JPH04195825A - Device for correcting objective lens position for optical pick up - Google Patents

Abstract

PURPOSE:To facilitate alignment of a center of an objective lens and an optical axis of optical pickup by fixing a mount connected with the objective lens to an actuator base by an oblong hole of the mount and a screw piercing through the oblong hole. CONSTITUTION:The oblong hole 6 that is formed along the direction orthogonally crossed with the optical axis of the objective lens 1 is formed within the mount 5 and this mount 5 is fixed to yoke 8 by a screw 11 piercing the oblong hole 6. Then, the mount 5 can be moved in the direction along the oblong hole 6 loosening the screw 11. Thus, the center of the objective lens can be made coincide easily with the optical axis of the light beam by correcting position of the objective lens 1 which is moved along the direction orthogonally crossed with the optical axis.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a device for correcting a positional deviation between the center position of an objective lens and the optical axis of a light beam incident on the objective lens in optical pickup.

[Prior Art] FIG. 3 shows the overall configuration of an actuator portion in a conventional optical pickup, in which (a) is a top view, (b) is a side view, and (c) is a front view.

The objective lens (1) is fixed to the actuator body (12), which is the movable part of the pickup actuator, and the actuator body (12) is fixed to the tips of 514 wires (2), which are a pair of upper and lower pairs and a pair of left and right pairs, which are supporting means. The other ends of the four wires (2) are fixed to the mounting plate (5).

The wire (2) is electrically connected to a tracking coil (3) and a focus coil (10) which are wound around or attached to the actuator body (2), respectively, and the wire (2) is connected to the tracking coil (3) and the focus coil (10), respectively, which are wound around or attached to the actuator body (2). It is supported on a cantilever so that it can move in both directions.

The magnet (4) and yoke (8) that provide driving force to the actuator body (12) are connected to the actuator base (9).
), and the tracking coil (3) and the focus coil (10) are arranged on the left and right sides in FIG.

Further, one of the pair of yokes (8) fixes the mounting plate (5) with screws (11) as shown in the figure.
As a result, the magnet 1-(4), yoke (8), and mounting plate (5) are all supported by the actuator base (9) and constitute a fixed part of the optical pickup, while the objective lens (1) and tracking coil (3) are supported by the actuator base (9). ), the focus coil (10), and the movable part main body (12) constitute the movable part of the optical pickup.

Next, the operation of the conventional pickup actuator will be explained based on FIG.

When a current is passed through the tracking coil (3) wound around the actuator body (12), a force is generated according to Fleming's law, and the actuator body equipped with the cautery lens (1) moves in the vertical direction in Fig. 4(a). move to. Further, when a current is applied to the focus coil (10), the actuator body (12) moves in the vertical direction as shown in FIG. 3(C). In a CD player, the actuator body (12) can also be moved in two directions as described above by a focus servo that keeps the distance between the disc (not shown) and the objective lens (1) constant and a track servo that follows the information track of the disc. to read the recorded information. Since the information track spacing on a CD disc is extremely small at 1.6 μm, tracking in the tracking direction perpendicular to the information tracks requires only the lightweight actuator body (12) to be driven;
12) Moved a certain distance +1. +1, the system is such that the actuator base (9) itself, that is, the entire pickup, also moves.

[Problems to be Solved by the Invention] In the conventional pickup described above, if the amount of deviation between the center of the objective lens (1) attached to the actuator body (12) and the optical axis is 20011 m,
The follow-up performance of the actuator is degraded by the amount of deviation, and the optical characteristics are not used in the best condition.

Therefore, until now, the accuracy of each part was specified as high precision,
During assembly, efforts have been made to improve the precision of jigs and other tools to align the optical axis and the center of the objective lens as much as possible, but there are naturally limits to improving component precision and jig viscosity, and adjustments are necessary. There were issues with mass production, such as increasing assembly work efficiency and identifying defects for the first time through inspection after assembly was completed.

Purpose of the Invention The present invention has been made to solve the above-mentioned problems, and provides a pickup that can easily correct the deviation m between the optical axis and the midpoint position of the objective lens and has improved tracking performance. The purpose is to provide the following.

[Means for Solving the Problems] In the objective lens position correction device according to the present invention, a support means for swingably supporting the objective lens is supported by a pickup base via a mounting plate, and the mounting plate is attached to the objective lens. It has a long hole in a direction perpendicular to the optical axis of the actuator, and is fixed to the actuator base with a screw passing through the long hole.

Further, the mounting plate is fixed to the actuator base via a spring.

"Operation" In the above configuration, by loosening the screw and moving the mounting plate) in the direction along the elongated hole, the objective lens is moved in a direction perpendicular to the optical axis and the position is corrected. The optical axis of the light beam can be made to coincide with the optical axis.

Furthermore, since a spring is present, by adjusting the degree of threading of the screw, the objective lens can be moved in a direction perpendicular to the moving direction of the mounting plate and perpendicular to the optical axis direction. Therefore, the objective lens is positioned at the correct position hO in two directions perpendicular to the optical axis.

[Example] An example of the present invention will be described based on the drawings. Figure 1 shows
The structure of the optical pickup according to this embodiment is shown, in which (a) is a plan view, (b') is a side view, and (c) is a front view. FIG. 2 is an overall view of a pickup carriage in which an optical pickup is shown.

In the optical pickup of this embodiment, the drive structure of the actuator main body including the objective lens is completely the same as that of the conventional example shown in FIG. 3, so the same parts are given the same reference numerals and detailed explanation will be omitted.

A feature of this embodiment is the means for supporting the actuator body (12). A mounting plate (5) that fixes the wire and an actuator base (9) of this mounting plate (5).
) in the mounting structure.

That is, as can be seen from FIGS. 1(a) and (b), the mounting plate (5) is formed with a long hole (6) extending in a direction perpendicular to the optical axis of the objective lens (]). The plate (5) is fixed to the yoke (8) by screws (11) passing through the elongated holes (6).

Further, a spring (7) is interposed between the mounting plate (5) and the yoke (8).

In addition, in Fig. 2, (13) is the pickup base,
(14) is an ALPC circuit section.

Next, the operation of correcting the position of the objective lens will be explained with reference to FIGS. 1 and 2.

First, the correction in the radial direction shown in FIG. 2 is performed as follows. Loosen the screw (1) and slide the mounting plate (5) that supports the wire (2) along the long hole (6), and the objective lens (1) will align with the optical axis along with the mounting plate (5). It moves in the orthogonal radial direction (vertical direction in FIG. 1(a)). This allows the optical axis of the light beam incident on the objective lens (1) to coincide with the center of the objective lens (1) in the radial direction.

The one-way jitter correction shown in FIG. 2 is performed by adjusting the screwing position of the screw (11).

In other words, if you loosen the screw (11), you can remove one plate (
The objective lens (]) integrated with 5) moves toward the front in FIG. 1(a) due to the elastic force of the spring (7), and moves to the left when tightened. This direction of movement is perpendicular to both the optical axis and the radial direction described above, and is the jitter direction, which is the direction of the information tracks on the disk. Therefore, the center of the objective lens (1) is adjusted in the direction of the optical axis.

Therefore, the screw (11) is used to adjust the position of the objective lens in two directions and to fix the mounting plate (5).

[Effects of the Invention] As described above, according to the present invention, the mounting plate connected to the objective lens is fixed to the actuator base by the long holes of the mounting plate and the screws passing through the long holes. The optical axis of the optical pickup and the center of the objective lens can be aligned with the container, which improves the performance of the optical pickup and improves the yield. This has the effect that it is not necessary to design used equipment with high precision.

[Brief explanation of the drawing]

FIG. 1 is an overall view of an optical pickup according to an embodiment of the present invention, FIG. 2 is an overall view of a carriage on which the optical pickup is mounted, and FIG. 3 is an overall view of a conventional optical pickup. In the figure, (1) is the objective lens, (2) is the wire, (
3) is a tracking coil, (4) is a magnet, (
5) is the mounting plate, (6) is the long hole, (7) is the spring, (8) is the yoke, (9) is the actuator base,
(10) is a focus coil, 01) is a screw, (12)
is the actuator body, (13) is the pickup base, and (14) is the ALPC circuit. Note that the same reference numerals in each figure refer to the same or corresponding parts.

Claims (1)

[Claims] The actuator body includes an objective lens and a supporting means that swingably supports the actuator body, and a light beam that is irradiated onto an information track on an optical disk through the objective lens tracks the information track, thereby optically transmitting information. In the optical pickup for optical reading, the support means is supported by the actuator base via a mounting plate, and the mounting plate is formed with a long hole extending in a direction perpendicular to the optical axis of the objective lens. 1. A position correcting device for an objective lens in an optical pickup, characterized in that a mounting plate is screwed onto an actuator base with a screw passing through the actuator base.