components can be reduced while having a tilt adjusting function.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the optical pickup according to the present invention will be described below in detail with reference to the accompanying drawings. 1 is a plan view showing an optical pickup of the present invention, FIG. 2 is a cross-sectional view taken along the line AA in FIG. 1, FIG. 3 is a right side view of the optical pickup shown in FIG. Perspective view, FIG. 5
FIG. 6 is a view for explaining a curved state between the tilt adjustment support and the tilt contact portion, and FIG. 6 is a view showing a mounted state of the elastic coupling member.
As shown in the figure, the optical pickup 15 has a base member 16 serving as a whole base, and a light emitting element 17 for generating a recording / reproducing laser beam L and an A reflection mirror 19 for reflecting light toward the lens 18 is provided. On the other end side of the base member 16, two tilt adjusting columns 21 and 22, which are features of the present invention, are provided upright.

The objective lens 18 is held by a substantially square lens holder 23, and the reflection mirror 1
The laser beam L reflected from the optical disk 9 is focused and focused on the surface of the optical disk D. A total of four support wires 24A, 24B, 25A, and 25B are connected to the center of both side surfaces of the lens holder 23, and the base ends of the support wires 24A to 25B are:
The lens holder 23 is connected to a suspension base 27 located in a horizontal direction and swingably supported in a horizontal state. The connecting portions of the support wires 24A to 25B to the suspension base 27 include a vibration absorbing member 2 such as a silicone rubber or a gel damping material.
8 intervenes to absorb unnecessary resonance vibration of the lens holder 23. The base end of each of the support wires 24A to 25B is electrically connected to a printed circuit board 29 provided on the back side of the suspension base 27, and the lens holder 23 is connected via the support wires 24A to 25B. A control current is supplied to a focus coil and a tracking coil (not shown) provided in the control circuit.

The suspension base 27 and the two tilt adjusting posts 21 and 22 are elastically slidably slidable by an elastic coupling member 31 composed of a leaf spring as shown in FIG. Are combined. Specifically, on both sides on the rear side of the suspension base 27, there are provided groove-shaped tilt contact portions 32, 33, and the groove-shaped tilt contact portions 32, 33 are provided with the respective tilt adjustment posts. 21 and 22 are loosely fitted and received by the tilt receiving portions 21A and 22A by surface contact. What is characteristic here is that the contact surfaces 32A and 33A of the tilt contact portions 32 and 33 are three-dimensionally formed so as to form a part of a spherical surface having a radius R centered on the center O of the objective lens 18. (See FIGS. 1, 2 and 5).

In the same manner, each of the above-mentioned tilt adjusting columns 21,
The contact surface of the tilt receiving portions 21A, 22A of the 22 is also formed into a three-dimensional curved surface so as to form a part of a spherical surface having a radius R centered on the center O of the objective lens 18. Therefore, the spherical tilt receiving portions 21A, 22A and the contact surfaces 32A, 33A come into sliding contact with each other. As shown in FIG. 6, the elastic coupling member 31 serving as a leaf spring has the groove-shaped tilt adjustment portions 32 on both sides.
Bent holding plates 35 and 36 are formed to be fitted to and clamped at 33, and a center bent holding plate 37 is also formed at the opposite center, and this center bent holding plate 37 is attached to the front side center of the suspension base 27. Into the notch recess 38. By mounting the elastic joining member 31 against the elastic force as shown in FIG. 6, the suspension base 27 and the tilt adjusting posts 21 and 2 are mounted.
2 are slidably and elastically joined. In the actual tilt adjustment, since the adjustment amount is about 2 ° at the maximum, the contact area between the two members is very small.

The base member 16 is provided with two adjusting screws 40 and 41 on the left and right as adjusting members for adjusting the tilt position of the suspension base 27 so as to correspond to both sides of the suspension base 27, respectively. The suspension base 27 can be adjusted in height and in the rotation direction, that is, can be adjusted in tilt.

Next, the operation of the optical pickup configured as described above will be described. First, when the optical pickup 15 is assembled as shown in FIGS. 1 and 2, an assembly error of the optical pickup 15 and an assembly error or a manufacturing error of a rotation system of the optical disc D (a rotation drive system on the main body side of the recording / reproducing apparatus) or the like. If the optical axis of the objective lens 18 and the plane of the optical disk D do not intersect perpendicularly with high precision, tilt adjustment is required. As shown in FIG. 7, for example, when the mounting horizontal level of the objective lens 18 with respect to the lens holder 23 is slightly displaced and it is necessary to tilt the lens holder 23 downward with respect to the front, the base member 16 The suspension base 27 is pushed upward by a small amount by screwing the two adjustment screws 40 and 41 provided at the same amount by the same amount. Then, the spherical contact surfaces 32A, 33A of the tilt contact portions 32, 33 of the suspension base 27 are pushed upward along the spherical surface while being pressed by the respective spherical tilt receiving portions 21A, 22A of the tilt adjusting columns 21, 22. Will move to

In this case, since each spherical surface is a spherical surface centered on the center O of the objective lens 18, the center O of the objective lens 18 does not move and only the optical axis is slightly moved, for example, up to 2 °.
It can be adjusted by moving it. Conversely, when it is desired to move the suspension base 27 downward, the operation reverse to the above, that is, both adjustment screws 40 and 41 may be lowered by the same amount. In this case, if the elastic coupling member 31 is also urged downward with respect to the suspension base 27, the suspension base 27 is moved downward by this resilient force, and the operator can manually move the suspension base 27. The suspension base 27 may be pressed downward.

Further, it is necessary to perform the tilt adjustment by rotating the lens holder 23 leftward in any direction about a central axis 50 (see FIG. 1) along the length direction thereof, for example, as shown in FIG. When there is, the right adjustment screw 41 in FIG. 8 is screwed in by a predetermined amount and protrudes upward, and at the same time, the left adjustment screw 40 in the figure is lowered downward by the same amount. At this time, since a pressing force is applied to the suspension base 27 by an adjuster's hand or by the elastic coupling member 31, the suspension base 27 is rotated leftward by a predetermined angle to perform tilt adjustment. Can be. Also in this case, for the same reason as described above, without moving the center O of the objective lens 18,
Only the optical axis can be rotated. In order to rotate the suspension base 27 in the right direction, a screw operation reverse to that described above may be performed.

Actually, the tilt adjustment is performed by appropriately combining the above two operations. As described above, in this embodiment, the tilt of the objective lens can be adjusted without increasing the thickness of the optical pickup 15, and the size and weight of the objective lens can be reduced. Further, since the number of parts is small and the structure is simple, the mass productivity is excellent. Further, since each of the tilt adjusting posts 21 and 22 is loosely fitted into each of the groove-shaped (recessed) tilt contact portions 32 and 33 of the suspension base 27, the suspension base 27 is placed in a horizontal plane. It does not move more than necessary in the left-right direction and does not shift.

In this embodiment, both the contact surfaces 32A and 33A and the contact surfaces of the tilt receiving portions 21A and 22A which are in contact with the contact surfaces 32A and 33A are formed so as to have a spherical shape with irregularities of the same radius, but the present invention is not limited to this. Alternatively, one of the contact portions or the receiving portions may have a rod-shaped contact portion or a receiving portion structure having a tip including at least three points on a spherical surface.
In this case, for example, a support structure in which three fingers are set upright and a tennis ball is placed thereon is provided, and the same operation and effect as described above can be exhibited. Furthermore,
In the above embodiment, the adjusting screws 40 and 41 are used as the adjusting members as shown in FIG. 8, but instead of this, for example, as shown in FIG. 9, an inclined member 60 having a support surface 60A which becomes an inclined tapered surface. And a corner of the suspension base 27 is supported on the support surface 60A. And
The inclined member 60 is provided with an adjusting knob 62 having a groove 62A.
And the stopper pin 64 standing up therefrom, and by adjusting the rotation angle of the adjustment knob 62, the vertical movement and the rotation amount of the suspension base 27 are adjusted.

[0017]

As described above, according to the optical pickup of the present invention, it is possible to reduce the size and thickness while improving the productivity while having the tilt adjusting function.

[Brief description of the drawings]

FIG. 1 is a plan view showing an optical pickup of the present invention.

FIG. 2 is a cross-sectional view taken along line AA in FIG.

FIG. 3 is a right side view of the optical pickup shown in FIG.

FIG. 4 is a perspective view showing a tilt adjustment support.

FIG. 5 is a diagram illustrating a curved state of a tilt adjustment support and a tilt contact portion.

FIG. 6 is a diagram showing a mounted state of an elastic coupling member.

FIG. 7 is a diagram showing an operation when performing tilt adjustment.

FIG. 8 is a diagram showing an operation when performing tilt adjustment.

FIG. 9 is a view showing a modification of the adjustment member.

FIG. 10 is a schematic configuration diagram showing a conventional general optical pickup.

FIG. 11 is a schematic configuration diagram showing another conventional general optical pickup.

[Explanation of symbols]

15: Optical pickup, 16: Base member, 17: Light emitting element, 18: Objective lens, 21, 22: Tilt adjusting support, 21A, 22A: Tilt receiving portion, 23: Lens holder, 24A, 24B, 25A, 25B ... Support wire, 2
7: suspension base, 31: elastic coupling member, 3
2, 33: tilt contact portion, 32A, 33A: contact surface, 4
0, 41: adjustment screw (adjustment screw member); D: optical disk.

Claims (1)

[Claims] 1. A light emitting element that emits laser light to an optical disk, a base member that holds the light emitting element, a lens holder that has an objective lens that focuses the laser light on the optical disk, and this lens holding A support wire that swingably supports the body, a suspension base that holds a base end side of the support wire and has a tilt contact part including at least three points of a spherical surface in part, and is erected from the base member, A tilt adjusting column having a tilt receiving portion that comes into contact with and receives the tilt contact portion; an elastic coupling member that slidably couples the tilt adjusting column and the suspension base; and a tilt position of the suspension base. An optical pickup comprising: an adjusting member for adjusting.