JPH11203719A - Optical element holder, optical pickup, and optical disk device - Google Patents

Abstract

(57) [Problem] To provide an optical element holder in which the positioning of an optical element can be easily adjusted and its position does not move due to environmental change or the like, and an optical pickup and an optical disk apparatus using the same. SOLUTION: The mounting base 20a which supports the optical element 22 and has a peripheral surface 34a formed in a cylindrical shape around an axis parallel to the optical axis, and extends parallel to the optical axis.
The optical element holder 34 is housed in the V-groove 20b formed in the mounting base, and has a screw hole 34c on the peripheral surface thereof. The fixing screw 35 is screwed from the back surface of the mounting base and is fixed to the mounting base by being tightened.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mini disc (M
D), an optical pickup for recording and / or reproducing signals from a magneto-optical disk (MO), a compact disk (CD), a CD-ROM, etc. (hereinafter, referred to as an "optical disk"), and an optical disk provided with the optical pickup It concerns the device.

[0002]

2. Description of the Related Art Conventionally, an optical pickup for an optical disk is constructed, for example, as shown in FIG. In FIG. 8, an optical pickup 1 is reflected by a collimator lens 3, a grating 4, a beam splitter 5, and a beam splitter 5, which are sequentially arranged in the optical path of a light beam emitted from a semiconductor laser element 2 as a light source. An objective lens 6 disposed in the optical path, and a beam splitter 5
And a return collimator lens 7, a multi-lens 8, and a photodetector 9 which are sequentially arranged in a separation optical path of return light from the optical disk D that has passed through the optical disk D. Here, the objective lens 6 is supported by a biaxial actuator so as to be movable in a biaxial direction, that is, a focus direction and a tracking direction. On the other hand, other optical elements, that is, the semiconductor laser element 2, the collimator lens 3, the grating 4, the beam splitter 5, the return collimator lens 7, the multi-lens 8, and the photodetector 9 are fixedly arranged on an optical base (not shown). Have been.

In the optical pickup 1 having such a configuration, the light beam from the semiconductor laser element 2 is converted into parallel light by a collimator lens 3 and then divided by a grating 4 into three parts. The light is reflected by 5a and is irradiated on the signal recording surface of the optical disk D by the objective lens 6. At this time, each light beam divided into three by the
Two spots are formed. The return light beam reflected by the signal recording surface again enters the beam splitter 5 via the objective lens 6, passes through the separation surface, is focused by the return collimator lens 7, and is focused by the multi-lens 8. The astigmatism is given and the optical path length is adjusted, the light is received by the light receiving surface of the photodetector 9, and the recording signal is detected. Here, the grating 3
A tracking error signal is detected based on each light beam split by b.

[0004] In order to accurately detect a reproduced signal,
The objective lens 6 is finely moved based on a predetermined servo signal so that a light beam from the semiconductor laser element 2 forms a spot at a correct position on the signal recording surface of the optical disc and an accurate recording signal is reproduced. It is supposed to be. The servo of the objective lens 6 includes a tracking servo for finely moving the objective lens 6 along the radial direction of the optical disk with respect to a recording track of the optical disk, and a direction for moving toward and away from the signal recording surface of the optical disk along the optical axis. A focusing servo for finely moving the objective lens 6 is performed.

[0005]

By the way, in the optical pickup 1 having such a configuration, for example, the collimator lenses 3 and 7 are supported by a cylindrical lens holder, and this lens holder is housed in an optical base. Have been. Then, with this lens holder pressed against the bottom of the optical base by, for example, a metal spring,
Further, the lens holder is fixed to the optical base by an adhesive.

However, in such a method of fixing the lens holder, the lens holder moves within the optical base due to expansion and contraction due to a change in the environment of the adhesive, and a lens position shift occurs. For this reason, since the light beam from the semiconductor laser element 2 is not changed into the parallel light by the collimator lens 3, there is a problem that the reliability of the optical pickup and the optical disk device is reduced. In particular, in an optical pickup corresponding to a high-density recording type optical disk, there has been a problem that if the collimator lens is not accurately positioned, parallel light corresponding to required performance cannot be obtained.

SUMMARY OF THE INVENTION In view of the above, the present invention provides an optical element holder in which the positioning of an optical element can be easily adjusted and its position does not move due to environmental changes or the like, and an optical pickup and an optical disk apparatus using the same. It is intended to be.

[0008]

According to the present invention, there is provided an optical element for supporting an optical element, the peripheral surface of which is formed in a cylindrical shape around an axis parallel to the optical axis. An optical element holder housed in a V-groove formed in the mounting base so as to extend in parallel with the optical element holder, provided with a screw hole on a peripheral surface thereof, in a state housed in the V-groove of the mounting base. This is achieved by an optical element holder that is fixed to the mounting base by screwing a fixing screw into the screw hole from the back surface of the mounting base and tightening.

According to the above configuration, the optical element holder for supporting the optical element is brought into contact with the inner surface of the V-groove formed in the mounting base so that the optical axis of the optical element in the holder is aligned. , Easily matched with the optical axis of the optical system. Furthermore, in this state, it is fixed to the mounting base by being tightened from the back surface of the mounting base with a fixing screw. Accordingly, the optical element holder is securely fixed and held to the mounting base, and the optical element holder does not move in the V-groove with respect to the mounting base due to an environmental change or the like. .

When the fixing screw is tightened after the optical element holder is moved and adjusted along the V-groove in a state where the optical element holder is in contact with the inner surface of the V-groove, the optical element is not moved. The optically adjusted position is securely fixed and held.

In the case where an adjusting groove formed in a direction perpendicular to the optical axis is provided on a peripheral surface opposite to the screw hole,
Before the fixing screw is tightened, the adjustment pin of the adjustment tool is inserted into the adjustment groove, and the optical element holder can be easily moved and adjusted in the optical axis direction within the V groove.

In the case where the notch is formed so as to have a plane parallel to the optical axis in the region of the adjusting groove on the peripheral surface, the optical element holder is moved by the adjusting tool in the optical axis direction. At the time of adjustment, the adjustment pin of the adjustment tool does not slip on the cylindrical peripheral surface of the optical element holder, and is easily inserted into the adjustment groove in the plane of the notch.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to FIGS. still,
Since the embodiments described below are preferred specific examples of the present invention, various technically preferred limitations are added.
The scope of the present invention is not limited to these embodiments unless otherwise specified in the following description.

FIG. 1 shows an overall configuration of an optical disk apparatus incorporating an embodiment of an optical element holder according to the present invention. In FIG. 1, an optical disk device 10 includes a spindle motor 12 as a driving means for rotatingly driving an optical disk 11, and a signal recording surface of the rotating optical disk 11 which is irradiated with a light beam to record a signal. An optical pickup 20 for reproducing a recording signal by a return light beam from the optical pickup 20 and a control unit 13 for controlling the optical pickup 20 are provided. Here, the control unit 13 includes an optical disk controller 14, a signal demodulator 15, an error correction circuit 16, an interface 17, a head access control unit 18, and a servo circuit 19.

The optical disk controller 14 controls the drive of the spindle motor 12 at a predetermined rotation speed. The signal demodulator 15 demodulates the recording signal from the optical pickup 20, corrects the error, and sends the signal to an external computer or the like via the interface 17. Thus, an external computer or the like can receive a signal recorded on the optical disk 11 as a reproduction signal.

The head access control unit 18 moves the optical pickup 20 to a predetermined recording track on the optical disk 11, for example, by a track jump or the like. The servo circuit 19 moves the objective lens held by the biaxial actuator of the optical pickup 20 in the focusing direction and the tracking direction at the moved predetermined position.

FIG. 2 shows the structure of the optical pickup 20 incorporated in the optical disk device 10. FIG.
In the optical pickup 20, a collimator lens 22, a half-wave plate 23, a grating 24 as a light splitting means, which are sequentially arranged in the optical path of a light beam emitted from a semiconductor laser element 21 as a light source, Anamo prism 25, beam splitter 2 as light separating means
A return collimator lens 30, a multi-lens 31, and a photodetector, which are sequentially disposed in a separation optical path by a beam splitter 26, and a 6/4 wavelength plate 27, a rising mirror 28, and an objective lens 29 as a light focusing unit Device 32.

Here, each optical element except the objective lens 29, ie, the semiconductor laser element 21, the collimator lens 2
2, 1/2 wavelength plate 23, grating 24, anamorphic prism 25, beam splitter 26, 1/4 wavelength plate 2
7, the rising mirror 28, the return collimator lens 30, the multi-lens 31, and the photodetector 32 are supported movably in the radial direction of the optical disk 11 along a guide (not shown) provided on the optical pickup 20. The optical bases 20a are fixedly held.

The semiconductor laser element 21 is a light emitting element utilizing recombination light emission of a semiconductor, and emits a predetermined laser beam.

The collimator lens 22 is a convex lens, and converts light from the semiconductor laser device 21 into parallel light. The half-wave plate 23 is provided with the semiconductor laser element 21.
Is converted into a specific polarization to correct astigmatism of the light beam.

The grating 24 is a diffraction grating for diffracting incident light, and converts the light beam from the half-wave plate 23 into at least a main beam composed of zero-order diffracted light and a side beam composed of plus or minus first-order diffracted light. It is split into three light beams. Therefore, another division element such as a hologram element may be used as long as at least three light beams can be divided and generated.

The anamorphic prism 25 splits the light beam from the grating 24 and reflects a part of the light beam to guide the light beam to the monitoring photodetector 33, and transmits a part of the light beam to the beam splitter 26. I have.

The beam splitter 26 has a separation film 26
a is arranged at an angle of 45 degrees with respect to the optical axis, and separates the light beam from the semiconductor laser element 21 and the return light from the signal recording surface of the optical disk 11. That is, the light beam from the semiconductor laser element 21 is reflected by the separation film 26a of the beam splitter 26, and the return light beam is transmitted through the separation film 26a of the beam splitter 26. In the case shown in the figure, the beam splitter 26 is configured so that the return light transmitted through the separation film 26a is reflected on the reflection surface thereafter, whereby the optical path is bent.

The start-up mirror 28 is mounted on the optical disk 11
The light beam from the beam splitter 26 is reflected 90 degrees in the vertical direction, and the return light beam from the optical disk 11 is reflected 90 degrees in the horizontal direction. .

The objective lens 29 is a convex lens and focuses the light beam from the beam splitter 26 on a desired recording track on the signal recording surface of the optical disk 11 that is driven to rotate. Here, the objective lens 29 is supported by a biaxial actuator (not shown) so as to be movable in biaxial directions, that is, in a focus direction and a tracking direction.

The return collimator lens 30 is a convex lens and focuses a return light beam, which is parallel light from the optical disk 11. Multi lens 31
Denotes a cylindrical lens and a concave lens, which imparts astigmatism to incident light and adjusts an optical path length for detecting a focus error signal on a return light beam.

The photodetector 32 is configured to have a light receiving portion for the return light beam transmitted through the beam splitter 26.

Here, the collimator lens 22 is attached to the optical base 20a as shown in FIGS. 3 and 4, the collimator lens 22 is supported by a hollow cylindrical lens holder. As shown in FIGS. 5 to 7, this lens holder 34 has a cylindrical surface 34a and a stepped portion as an abutting surface with which the peripheral edge of the collimator lens 22 comes into contact with the hollow portion. 34b. In addition, the lens holder 34 has a threaded hole 34c near the upper end in FIGS.
On the side opposite to the screw hole 34c, there is provided an adjusting groove 34d extending perpendicularly to the optical axis (that is, in the direction perpendicular to the paper surface in FIG. 5, and in the horizontal direction in FIG. 6).
A notch 24e defining a flat surface in the region d is provided.

On the other hand, as shown in FIGS. 3 and 4, the optical base 20a is provided with a V-groove 20b formed so as to extend along the optical axis direction. This V-groove 2
Ob is formed such that its inner surface is inclined at about 45 degrees with respect to a plane perpendicular to the optical axis, and is substantially perpendicular to each other. Further, the V groove 20b has a through hole 20c penetrating to the back side at the bottom. As shown in FIG. 3, the through-hole 20c is a long hole that is elongated in a direction parallel to the optical axis.

The optical disk device 10 incorporating the optical pickup 20 according to the present embodiment is configured as described above, and operates as follows. First, the optical disk 11 is rotationally driven by the rotation of the spindle motor 12 of the optical disk device 10. Then, the optical pickup 20 moves the optical disc 1 along a guide (not shown).
1 in the radial direction, the objective lens 29
Is moved to the desired track position of the optical disk 11 to perform access.

In this state, in the optical pickup 20, the light beam from the semiconductor laser element 21 is converted into a parallel light by the collimator lens 22, and the half-wave plate 2
3 corrects the astigmatism, and the grating 2
After being split into three light beams by 4, the light beam is incident on a beam splitter 26 through an anamorphic prism 25, is reflected by the separation film 26 a, and passes through a 波長 wavelength plate 27.
The light is reflected toward the optical disk 11 by the rising mirror 28, and is focused on the signal recording surface of the optical disk 11 via the objective lens 29. The return light from the optical disk 11 again enters the beam splitter 26 via the objective lens 29 and the rising mirror 28. Then, after passing through the separation film 26 a of the beam splitter 26, the optical path is bent by reflection, focused by the return collimator lens 30, and further passed through the multi-lens 31 to the photodetector 32.
Image. Thereby, the recording signal of the optical disk 11 is reproduced based on the detection signal of the photodetector 32.

At this time, the signal demodulator 15 is provided with a photodetector 32
, A tracking error signal is detected by the detection signal, and a focusing error signal is detected by the astigmatism method. Then, the servo circuit 19 performs servo control via the optical disk drive controller 14 to perform focusing and tracking.

In such an optical pickup 20, the collimator lens 22 is attached to the lens holder 34 with an adhesive or the like in a state where the periphery of the collimator lens 22 is abutted against the step 34b in the lens holder 34. As a result, the lens holder 34 is housed in the V groove 20b of the optical base 20a, and its cylindrical peripheral surface is
The fixing screw 35 is screwed into the screw hole 34c from below the optical base 20b through the through hole 20c while being in contact with the inner surface of the optical base 20b. From this state, an eccentric adjustment pin (not shown) of the adjustment tool is inserted into the adjustment groove 34d of the lens holder 34 from above. At this time, since the region of the adjustment groove 34d is formed flat by the notch 34e, the adjustment pin of the adjustment tool is smoothly inserted into the adjustment groove 34d.

When the adjustment tool, for example, an eccentric driver is rotated, the adjustment pin moves in the optical axis direction, and the lens holder 34 is moved based on the engagement of the adjustment pin into the adjustment groove 34d. The movement is adjusted in the optical axis direction. After the movement adjustment of the lens holder 34 is completed, the fixing screw 35 is tightened, so that the lens holder 34 is fixed to the optical base 20a with its peripheral surface abutting on the inner surface of the V groove 20b.
In this case, when the lens holder 34 is tightened with respect to the V-groove 20b, the peripheral surface of the lens holder 34 is drawn into the V-groove 20b, and the inner surface of the V-groove 20b in the direction perpendicular to the optical axis. In addition to being regulated, the frictional force between the peripheral surface and the inner surface of the V-groove 20b also regulates the optical axis direction. Therefore, since the tightening force of the fixing screw 35 is always applied to the lens holder 34, the lens holder 34
It does not move in the groove 20b, and the optical position of the collimator lens 22 does not shift.
Accordingly, the collimator lens 22 can form highly accurate parallel light in the above-described optical system in correspondence with a high-density recording type optical disk. Thus, the reliability of the optical pickup 20 incorporating the collimator lens 22 and the optical disk device 10 is improved.

As described above, according to the above-described embodiment, the optical element holder supporting the optical element is brought into contact with the inner surface of the V-groove formed in the mounting base and the back surface of the mounting base. From the mounting base. This allows
The optical element holder is securely fixed to the mounting base, so that the optical element holder does not move in the V-groove with respect to the mounting base due to an environmental change or the like. Therefore, there is no occurrence of optical displacement of the optical element, and the reliability of the optical equipment such as an optical pickup and an optical disk device in which the optical element is incorporated is improved.

In the above embodiment, only the collimator lens 22 is connected to the V-groove 20 b via the lens holder 34.
However, the present invention is not limited to this. For example, the return collimator lens 30 is also screwed into a V-groove provided in the optical base 20b using a cylindrical lens holder. As long as the optical position is adjusted in the optical axis direction, the other optical elements may be screwed into the V-groove provided on the optical base by the cylindrical lens holder in the same manner. It is clear that this may be done.

In the above embodiment, the case where the collimator lens 22 of the optical disk device 10 and the optical pickup 20 is attached to the optical base 20b so as to be movable and adjustable in the optical axis direction is described.
The present invention is not limited to this, and it is apparent that the present invention can be applied to any other optical device that can be moved and adjusted in the optical axis direction.

[0038]

As described above, according to the present invention, the positioning of the optical element can be easily adjusted and the position of the optical element can be prevented from moving due to environmental changes, and the optical pickup and optical disk using the same. An apparatus can be provided.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the overall configuration of an optical disk device incorporating an embodiment of an optical element holder according to the present invention.

FIG. 2 is a plan view showing a configuration of an optical pickup in the optical disk device of FIG.

FIG. 3 is an enlarged sectional view taken along an optical axis near a collimator lens in the optical pickup of FIG. 2;

FIG. 4 is an enlarged cross-sectional view of the vicinity of the collimator lens of FIG. 3 perpendicular to the optical axis.

FIG. 5 is a sectional view taken along an optical axis showing a lens holder of the collimator lens in FIG. 3;

FIG. 6 is a cross-sectional view of the lens holder of FIG. 5 perpendicular to the optical axis.

FIG. 7 is a perspective view of the lens holder of FIG.

FIG. 8 is a plan view showing a configuration of an example of a conventional optical pickup.

[Brief description of reference numerals]

10 optical disk device, 11 optical disk, 1
2 ... Spindle motor, 13 ... Control unit, 14.
..Optical disk drive controller, 15 ... signal demodulator, 16 ... error correction circuit, 17 ... interface, 18 ... head access control unit, 20 ...
-Optical pickup, 21 ... semiconductor laser element, 2
2 ... collimator lens, 23 ... 1/2 wavelength plate,
Reference numeral 24: grating, 25: anamorphic prism, 26: beam splitter, 27: quarter-wave plate, 28: rising mirror, 29: objective lens, 30: return Collimator lens, 31 multi-lens, 32 photodetector, 33 photodetector for monitoring, 34 lens holder, 34a cylindrical peripheral surface, 34b step Part, 34c ... screw hole, 3
4d adjustment groove, 34e notch, 35 fixing screw.

Claims (7)

[Claims] 1. A V-groove for supporting an optical element, having a peripheral surface formed in a cylindrical shape around an axis parallel to an optical axis, and formed in a mounting base so as to extend parallel to the optical axis. The optical element holder is housed in the optical element holder, and has a screw hole on a peripheral surface thereof. In the state of being housed in the V groove of the mounting base, a fixing screw is inserted into the screw hole from the back surface of the mounting base. An optical element holder, which is fixed to a mounting base by being screwed and tightened. 2. The optical element holder according to claim 1, wherein
2. The optical element holder according to claim 1, wherein the fixing screw is tightened after being moved and adjusted along the V-groove in a state of being in contact with the inner surface of the groove. 3. The optical element holder according to claim 1, wherein an adjustment groove formed in a direction perpendicular to the optical axis is provided on a peripheral surface opposite to the screw hole. 4. The optical element holder according to claim 3, wherein a notch is formed so as to have a plane parallel to the optical axis in a region of the adjustment groove on the peripheral surface. 5. The optical element holder according to claim 1, wherein the optical element held in the optical element holder is a collimator lens. 6. A light source that emits a light beam, a collimator lens that converts the light beam emitted from the light source into parallel light, and a signal recording surface of an optical disc that is driven to rotate the parallel light from the collimator lens. A light focusing means for focusing, a light separating means disposed between the light source and the light focusing means, and a light receiving unit for receiving a return light beam from a signal recording surface of the optical disc separated by the light separating means. A light detector, an optical base for fixedly holding the light source, the collimator lens, the light separating means and the light detector, and a cylindrical surface around the axis which supports the collimator lens and whose peripheral surface is parallel to the optical axis. And an optical element holder accommodated in a V-groove formed in the optical base so as to extend in parallel with the optical axis. A fixing screw is screwed into the screw hole from the back surface of the optical base in a state housed in the V-groove of the optical base, and is fixed to the optical base by being tightened. An optical pickup characterized in that: 7. A driving means for driving the optical disc to rotate, and a light source irradiating the rotating optical disc with light from a light source via a light focusing means, and returning light from a signal recording surface from the optical disc through the light focusing means. An optical pickup that detects with a photodetector, a biaxial actuator that supports the objective lens movably in biaxial directions, a signal processing circuit that generates a reproduction signal based on a detection signal from the photodetector, A servo circuit that moves the light focusing means in two axial directions based on the detection signal from the optical pickup, and holds a collimator lens among the optical elements constituting the optical pickup, and has a peripheral surface thereof. An optical element holder which is formed in a cylindrical shape around an axis parallel to the optical axis and is housed in a V-groove formed in the optical base so as to extend parallel to the optical axis. The optical element holder is provided with a screw hole on its peripheral surface, and a fixing screw is screwed into the screw hole from the rear surface of the optical base in a state of being housed in the V-groove of the optical base. An optical disc device, characterized in that the optical disc device is fixed to an optical base.