JPH04209332A - Objective lens supporting device - Google Patents

Abstract

PURPOSE:To miniaturize the supporting body for lens drive by forming a fixing plate engagement part fixing a fixing plate to a base by engaging a base side engagement part provided on a base on a lens retainer connecting plate side position of the fixed plate. CONSTITUTION:The connecting member 12 of the supporting body for lens drive 1 is made variable in the vertical direction against the fixing plate 7 fixed to the base 3 with the effect of a parallel link constituted by an upper horizontal plate 4, a lower horizontal plate 5, a lens retaining connection plate 6, the fixing plate 7, and hinge parts 8 to 11. An objective lens 13 of a lens retaining body 2 connected with the member 12 is movable in the vertical direction against the base 3. A rotating part 12b of the member 12 can be rotated in a horizontal direction against a fixing part 12a, that is the base 3. Because the supporting body 1 is fixed to the base 3 by piercing a fixing shaft 23 through a shaft piercing hole 7b of a connection piece 7a, the device can be miniaturized.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an objective lens support device used for optical pickup in an optical information recording/reproducing device such as an optical disk player.

[Conventional technology]

Conventionally, optical information recording/reproducing devices such as optical disc players are equipped with an optical pickup device. This type of optical pink-up device records signals on an optical disk by focusing a light beam generated by a light beam generating means such as a semiconductor laser onto the recording surface of the optical disk as a focused spot with a predetermined diameter using an objective lens. , erasing, and detecting signals from the optical disc. Therefore, in order to perform these operations with high precision, the distance between the objective lens and the recording surface of the optical disk must be adjusted without being affected by the unevenness of the recording surface of the optical disk or the accuracy of the spindle mechanism on which the optical disk is mounted. It must always be kept constant. Furthermore, it is necessary to ensure that the above-mentioned focused spot does not deviate from the recording track on the recording surface of the optical disc. Therefore, the conventional optical pickup device includes an objective lens support device that supports the objective lens so as to be movable in the direction of its optical axis, that is, the focusing direction, and in the direction orthogonal to this direction, that is, the tracking direction. ing.

This type of objective lens support device is disclosed in Japanese Patent Application Laid-Open No. 62-4062.
As also disclosed in Japanese Patent No. 7, the hinge parts 51 to 54 and the hinge parts 51 to 54 as shown in FIG.
A lens driving support 59 has a parallel link consisting of an upper horizontal plate 55, a lower horizontal plate 56, a lens holder connecting plate 57, and a fixing plate 58, which are connected to each other so that the vertical cross section becomes a parallelogram. We are prepared.

The lens driving support 59 has a rotating portion 61 provided on the lens holder connecting plate 57 via a hinge portion 60.
Opening 6 of lens holder 63 that holds objective lens 62
The fixing shaft 66 erected on the base 65 is inserted into the shaft insertion hole 58a of the fixing plate 58, and the fixing shaft 66 is inserted into the shaft insertion hole 58a of the fixing plate 58.
Two boss portions 58b, 58b formed on the lower surface of the base 65 are fitted into fixing holes 65a, 65a of the base 65. Thereby, the lens holder 63 is supported by the base 65 via the lens driving support 59 so as to be movable in the X direction and the Y direction. Then, the objective lens 6 of the lens holder 63
2 includes a focus coil 66 provided on both sides of the lens holder 63, radial coils 67, and a base 65.
Yoke plates 68 and 69 and magnet 22 provided in
The magnetic circuit is configured to be driven in the Y direction, that is, the focusing direction, and in the X direction, that is, the tracking direction.

[Problem to be solved by the invention]

However, in the above conventional structure, the lens driving support 5
A shaft insertion hole 58a is formed in the fixing plate 58 of No. 9, and the fixing shaft 66 of the base 65 is inserted into the fixing hole 58a of the fixing plate 58.
5a and 65a, the lens driving support 1 is fixed to the base 65. Therefore, the fixing plate 58 needs to be thick enough to form the shaft insertion hole 58a. This has the problem that the lens drive support 59, that is, the objective lens support device, has to be made thicker, which increases the size of the lens drive support 59, that is, the objective lens support device.

[Means for Solving the Problems] In order to solve the above problems, the objective lens support device of the present invention includes a fixing plate, a lens holder connecting plate facing the fixing plate, and a connecting plate disposed between these plates. A fixing plate formed on the above-mentioned fixing plate, comprising a lens driving support body in which the two plates are connected via a hinge so as to form a parallelogram, thereby forming a parallel link. The fixing plate is fixed to the base by the side engaging part engaging with the base side engaging part formed on the base, and the lens holder connecting plate is connected to the lens holder that holds the objective lens. In this objective lens support device, the objective lens can be moved in the focus direction by displacement of the parallel link with respect to the base, and the following measures are taken.

That is, the above-mentioned fixing plate side engaging portion is formed on the lens holder connecting plate side portion of the fixing plate.

(Function) According to the above configuration, the fixing plate side engaging part for fixing the fixing plate to the base by engaging with the base side engaging part formed on the base is fixed to the lens of the fixing plate. Since it is formed on the holder connecting plate side, if the fixing plate side engaging part is provided on the opposite side of the fixing plate from the lens holder connecting plate side, or if the fixing plate is installed inside the fixing plate. Compared to the case where a side engaging part is formed, the thickness of the fixing plate including the fixing plate side engaging part on the side opposite to the lens holder connecting plate side can be made thinner, which allows the lens drive The support body for this purpose is reduced in size.

[Example] An example of the present invention will be described below based on FIGS. 1 and 2. For convenience of explanation, lens driving support 1
The lens holder connecting plate 6 side is the front, the fixing plate 7 side is the rear, the upper horizontal plate 4 side is the top, and the lower horizontal plate 5 side is the bottom.

As shown in FIG. 1, the optical pickup includes a lens drive support 1, a lens holder 2, and a base 3. The lens driving support 1 is made of, for example, a soft synthetic resin material, and has an upper horizontal plate 4 and a lower horizontal plate 5 having a trapezoidal longitudinal section and arranged vertically in parallel. Hinge portions 8 and 9 are provided at the front edges of the upper horizontal plate 4 and the lower horizontal plate 5.
The upper and lower edges of the lens holder connecting plate 6 are connected through the hinges 0 and 11, and similarly, the rear edges of the upper horizontal plate 4 and the lower horizontal plate 5 are fixed through the hinge parts 0 and 11. The upper and lower edges of the plate 7 are connected. That is, the upper horizontal plate 4, the lower horizontal plate 5, the lens holder connecting plate 6, and the fixing plate 7 are connected at the hinge parts 8 to 11 so that the vertical cross section forms a parallelogram, thereby forming a parallel link. is configured.

A curved concave notch 4a is formed at the center of the rear edge of the upper horizontal plate 4, and a notch 4a is formed at the center of the upper edge of the fixing plate 7, extending in the direction of the upper horizontal plate 4. A connecting piece 7a which is a curved convex fixed plate side engaging part corresponding to the notch 4a of the plate 4 is formed. The connecting piece 7a is formed to be slightly smaller than the inner diameter of the notch 4a so that the upper horizontal plate 4 can rotate relative to the fixed plate 7 without being restricted by the connecting piece 7a. A shaft insertion hole 7b for inserting a fixed shaft 23, which will be described later, is formed in the connecting piece 7a. Although not shown in the figure, the above-described notch 4a and connecting piece 7a are also formed at the rear edge of the lower horizontal plate 5 and the lower edge of the fixed plate 7. Furthermore, two boss portions 7C and 7c are formed on the lower surface of the fixing plate 7 to be fitted into fixing holes 3a and 3a' in the base 3, which will be described later.

Further, a connecting member 12 is provided on the side surface of the lens holder connecting plate 6 facing the fixing plate 7. This connecting member 12 is provided in parallel with a fixed part 12a fixed to the lens holder connecting plate 6 and the lens holder connecting plate 6,
A plate-shaped rotating portion 12b that extends in the width direction of the upper and lower horizontal plates 4 and 5 and projects laterally from the upper and lower horizontal plates 4 and 5, and a plate-shaped rotating portion 12b that can be horizontally rotated. , the rotating part 12
12C of hinge parts which connect the center part of b with the fixing|fixed part 12a.

The lens holder 2 is provided with an objective lens 13 on the upper surface of the front part. Further, in the recesses 14 formed on both sides of the central part of the lens holder 2, a focus coil 15 for moving the objective lens 12 in the vertical direction and a radial coil for moving the objective lens 13 in the horizontal direction are provided. 16
・16 are provided respectively. These focus coils 15 and radial coils 16 are connected to an external circuit board (not shown) via connection leads 17.

An opening for arranging the lens driving support 1 is formed in the lens holder 2 from behind the objective lens 13 to the rear end thereof. This opening 18 is formed to a size that takes into consideration the deformation range of the lens driving support 1. Connecting grooves 18a, 18a are formed on both sides near the center of the opening 18, into which both ends of the rotating portion 12b of the connecting member 2 of the lens driving support 1 are fitted and fixed. Further, a counterweight 24 is provided on the rear end surface of the lens holder 2.

An opening 19 is formed in the center of the base 3, and a pair of yoke plates 20 forming a yoke are provided on both sides of this opening.
21 are erected on the inside and outside at a predetermined interval. A plate-shaped magnetite 22 is provided on the side surface of each outer yoke plate 21 facing the yoke plate 20.

Further, in the center of the base 3 near the rear end, there is a fixed shaft 23 as a base-side engaging portion that is inserted into the shaft insertion hole 7b of the connecting piece 7a in the fixed plate 7 of the lens driving support 1. The boss portion 7 of the fixing plate 7 is provided on both sides of the fixing shaft 23.
Fixing holes 3a and 3a are formed for inserting the fixing holes 3a and 7c.

Then, both ends of the connecting member 12 of the lens driving support 1 are arranged in the connecting grooves 18a and 18a in the opening 18 of the lens holder 2, and the lens driving support 1 and the lens holder 2 are connected to each other. At the same time, the fixed shaft 23 of the base 3 is inserted into the shaft insertion hole 7b of the connecting piece 7a in the fixed plate 7 of the lens driving support 1, and the boss portions 7c and 7C of the fixed plate 7 are inserted into the shaft insertion hole 7b of the connecting piece 7a of the fixed plate 7 of the lens driving support 1. By fitting into the fixing holes 3a, the lens holder 2 is movably supported by the base 3 via the lens driving support 1. At this time, each yoke plate 20 is inserted into the corresponding focus coil 15,
The radial coil 16 faces the magnet 22 with a predetermined distance therebetween.

In the above configuration, first, the displacement operation of the lens holder 2, that is, the objective lens 13, by the lens driving support 1 will be explained.

The connecting member 12 of the lens driving support 1 is formed by the action of a parallel link composed of an upper horizontal plate 4, a lower horizontal plate 5, a lens holder connecting plate 6, a fixing plate 7, and hinge parts 8 to 1. It is movable in the vertical direction with respect to a fixed plate 7 fixed to the base 3. Therefore, the objective lens 13 of the lens holder 2 connected to the above-mentioned connecting member 12 can be moved up and down with respect to the base 3. In addition, the rotating portion 12 of the connecting member 12
b is rotatable in the horizontal direction with respect to the fixed part 12a and the base 3; Therefore, the objective lens 13 of the lens holder 2 connected to the rotating part 12b can be rotated in the horizontal direction with respect to the base 3. As a result, the objective lens 13 is driven by the focus coils 15, radial coils 16, . and can be displaced in the X direction, that is, in the tracking direction.

In addition, in this objective lens support device, the lens drive support 1 has the fixed shaft 23 inserted into the shaft insertion hole 7b of the connecting piece 7a extending from the fixed plate 7 in the upper horizontal plate 4 direction and the lower horizontal plate 5 direction. Since the fixing plate 7 is fixed to the base 3 by being fixed to the base 3 by being
Since it is fixed to the base 3 by the fixed shaft 23, compared to the fixed plate 58 through which the fixed shaft 66 of the objective lens support device shown in FIG. In addition, the thickness of the fixed plate 7 is reduced by the thickness A. Therefore, the length of the objective lens support device as a whole in the front-rear direction can be reduced by an amount corresponding to the above-mentioned thickness A, and the device can be made smaller by that amount. Furthermore, in this embodiment, the connection between the connecting piece 7a and the fixed shaft 23 is as follows.
Upper horizontal plate 4, lower horizontal plate 5, lens holder connecting plate 6, fixing plate 7
Since this is done within the parallel link consisting of the hinge parts 8 to 11, there is almost no protrusion of the member for connection to the outside of the parallel link, and further miniaturization is possible.

〔Effect of the invention〕

As described above, in the objective lens support device of the present invention, the fixing plate side engaging part for fixing the fixing plate to the base by engaging with the base side engaging part formed on the base is fixed. This configuration is formed on the lens holder connecting plate side portion of the plate.

As a result, if the fixing plate side engaging part is provided on the opposite side of the fixing plate from the lens holder connecting plate side, or if the fixing plate side engaging part is formed inside the fixing plate. Compared to this, the thickness of the fixing plate including the fixing plate side engaging portion on the side opposite to the lens holder connecting plate side can be made thinner. Therefore, it is possible to reduce the size of the lens drive support, that is, the objective lens support device.

[Brief explanation of the drawing]

1 and 2 show one embodiment of the present invention. FIG. 1 is an exploded perspective view showing the objective lens support device. FIG. 2 is a schematic plan view used to compare the sizes of the objective lens support device shown in FIG. 1 and the objective lens support device shown in FIG. 3. FIG. 3 shows a conventional example, and is an exploded perspective view showing an objective lens support device. 1 is a support for lens driving, 2 is a lens holder, 3 is a base, 4 is an upper horizontal plate, 5 is a lower horizontal plate, 6 is a lens holder connecting plate,
7 is a fixed plate, 7a is a connecting piece (fixed plate side engagement part), 8 to 1
1 is a hinge part, 12 is a connecting member, 12b is a rotating part, 12
Reference numeral c represents a hinge portion, 13 represents an objective lens, and 23 represents a fixed shaft (base side engaging portion). Patent applicant Sharp Co., Ltd. Figure 2

Claims (1)

[Claims] 1. A fixing plate, a lens holder connecting plate facing the fixing plate, and two plates disposed between these plates are arranged via a hinge so that they form a parallelogram. The lens drive support body is connected to each other to form a parallel link, and the fixing plate-side engaging portion formed on the fixing plate engages with the base-side engaging portion formed on the base. By aligning the fixing plate with the base, the lens holder connecting plate is connected with the lens holder that holds the objective lens, and the displacement of the parallel link with respect to the base moves the objective lens in the focus direction. A movable objective lens support device, characterized in that the above-mentioned fixing plate side engaging portion is formed at a portion of the fixing plate on the lens holder connecting plate side.