JPH0450563Y2 - - Google Patents

Description

[Detailed explanation of the idea] The present invention will be explained in the following order.

A. Field of industrial application B. Overview of the invention C. Conventional technology D. Problem that the invention attempts to solve E. Means for solving the problem F. Effect G. Example G-1 Overall configuration (Figs. 2 and 3) ) G-2 Installation of the two-axis drive unit (Fig. 1,
Figure 4) H Effect of the invention A Industrial application field The present invention is an optical head for a disk player that makes a light beam incident on a disk through an objective lens and performs focus control and tracking control for the light beam incident on the disk. Regarding equipment.

B. Summary of the invention This invention supports an objective lens so that it can be displaced in a direction along its optical axis and in a direction orthogonal thereto, allows a light beam to enter a disk through the objective lens, and focuses the light beam incident on the disk. In an optical head device for a disk player that performs control and tracking control, a substrate member to which a lens support member that can swing and hold an objective lens is attached is connected to a spherical shaft portion and a spherical bearing portion. A connecting member consisting of a connecting rod fixed to the base plate member or the movable base member through the engaging portion of the connecting rod, a cap nut screwed onto the connecting rod, and a coil spring disposed between the connecting rod and the connecting rod. Therefore, the substrate member is biased toward the movable base member, the cap nut is loosened relative to the connecting rod, the coil spring is extended, and the inclination of the objective lens is adjusted by the inclination adjusting screw that connects the substrate member and the movable base member. The base member is fixed to the movable base member by adjusting the corner, and after the adjustment is completed, the cap nut is tightened against the connecting rod and the coil spring is compressed, and the adjusted objective is fixed to the movable base member. By maintaining the tilt angle of the lens, the tilt angle of the objective lens can be efficiently adjusted, and the tilt angle of the objective lens does not change after adjustment.

C. Prior Art An optical disk player that reproduces information from a disk-shaped recording medium is equipped with an optical head device that constitutes an optical system for reading information from recording tracks formed on the disk-shaped recording medium.

In such an optical head device, for example, as shown in a simplified manner in FIG. be able to move along a direction. Then, the laser beam emitted from the semiconductor laser 61 is diffracted by the grating 62 into three laser beams (in FIG. 5, for simplicity, these three laser beams are ), its optical axis direction is changed by a polarizing beam splitter 63 and the beam enters a collimator lens 64 . The laser light beam collimated by the collimator lens 64 is made incident on the disk D through the objective lens 66, is modulated by the recording track formed on the disk D, and is reflected.

The reflected laser beam from the disk D passes through the objective lens 66 and the collimator lens 64 in order and returns, passes through the polarizing beam splitter 63 without changing its optical axis direction, and passes through the light receiving lens (concave lens) 68. The light is then guided to a photodetector 70.
The detection output obtained from this photodetector 70 is then supplied to a signal processing section (not shown),
A reproduction information signal, a focus control signal and a tracking control signal are formed. The focus control signal and the tracking control signal are supplied to a focus control drive unit 71 and a tracking control drive unit 72, respectively, which are arranged in relation to the objective lens 66, thereby aligning the objective lens 66 with its optical axis. A driving operation for focus control is performed to move the objective lens 66 toward or away from the disk D along the optical axis, and at the same time, the objective lens 66 is moved in the radial direction of the disk D, which is a direction perpendicular to its optical axis. A driving operation for tracking control is performed.

In an optical head device that operates as described above, a mechanism (hereinafter referred to as
It has been proposed to construct a two-axis drive unit (referred to as a two-axis drive unit) into one block, and to attach this two-axis drive unit to a movable base member that can be moved along the radial direction of the disk. FIGS. 6 and 7 show an example of an optical head device having such a configuration.

In the optical head device shown in FIGS. 6 and 7, a biaxial drive unit 20 (however, the outer case is removed) is attached to the upper surface side of the movable base member 18. The two-axis drive unit 20 includes a magnetic yoke member 2 made of a magnetic plate member.
4, and this magnetic yoke 24 is attached to the substrate member 22 with screws 23. The magnetic yoke member 24 is provided with two sets of opposing bent erected pieces 28a and 28b, and each bent erected piece 2
A magnet 30 is fixed to 8a. And, by the bent standing pieces 28a and 28b and the magnet 30,
A magnetic field forming section is formed which constitutes a focus control drive section and a tracking control drive section together with a focus control coil and a tracking control coil, which will be described later. The magnetic yoke member 24 also includes a bobbin member 48 that holds the objective lens 66.
is attached via a hinge member 38. In this example, a lens support member is constituted by the bobbin member 48, the hinge member 38, etc., and the objective lens 66 is kept approximately horizontal with respect to the substrate member 22, and the lens support member, the magnetic yoke member 24, and the substrate A biaxial drive unit 20 includes the member 22.

The hinge member 38 is connected to the mounting portion 43 and the mounting portion 4.
3 and a parallel arm part 42 connected to the bobbin member 48 via a hinge part, and the objective lens 66 attached to the bobbin member 48 can be moved in a direction along the optical axis and in a direction perpendicular thereto. There is. On the other hand, a pair of cylindrically wound focus control coils 54 are attached to the bobbin member 48, and the magnet 30 of the focus control coils 54 is attached to the bobbin member 48.
A tracking control coil 5 is mounted on the side facing the
5, the direction of the winding axis is the focus control coil 5
4 and are insulated and closely attached so as to be orthogonal to the direction of the winding axis. A flexible connection board 5 is provided on the upper end surface of the bobbin member 48 for connecting the focus control coil 54 and the tracking control coil 55 to a focus control signal supply section and a tracking control signal supply section, respectively.
8 is fixed at one end. The other end of the flexible connection board 58 is led to the lower surface of the bobbin member 48 through a notch formed in the center of the bobbin member 48, and further led out to the outer surface of the hinge member 38 through the lower surface of the hinge member 38. There is. In addition, through holes 22a and 18a forming an optical path are formed in portions of the substrate member 22 and the movable base member 18 corresponding to directly below the objective lens 66.

Under such a configuration, when a focus control signal is supplied from the focus control signal supply section to the focus control coil 54 through the flexible connection board 58, each of the pair of focus control coils 54 is formed by the above-described magnetic field forming section. In the magnetic field generated, the objective lens 66 receives an electromagnetic force in a direction along the optical axis. Therefore, the bobbin member 48 to which the focus control coil 54 is fixed is attached to the objective lens 66 by the parallel arm portion 42 of the hinge member 38.
is moved in the direction along the optical axis of the
The objective lens 66 is moved in a direction along its optical axis in response to the focus control signal.

Furthermore, when a tracking control signal is supplied from the tracking control signal supply section to the tracking control coil 55 through the flexible connection board 58, one of the tracking control coils 55 is activated in the magnetic field formed by the above-mentioned magnetic field forming section. One receives an electromagnetic force that causes one to be brought close to the magnet 30 facing it, and the other to be moved away from the magnet 30 facing it. As a result, the tracking control coil 55 is fixed to the bobbin member 48 via the focus control coil 54.
is rotated about the hinge portion 44 of the hinge member 38 as a pivot point, and as a result, the objective lens 66 is moved in a direction perpendicular to its optical axis in accordance with the tracking control signal.

When the biaxial drive unit 20 configured in this manner is attached to the movable base member 18, it is necessary to adjust the inclination angle of the objective lens 66. In order to make such adjustment, in the example shown in FIGS. 6 and 7, a spherical shaft portion 45 is provided on the lower surface of the substrate member 22, and a spherical shaft portion 45 is provided on the upper surface of the movable base member 18. A bearing portion 46 is provided, and the substrate member 22 is stacked on the movable base member 18 with its spherical shaft portion 45 engaged with the spherical bearing portion 46 of the movable base member 18 . Further, female screw portions 25 and 26 are formed on the substrate member 22, and a female screw portion 27 is formed approximately on the orthogonal bisector Q of the line segment P connecting the female screw portions 25 and 26. Ru. A washer 31 and a coil spring 3 are attached to the female screw portion 27.
The connecting rod 37 to which the movable base member 18 is attached is screwed through a through hole 39 provided in the movable base member 18. As a result, the entire biaxial drive unit 20 is urged toward the movable base member 18. Further, inclination adjustment screws 35 and 36 are screwed into the female screw portions 25 and 26, respectively, through through holes 40 and 41 formed in the movable base member 18. Then, by screwing in or unscrewing the inclination adjustment screws 35 and 36, the spherical shaft portion 45 of the base plate member 22 is guided by the spherical bearing portion 46 of the movable base member 18 and is displaced, thereby driving the two-axis drive. The entire unit 20 is rotated on the spherical bearing 46 to adjust the tilt angle of the objective lens 66. With such adjustments made, attachment of the two-axis drive unit 20 to the movable base member 18 is completed.

D. Problems to be solved by the invention As described above, the biaxial drive unit 20 is attached to the movable base member 18, and the objective lens 6 is attached to the movable base member 18.
In an optical head device in which the tilt angle is adjusted as shown in Fig. 6, if the elasticity of the coil spring 32 attached to the connecting rod 37 is not set to be sufficiently large, the movable base may be damaged by a slight shock or vibration. The mounting angle of the substrate member 22 with respect to the member 18 changes, and therefore the inclination angle of the objective lens 66 changes. For this reason, the objective lens 66
In order to prevent changes in the inclination angle of the coil spring 32, it is desirable that the elasticity of the coil spring 32 is set to be sufficiently large. However, if the elasticity of the coil spring 32 is set to be sufficiently large, 20 to the movable base member 18 and the task of adjusting the inclination angle of the objective lens 66 cannot be performed efficiently.

In addition, in order to avoid such problems, the objective lens 6
After adjusting the tilt angle of the objective lens 66, the biaxial drive unit 20 is fixed to the movable base member 18 using adhesive or the like, and the tilt angle of the objective lens 66, which has been adjusted once, can be corrected or readjusted. This results in the inconvenience of being unable to perform the task.

In view of these points, the present invention provides a lens support member that holds an objective lens and is movable in a direction along the optical axis of the objective lens and a direction orthogonal thereto, a magnetic yoke member disposed in relation to the lens support member, and a magnetic yoke member arranged in relation to the lens support member. It is possible to easily and efficiently attach the biaxial drive unit assembled as one block consisting of substrate members, etc. to the movable base member and adjust the tilt angle of the objective lens. An object of the present invention is to provide an optical head device for a disk player that can prevent changes in the tilt angle of an objective lens and also allow readjustment.

E. Means for Solving the Problems In order to achieve the above-mentioned object, the optical head device for a disk player according to the present invention holds an objective lens, and is equipped with a focus control coil and a tracking control coil, and the objective lens is attached to the optical head device. A lens support member that is movable to be displaced in a first direction along the optical axis and a second direction perpendicular to the optical axis; an upper surface portion to which the lens support member is attached; and a lower surface provided with a spherical shaft portion. a movable base member provided with a spherical bearing portion that engages with the spherical shaft portion of the substrate member; the substrate member is coupled to the movable base member, and the inclination angle of the objective lens can be adjusted. a pair of tilt adjustment screws, and a connecting member having a fixing portion that is positioned on or near the orthogonal bisector of a line segment connecting the tilt adjustment screws and is fixed to the substrate member or the movable base member; The connecting member is provided with a connecting rod having a threaded portion formed on an end side remote from the fixing portion, a cap nut that is screwed into the threaded portion of the connecting rod, and a connecting member disposed between the connecting rod and the cap nut. , a coil spring that biases the substrate member toward the movable base member, and when the cap nut is loosened from the threaded portion and the coil spring is expanded, the objective is adjusted by screwing in the tilt adjustment screw. A state in which the tilt angle of the lens is adjusted, and the adjusted tilt angle of the objective lens is maintained by tightening the cap nut against the threaded portion and compressing the coil spring. shall be taken.

F. Effect In the optical head device for a disk player according to the present invention configured as described above, when the substrate member to which the lens support member is attached is attached to the movable base member, the bag that is screwed onto the connecting rod is attached. The nut is in a loosened state, that is, a gap is formed between the cap nut and the board member or the movable base member, and the board member is urged toward the movable base member by the elasticity of the coil spring. . The substrate member and the movable base member are connected by a pair of inclination adjustment screws, and the pair of inclination adjustment screws connecting the substrate member and the movable base member are screwed in or unscrewed to unscrew the movable base member. The inclination of the substrate member with respect to the member is adjusted, and therefore the inclination angle of the objective lens is adjusted. Thereafter, after completion of such adjustment,
The cap nut is screwed in in a direction that compresses the coil spring, eliminating the gap between the cap nut and the board member or the movable base member, and fixing the board member to the movable base member.

By doing so, attachment of the substrate member to the movable base member and adjustment of the inclination angle of the objective lens are easily and efficiently performed. Furthermore, after the adjustment work, it is possible to avoid changes in the tilt angle of the objective lens due to external shocks, etc., and to readjust the tilt angle of the objective lens.

G Embodiment G-1 Overall Configuration (FIGS. 2 and 3) FIG. 3 shows a simplified overall structure of an example of an optical head device for a disk player according to the present invention.

In the example shown in FIG. 3, a laser beam emitted from a semiconductor laser 1 is diffracted by a grating 2 into three laser beams (in FIG. 3, for simplicity, these beams are (three laser light beams are shown as one line),
The beam is reflected by the plate beam splitter 3 and enters the collimator lens 4. And collimator lens 4
A laser beam that is collimated is made incident on the disk D through the objective lens 6, is modulated in the recording track formed on the disk D, and is reflected. A focus control drive section 11 and a tracking control drive section 12 are arranged around the objective lens 6.

The reflected laser light beam from the disk D sequentially passes through the objective lens 6 and the collimator lens 4 and returns, and after passing through the plate beam splitter 3, the beam returns to the correction glass plate 7 when passing through the plate beam splitter 3. The coma aberration caused by the light is corrected, and the light is guided to a photodetector 10 via a light receiving lens (concave lens) 8. The detection output obtained from the photodetector 10 is then supplied to a signal processing section (not shown) to form a reproduction information signal, a focus control signal, and a tracking control signal. The focus control signal and the tracking control signal are supplied to a focus control drive unit 11 and a tracking control drive unit 12, respectively, which are arranged in relation to the objective lens 6, thereby aligning the objective lens 6 with its optical axis. It is moved toward or away from the disk D in the direction along the line. A driving operation for focus control is performed, and the objective lens 6 is moved toward the disk D in a direction perpendicular to its optical axis.
A driving operation for tracking control is performed to move the area in the radial direction.

In this example, the semiconductor laser 1,
The grating 2, plate beam splitter 3, collimator lens 4, correction glass plate 7, light receiving lens 8, and photodetector 10 are mechanically combined into one block to form the light beam generation/detection unit 1.
4, and an objective lens 6,
The focus control drive section 11 and the tracking control drive section 12 are mechanically combined into one other block to constitute a two-axis drive unit 20. These light beam generation/detection unit 14 and biaxial drive unit 20 are, for example, as shown in FIG. 2, the light beam generation/detection unit 14 is a block housed in a rectangular exterior case 14a, Further, the two-axis drive unit 20 is a block housed in an exterior case 20a having an opening 20b at a position corresponding to the objective lens 6, and each has a guide shaft 16 extending along the radial direction of the disk D. It is attached to a movable base member 18 that moves while being guided by.

G-2 Installation of the two-axis drive unit (Fig. 1,
(FIG. 4) Thus, an example of the optical head device for a disk player according to the present invention has the light beam generation/detection unit 14 and is further equipped with the two-axis drive unit 20. The shaft drive unit 20 is attached to the movable base member 18 as shown in FIG. Note that the two-axis drive unit 20 itself has the same configuration as that shown in FIGS. 6 and 7 described above, so the structure shown in FIGS. 6 and 7 in FIG. Portions or members corresponding to each part or member are shown with the same reference numerals as in FIGS. 6 and 7, and redundant explanation of the biaxial drive unit 20 itself will be omitted. Furthermore, the two-axis drive unit 20 in FIG.
It is assumed that a is removed.

In FIG. 1, the movable base member 18 is provided with a spherical bearing portion 46 corresponding to the spherical shaft portion 45 provided on the base member 22, similar to that shown in FIGS. 6 and 7 described above. At the same time, through holes 40, 41 and 3 are provided at positions corresponding to the female threads 25, 26 and 27 formed in the substrate member 22.
9 are formed respectively. The female screw portions 25 and 26 formed on the substrate member 22 are provided with through holes 40 from the lower surface side of the movable base member 18.
and 41, the inclination adjusting screws 35 and 36 are screwed into the female threaded portion 27, and a connecting rod 80 is inserted into the female screw portion 27 from the lower surface side of the movable base member 18 through a through hole 39, and a male connecting rod 80 is formed at one end thereof. They are screwed together and fixed using the threaded portion 81.

As shown in detail in FIG. 4, this connecting rod 80 has a male threaded portion 81 formed at one end and a male threaded portion 82 formed at the other end. A washer 31 and a coil spring 32 are fitted into the connecting rod 80, and the coil spring 32 is connected to the washer 31 which is in contact with the lower surface of the movable base member 18. The cap nut 83 is screwed onto the male threaded portion 82 by compressing it. The connecting rod 80, washer 31, coil spring 32, and cap nut 83 constitute a connecting member, and this connecting member urges the base plate member 22 toward the movable base member 18. ing.

In the case of the biaxial drive unit 20 that includes such a connecting member, when the base plate member 22 is arranged and attached on the movable base member 18, for example, first, the female screw portion 27 of the base plate member 22 is
Then, the connecting rod 80 is screwed together with its male screw portion 81, and the connecting rod 80 is attached to the base plate member 22.
It is fixed so that it protrudes downward.
The entire biaxial drive unit 20 is then placed on the movable base member 18, with the connecting rod 80
is inserted into the lower surface side of the movable base member 18 through the through hole 39 provided on the movable base member 18, and the spherical shaft portion 45 provided on the base plate member 22 is inserted into the spherical bearing portion 46 provided on the movable base member 18. are adapted to engage.

Subsequently, the washer 31 and the coil spring 32 are attached to the connecting rod 80 from below, the cap nut 83 is screwed into the male threaded portion 82, and the female threaded portions 25 and 2 of the base plate member 22 are screwed.
6, the inclination adjustment screws 35 and 36 are inserted into through holes 40 and 41 formed in the movable base member 18, respectively.
The cap nut 83 is then screwed in from below through the cap nut 83 in a direction that compresses the coil spring 32. In that case, the screwing degree of the cap nut 83 is adjusted so that a slight gap is formed between the cap nut 83 and the lower surface of the movable base member 18, as shown in FIG.

In this state, the inclination adjustment screws 35 and 36 are screwed in or unscrewed, thereby connecting the substrate member 22 and the movable base member 18, and making the spherical shaft portion 45 of the substrate member 22 movable. The entire base member 22 is guided by the spherical bearing portion 46 of the base member 18 and is displaced.
It can be rotated slightly at the top. As a result, the tilt adjustment of the substrate member 22 with respect to the movable base member 18,
Therefore, the tilt angle of the objective lens 6 is adjusted.

After such adjustment is completed, the objective lens 6
With the inclination angle of the nut 8 set properly,
3 is further screwed in a direction that compresses the coil spring 32, so that the end surface of the cap nut 83 comes into contact with the lower surface of the movable base member 18. Thereby, while the tilt angle of the objective lens 6 with respect to the movable base member 18 is maintained appropriately, the substrate member 2
2 is fixed on the movable base member 18, and the attachment of the two-axis drive unit 20 to the movable base member 18 is completed.

In this way, the attachment of the substrate member 22 to the movable base member 18 and the adjustment of the inclination angle of the objective lens 6 are easily and efficiently performed, and after the adjustment, the cap nut 83 is attached so that its end face is connected to the movable base member. 1
Since the objective lens 6 is screwed in so as to come into contact with the lower surface of the objective lens 8, the inclination angle of the objective lens 6 is prevented from changing due to an external impact or the like. Furthermore, by loosening the cap nut 83, the tilt angle of the objective lens 6 can be readjusted.

H. Effects of the invention As is clear from the above explanation, according to the optical head device for a disk player according to the invention, the lens support member holds the objective lens and is movable in the direction along the optical axis and the direction perpendicular thereto. The two-axis drive unit, which consists of a magnetic yoke member arranged in relation to the lens support member and a substrate member therefor, is attached to the movable base member and the tilt angle of the objective lens is adjusted using the cap nut of the connecting member. The adjustment can be done extremely easily and efficiently by screwing in a pair of inclination adjustment screws with the screws loosened. Moreover, after the adjustment is completed, simply tighten the cap nut of the connecting member. , it is possible to avoid a situation where the tilt angle of the adjusted objective lens changes undesirably. Furthermore, by loosening the tightened cap nut again, the tilt angle of the objective lens can be readjusted.

[Brief explanation of the drawing]

FIG. 1 is a side view including a partial cross section showing essential parts of an example of an optical head device for a disk player according to the present invention, and FIG. 2 is an external perspective view of an example of the optical head device for a disk player according to the present invention. Third
FIG.
The figure is an exploded perspective view of a connecting member used in the main parts shown in Figure 1, Figure 5 is a simplified configuration diagram showing the entire conventional optical head device, and Figures 6 and 7 are conventional optical head devices. FIG. 3 is a plan view and a partially sectional side view for explaining the installation of the two-axis drive unit in the head device. In the figure, 6 is an objective lens, 14 is a light beam generator,
Detection unit, 18 is a movable base member, 20 is a biaxial drive unit, 22 is a substrate member, 32 is a coil spring, 35 and 36 are tilt adjustment screws, 38
8 is a hinge member, 48 is a bobbin member, 80 is a connecting rod, 81 and 82 are male threads, and 83 is a cap nut.

Claims (1)

[Claims for Utility Model Registration] An objective lens is held and a focus control coil and a tracking control coil are attached, and the objective lens is moved in a first direction along its optical axis and in a second direction orthogonal to the first direction. a lens support member that can be swung to be displaced in a direction; a substrate member having an upper surface portion to which the lens support member is attached; and a lower surface portion provided with a spherical shaft portion; and the spherical shaft portion engage with each other. a movable base member provided with a spherical bearing portion for adjusting the angle of inclination of the objective lens; It has a fixing part that is located on or near the orthogonal bisector of the line segment connecting the adjustment screws and is fixed to the substrate member or the movable base member, and a screw part is located on the end side remote from the fixing part. A connecting member comprising a formed connecting rod, a cap nut that is screwed into the threaded portion, and a coil spring that is disposed between the connecting rod and the cap nut and urges the substrate member toward the movable base member. The inclination angle of the objective lens is adjusted by screwing and adjusting the inclination adjustment screw by loosening the cap nut with respect to the screw portion and extending the coil spring. The disc player is in a state in which the adjusted tilt angle of the objective lens is maintained by tightening the cap nut against the screw portion and compressing the coil spring. optical head device.