JPS6349864Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is a skew detection device for an optical disc device that is applied to recording and reproducing optical discs such as video discs and audio discs. It consists of a lens, and a diffused light source and a two-split photodetector arranged on the same focal plane of the lens and distributed in a direction perpendicular to the optical axis of the lens, and the diffused light from the diffused light source is The recording surface of the optical disk is irradiated by a lens, and the reflected light is received by the lens across two light-receiving areas of the two-split photodetector, and a light-receiving image in the two light-receiving areas is created. The present invention relates to a skew detection device for an optical disk device configured to detect the direction and amount of skew of the optical disk based on the difference in detection outputs.

[Background technology and its problems] In the reading optical system of an optical disk device, a laser beam emitted from a laser light source is converged by an objective lens into a beam spot, and this beam spot is irradiated onto the recording surface of the disk. Then, the information on the recording surface of the disk is read by the reflected light. At this time, focus control is performed so that the beam spot is focused on the recording surface of the disk, and tracking control is performed so that the optical axis coincides with the information pit row forming the track on the recording surface of the disk. However,
Since the beam spot has a finite spread determined by the wavelength of the laser light source and the numerical aperture of the objective lens, it is possible that the optical axis of the laser beam is not perpendicular to the recording surface of the disk (hereinafter referred to as disk skew). , comatic aberration occurs at the spot on the recording surface, and this spot is deteriorated. In this case, since the track pitch on the recording surface of the disk is very small, crosstalk in which the beam spot reads information from adjacent tracks becomes a major problem.

By the way, there are various causes of disk skew, where the optical axis of the laser beam and the recording surface of the disk are not perpendicular, such as tilting of the spindle axis, bending of the disk holder, and warping of the disk itself, but the main cause is the disk itself. The skew is particularly large in the radial direction. For this reason,
It is necessary to detect skew in the radial direction of the disk (including causes other than warpage of the disk itself) and take measures against increased crosstalk.

Various methods have been proposed for this skew detection. For example, there are methods of detecting reflected light from the disk within a reading optical system, methods of detecting reflected light by providing a laser light source separate from the reading optical system, and the like. However, all of these methods have the problem of being complicated and expensive.

As a solution to this problem, the present inventor previously proposed a skew detection device that has an extremely simple structure and is inexpensive. First, this skew detection device, which is the premise of the present invention, will be explained.

Figures 1 to 3 show this skew detection device 1. Figure 1 is a view from the top side of the disk 2 (however, the disk is not shown), and Figure 2 is a view from the radial direction of the disk 2. 3 and 3 are views of the disk 2 viewed from the track direction (each shown in cross-sectional view for explanation).

This skew detection device 1 uses a diffused light source as a light source, and in the examples shown in FIGS. 1 to 3, a light emitting diode 3 whose light emitting surface diffuses light is used. Further, a two-split photodetector 5 is provided which receives the diffused light from the light emitting diode 3 reflected by the disk 2 through a lens 4. This two-split photodetector 5 has two light receiving areas 5a and 5b. The light emitting diode 3, lens 4, and two-part photodetector 5 are attached to a housing member 6 having a substantially cylindrical shape. That is, the lens 4 is disposed on one open end side of the housing member 6, and the light emitting diode 3 and the two-split photodetector 5 are disposed on the other open end side at the focal plane position of the lens 4. are arranged in a direction perpendicular to the optical axis OA. Then, as shown in the figure, the housing member 6 in which the light emitting diode 3, the lens 4 and the two-split photodetector 5 are disposed is arranged so that the lens 4 is on the disk 2 side and the light emitting diode 3 and the two-split photodetector 5 are arranged. 5 are arranged so as to be lined up in a direction perpendicular to the skew detection direction of the disk 2. In this example, since the skew in the radial direction of the disk 2 is detected, the light emitting diode 3 and the two-split photodetector 5 are arranged in a direction perpendicular to the radial direction of the disk 1 (track direction). . Further, in this case, the optical axis OA of the lens 4 is installed so as to be perpendicular to the recording surface of the disk 2 when the optical axis of the optical pickup, which is a reading optical system, is perpendicular. Further, the dividing line 5c of the two-split photodetector 5 is arranged in a direction perpendicular to the skew detection direction, that is, a direction perpendicular to the radial direction of the disk 2, and intersects with a plane including the optical axis OA of the lens 4. Ru.

Incidentally, FIG. 4 shows a perspective view of only the light emitting diode 3 and the two-split photodetector 5.

With this configuration, two of the two-split photodetector 5
An image of diffused light on the surface of the light emitting diode 3 is received by the two light receiving areas 5a and 5b as a light receiving image 7 shown with diagonal lines in FIG. The principle behind this is shown in FIG.

That is, if the optical axis OA of the lens 4 and the recording surface of the disk 2 are perpendicular, the optical paths of the incident light and the reflected light to the recording surface of the disk 2 will be completely symmetrical.
Therefore, including the optical axis OA of the lens 4, the disk 2
An image of the light emitting diode 3 on the right side of the plane along the radial direction is formed on the focal plane of the lens 4 on the left side of the plane. In this figure 5, disk 2
The part indicated by the imaginary line above is disk 2.
Since this is the portion reflected by the recording surface of the disk 2, when it is folded back by the recording surface of the disk 2, it becomes as shown by the solid line in FIG. 5, and the image of the surface portion of the light emitting diode 3 is
The received light image 7 is just formed at the position of the two-split photodetector 5 .

When the optical axis OA of the lens 4 and the recording surface of the disk 2 are perpendicular to each other as shown in FIG. The same amount of light is received across the two light receiving areas 5a and 5b. Therefore, the light detection outputs from each light receiving area 5a and 5b are equal, and the difference therebetween is zero.

When the optical axis OA of the lens 4 and the recording surface of the disk 2 are no longer perpendicular to each other due to the skew of the disk 2, as shown in FIG. Due to the tilted disk 2, the light is shifted in the radial direction, so that the received light image 7 of the two-split photodetector 5 is such that more light is received on the one light receiving area 5b side, as shown by the imaginary line in FIG. will be done. Also, if the disk 2 has a skew on the opposite side to the state shown in FIG. 7, that is, the right side in the figure is downward,
The light-receiving image 7 of the two-split photodetector 5 is the other light-receiving area 5.
The light is received so that it is contained more in the a side.

From the above, the direction and amount of skew of the disk 2 can be detected based on the difference in detection output of the light-receiving image 7 in the two light-receiving areas 5a and 5b of the two-split photodetector 5.

Skew detection device 1 for disk 2 as described above
is used to control the optical axis of the optical pickup to be perpendicular to the recording surface of the disk 2 in the following manner.

That is, first, the light emitting diode 3 and the two-split photodetector 5 are made to maintain the above-mentioned relationship with respect to the optical pickup and to be movable together with the optical pickup as will be described later.

FIG. 8 shows an example of the configuration of a movable part including this optical pickup and skew detection device. In the figure, reference numeral 10 indicates an optical block, in which an optical pickup 11 for reading information recorded by pits on the disk 2 and the skew detection device 1 for detecting skew on the disk 2 are installed. . In addition, optical pick-up 1
Focus control and tracking control for the first optical system are performed by the two-axis optical drive unit 12 in the same manner as in the conventional art. The housing member 6 of the skew detection device 1 is attached to the optical block 10 so that the optical axis OA of the lens 4 is located in the longitudinal direction of the recording track in the vicinity of the optical axis OB of the optical pickup 11. Therefore, the optical axis of lens 4
The surface including OA is configured to also include the optical axis OB of the optical pickup 11.

The optical block 10 constructed as described above is supported entirely by a shaft 13 extending perpendicularly to the radial direction of the disk 2, and is swung in the radial direction of the disk 2. That is, in this example, the optical block 10
A worm wheel 14 is attached to the bottom of the
The shaft hole 1 of the two side plates 18 is arranged so that the worm wheel 14 meshes with the worm 17 rotated by the motor 16 installed on the feed block 15.
The shaft 13 is inserted through the shaft 9 . In addition, feed block 1
5 is slidably guided in the radial direction of the disk 2 by a pair of guide shafts 20. When the worm 17 is rotated by the motor 16, the worm wheel 14 is rotated by a rotation angle corresponding to the rotation, thereby causing the optical block 10 to swing in the radial direction of the disk 2. Therefore, by controlling the motor 16 using the detection output of the skew detection device 1, it is possible to control the optical axis OB of the optical pickup 11 so that it is always perpendicular to the recording surface of the disk 2.

However, in an optical disk device having the skew detection device 1 configured as described above, it is necessary to adjust the neutral point for skew detection when the disk device is assembled. That is, this type of apparatus has various errors such as inclination of the spindle axis, accuracy or assembly error of each mechanical component, coma aberration in the optical system of the optical pickup 11, and other errors. Therefore, when the device is assembled, the optical axis OA of the skew detection device 1 will not be perpendicular to the disk due to these total errors even if a disk without skew is installed. Discrepancies occur. For this reason, 2 in the skew detection device 1
The light-receiving image 7 in the two light-receiving areas 5a and 5b of the split photodetector 5 is shifted to either the light-receiving area 5a or 5b from the beginning. Therefore, once the device is assembled, it is necessary to make adjustments to return it to the neutral point so that there is no deviation.

However, in the above-described skew detection device 1, this adjustment was performed by tilting the entire skew detection device 1 with respect to the optical block 10.
That is, when the disk device is assembled, disk 2 is played back and the data is recorded on disk 2.
Read RF signals. Then, the optical block 10 is tilted so that the reproduced RF signal has a maximum value. The state where the RF signal reaches its maximum value is the state where the RF signal reaches its maximum value.
Since the optical axis OB of the optical pickup 11 is perpendicular to the optical block 10, the skew detection device 1 is further tilted with respect to the optical block 10 in this state,
Adjustment is made to a neutral point so that the light-receiving image 7 on the two-split photodetector 5 equally spans the two light-receiving areas 5a and 5b. After adjusting the neutral point of the skew detection device 1 in this way, if the skew detection device 1 is fixed to the optical block 10, from then on, if the detection output from the skew detection device 1 is zero, the optical pickup 11 optical axis OB is disk 2
perpendicular to.

However, although the skew detection device 1 has a simple structure, the method of tilting the entire skew detection device 1 with respect to the optical block 10 as described above requires a complicated adjustment mechanism and a large number of parts. Therefore, there was a problem that the cost was extremely high. Furthermore, the method of tilting the entire skew detection device 1 has the problem that the adjustment work is troublesome and time-consuming, and the work efficiency is extremely low.

[Purpose of the invention] The present invention aims to provide a skew detection device for an optical disk device that can solve the above-mentioned problems.

[Summary of the invention] The present invention provides the skew detection device for the optical disk device described above, in which the diffused light source and the two-split photodetector are mounted on a fixed base, and and at least a movable stage movable in the divided direction of the two light receiving areas of the two-split photodetector is provided, the lens is attached to the movable base, and the movable base is adjusted to move relative to the fixed base. An adjustment mechanism is provided, and by moving and adjusting the lens using the adjustment mechanism, the received light image received across the two light receiving areas of the two-split photodetector is adjusted to a neutral point. It is something.

According to the present invention, by simply moving the moving table, only the lens can be moved and the received light image can be adjusted to the neutral point, making the adjustment work extremely easy and greatly improving work efficiency. can. Furthermore, the structure of the adjustment mechanism is extremely simple and the number of parts is reduced, resulting in a significantly lower cost.

[Example] Hereinafter, an example of the present invention will be described based on FIGS. 9 to 16. Note that the same reference numerals are given to the same structural parts as in the conventional example described above, and the explanation thereof will be omitted.

First, FIGS. 9 to 12 show a first embodiment. In this first embodiment, the housing member of the skew detection device 1 includes a movable base 23 and a fixed base 24, as shown in FIGS. 9 and 10.
It is made up of. This moving table 23 and fixed table 2
Reference numeral 4 has a substantially cylindrical shape, and the lens 4 is mounted on the upper end side of the movable table 23, and the light emitting diode 3, which is a diffused light source, and the two-split photodetector 5 are placed on the lower end side of the fixed table 24, respectively. installed. Note that the positional relationship between the lens 4, the light emitting diode 3, and the two-split photodetector 5 is the same as that described above.

Thus, an eccentric convex portion 25 whose outer circumferential surface is decentered with respect to the optical axis OA of the lens 4 is integrally formed at the lower part of the movable table 23 . On the other hand, the inner peripheral surface of the upper part of the fixed base 24 is located at the optical axis of the lens 4.
An eccentric recess 26 eccentric to the OA is integrally formed. Note that the eccentric convex portion 25 and the eccentric concave portion 26 are the adjustment mechanism in the present invention. The outer circumferential surface of the eccentric convex portion 25 and the inner circumferential surface of the eccentric concave portion 26 have the same diameter, and the center C thereof is located at the first
As shown in Figure 0 and Figure 11, the optical axis of the lens 4
It is eccentric by △ε with respect to OA. Therefore, the eccentric convex portion 25 of the movable table 23 is placed in the eccentric concave portion 26 of the fixed table 24.
By fitting the movable base 23 with the fixed base 2, the movable base 23 is moved horizontally in a direction perpendicular to the optical axis OA of the lens 4, that is, while keeping the lens 4 on the same plane.
It is configured to be rotatable with respect to 4. Then, when the moving table 23 is rotated, the lens 4 is moved along its optical axis.
The OA is rotated in a circle with a radius Δε centered on the eccentric center C. Note that the position indicated by the imaginary line in FIGS. 10 and 11 is the position of the moving table 23.
is rotated 180 degrees from the solid line state with respect to the fixed base 24, and the optical axis OA of the lens 4 is moved to OA'. Further, an adjustment hole 27 is provided on one side of the outer periphery of the movable base 23, and furthermore, an adjustment hole 27 is provided on one side of the outer periphery of the movable base 23.
A screw hole 28 penetrating into the eccentric recess 26 is provided on one side of the outer periphery of the screw 4, and a locking screw 29 is screwed into this screw hole 28.

According to the first embodiment of the present invention configured as described above, the skew detection of the disk 2 by the skew detection device 1 is performed in exactly the same manner as in the prior art. Therefore, the position of the light-receiving image 7 in the two light-receiving areas 5a and 5b of the two-split photodetector 5 can be moved and adjusted very easily. Therefore, this principle was introduced in the 12th
This will be explained using figures.

That is, when the optical axis OA of the lens 4 and the recording surface of the disk 2 are perpendicular to each other as described above, the received light image 7 is the result of the two received lights of the two-split photodetector 5, as shown by the solid line. The same amount of light is received across regions 5a and 5b. When the movable table 23 is slightly rotated in the direction of arrow a with respect to the fixed table 24, the optical axis OA of the lens 4 draws an arc of radius Δε centered on the center of eccentricity C, as shown by a dashed line. moved to position. Here, since the light-receiving image 7 on the two-split photodetector 5 can always be located at the opposite position (conjugate position) to the light-emitting diode 3 with respect to the optical axis OA of the lens 4, the light-receiving image 7 on the two-split photodetector 5 is Its center is moved in the direction in which the optical axis OA of the lens 4 moves, drawing an arc with a radius of 2·Δε. Therefore, more of the light-receiving image 7 is included in one light-receiving region 5a side of the two-split photodetector 5, as shown by the dashed line. Further, when the movable table 23 is slightly rotated in the direction of arrow b with respect to the fixed table 24, the lens 4 is moved to the position shown by the chain double-dashed line, and the received light image is moved by the movement of the lens 4. 7 is included more on the other light-receiving region 5b side of the two-split photodetector 5, as shown by the two-dot chain line.

In this manner, by rotating the movable table 23 with respect to the fixed table 24, the position of the received light image 7 on the two-split photodetector 5 can be freely moved. Therefore, when the device is assembled, if the position of the light-receiving image 7 on the two-split photodetector 5 is shifted toward the light-receiving area 5a, for example, the moving table 23 should be rotated in the direction of the arrow b. Accordingly, the displacement of the light-receiving image 7 can be returned to the neutral point.

In addition, in order to rotate the moving table 23 with respect to the fixed table 24, as shown in FIG. 10, an adjustment rod 30 is inserted into the adjustment hole 27 provided in the moving table 23,
This adjustment rod 30 may be moved horizontally as shown in FIG. and 2 of the 2-split photodetector 5
After adjusting the light-receiving images 7 in the two light-receiving areas 5a and 5b to the neutral point, as shown in FIG.
is fixed to the fixing base 24. Note that this fixing is done by pouring adhesive etc. into the screw holes 28 and fixing the movable base 2.
3 and the fixing base 24 may be fixed together.

As described above, in the first embodiment of the present invention, the lens 4 is attached to the moving table 23, the light emitting diode 3 and the two-split photodetector 5 are attached to the fixed table 24, and the lens 4 is attached to the moving table 23. An eccentric convex portion 25 eccentric to the optical axis OA is provided, and an eccentric concave portion 26 into which the eccentric convex portion 25 is fitted is provided on the fixed base 24, and movement is achieved by fitting the eccentric convex portion 25 and the eccentric concave portion 26. The stand 23 is placed in a direction perpendicular to the optical axis OA of the lens 4 and the two light receiving areas 5 of the two-split photodetector 5 are
The lens 4 is moved and adjusted by rotating the moving table 23 in the direction in which the light receiving areas 5a and 5b are divided, and the light is received across the two light receiving areas 5a and 5b of the two-split photodetector 5. The light receiving image 7 is adjusted to a neutral point. Therefore, the lens 4 can be moved simply by rotating the movable base 23, and the rotation of the movable base 23 is caused by the rotation of the disc 2.
Since it can be done from the side below, the work of adjusting the light-receiving image 7 to the neutral point becomes extremely easy, and the work efficiency is greatly improved. Furthermore, the eccentric convex portion 25 of the moving table 23 and the eccentric recessed portion 26 of the fixed table 24 have extremely simple structures, and can be easily manufactured by integral molding, and the number of parts is small, so it is possible to reduce the cost of the device. can. In particular, the method of rotating the movable table 23 by eccentricity allows delicate adjustment of the light-receiving image 7, and the light-receiving image 7 can be adjusted to the neutral point with high accuracy.

Incidentally, the eccentric convex portion 25 and the eccentric concave portion 26 shown in the first embodiment may be formed in opposite directions on the movable table 23 and the fixed table 24, and it is also possible to reverse the fitting state. be. Furthermore, in the first embodiment, both the eccentric convex portion 25 and the eccentric concave portion 26 are arranged along the optical axis OA of the lens 4.
This is to make the outer diameters of the movable base 23 and the fixed base 24 the same, and in order to rotate the lens 4, at least the fitting part of the movable base 23 is aligned with the optical axis OA of the lens 4. All you have to do is make it eccentric to .

Next, FIGS. 13 to 16 show a second embodiment. In this second embodiment, the housing member of the skew detection device 1 includes a movable base 32 and a fixed base 3, as shown in FIGS. 13 to 15.
It is composed of 3. This moving table 32 has a substantially cylindrical shape, and the lens 4 is attached to the upper end side. Further, a light emitting diode 3 serving as a diffused light source and a two-split photodetector 5 are respectively attached to the upper surface side of the fixed base 33. Note that these lenses 4, light emitting diodes 3, and two-split photodetector 5
The positional relationship is the same as that described above.

The lower part of the movable table 32 is formed into a flat plate shape, and a slide part 34 consisting of a notch in a direction perpendicular to the optical axis of the lens 4 is formed on the lower end surface. On the other hand, on the upper surface side of the fixed base 33, on both sides of the light emitting diode 3 and the two-split photodetector 5, the two light-receiving areas 5a of the two-split photodetector 5 are arranged in a direction perpendicular to the optical axis OA of the lens 4, and A guide portion 35 consisting of a stepped portion along the direction in which the portion 5b is divided is formed. Note that the slide portion 34 and the guide portion 35 are the adjustment mechanism in the present invention. Therefore, as shown in FIG. 14, by fitting the slide portion 34 of the movable table 32 into the guide portion 35 of the fixed table 33, the movable table 32 is aligned with the optical axis of the lens 4.
It is configured to be slidable linearly relative to the fixed base 33 in a direction perpendicular to the OA, that is, horizontally while keeping the lens 4 on the same plane. Note that the position indicated by the imaginary line in FIG.
3 shows the state in which the optical axis OA of the lens 4 is moved to OA'' by sliding from the solid line state by △λ. Also, as shown in FIGS. 13 and 15, the fixed base 33, risers 36a and 36b are integrally formed at both ends in the direction in which the guide portion 35 is provided, and the riser 36a at one end has a screw hole 37, and the riser 36b at the other end has a guide hole 38. Further, on the outer circumferential surface of the movable table 32, a screw receiver 39 is provided on one end surface in the direction in which the slide portion is provided, and a guide rod 40 is provided on the other end surface.
is fixed. As shown in FIG. 15, the movable table 32 is fitted into the fixed table 33 with the guide rod 40 inserted into the guide hole 38. Note that the movable base 32 is biased to slide toward the adjustment screw 42 screwed into the screw hole 37 by a compression spring 41 inserted through the outer periphery of the guide rod 40, so that the screw receiver 39 of the movable base 32 is biased. Positioning is performed by contacting the tip of the adjustment screw 42.

According to the second example of the present invention configured as described above, the skew detection of the disk 2 by the skew detection device 1 is performed in the same manner as in the prior art. Therefore, the position of the light-receiving image 7 in the two light-receiving areas of the two-split photodetector 5 can be moved and adjusted very easily. Therefore, this principle will be explained with reference to FIG. 16.

That is, when the optical axis OA of the lens 4 and the recording surface of the disk 2 are perpendicular to each other as described above, the received light image 7 is the result of the two received lights of the two-split photodetector 5, as shown by the solid line. The same amount of light is received across regions 5a and 5b. When the movable table 32 is slid relative to the fixed table 33 by Δλ in the direction of arrow c, the lens 4 is moved linearly by Δλ to the position where the optical axis OA of the lens 4 is shown by the dashed line. Here, since the light-receiving image 7 on the two-split photodetector 5 can always be located at the opposite position (conjugate position) to the light-emitting diode 3 with respect to the optical axis OA of the lens 4, the light-receiving image 7 on the two-split photodetector 5 is Its center is 2・△λ
The lens 4 is linearly moved in the direction in which the optical axis OA of the lens 4 is moved by the amount of movement. Therefore, more of the light-receiving image 7 is included in one light-receiving region 5a side of the two-split photodetector 5, as shown by the dashed line. Further, when the movable table 32 is moved in the direction of the arrow d relative to the fixed table 33, the lens 4 is moved to the position shown by the two-dot chain line, contrary to the above, and due to the movement of the lens 4, the received light image 7 is As shown by the two-dot chain line, more light is contained on the other light-receiving region 5b side of the two-split photodetector 5.

By sliding the moving table 32 linearly with respect to the fixed table 33 in this manner, the position of the received light image 7 on the two-split photodetector 5 can be freely moved. Therefore, when the device is assembled, the position of the light-receiving image 7 on the two-split photodetector 5 is, for example, the light-receiving area 5a.
If it has shifted to the side, by sliding the moving table 32 in the direction of the arrow d, it is possible to correct the shift of the light-receiving image 7 and adjust it to the neutral point.

In addition, in order to slide the moving table 32 with respect to the fixed table 33, as shown in FIG.
All you have to do is turn 2, and the sliding movement is extremely easy.

As described above, in the second embodiment of the present invention, the lens 4 is attached to the movable table 32, the light emitting diode 3 and the two-split photodetector 5 are attached to the fixed table 33, and the slide part 34 is attached to the movable table 32. The fixed base 33 is provided with a guide part 35 into which the slide part 34 is fitted, and the slide part 34 and the guide part 35 are connected to each other.
By fitting the movable table 32 with the optical axis OA of the lens 4,
2 of the two-split photodetector 5 in a direction perpendicular to
The two light-receiving regions 5a, 5b of the two-split photodetector 5 are divided into two light-receiving regions 5a, 5b by sliding the lens 4 linearly in the direction in which the two light-receiving regions 5a, 5b are divided. The light-receiving image 7, which is received across the two directions, is adjusted to a neutral point. Therefore, the lens 4 can be moved simply by sliding the movable base 32, and since the movable base 32 can be slid from the side below the disk 2, the received light image 7 can be adjusted to the neutral point. The work becomes extremely easy and the work efficiency is greatly improved. Furthermore, the slide portion 34 of the moving table 32 and the guide portion 35 of the fixed table 33 have an extremely simple structure, and can be easily manufactured by integral molding, and the number of parts is small, so the cost of the device can be reduced. .

Note that the slide portion 34 and guide portion 35 shown in the second embodiment are not limited to the shapes described above, and various effective linear movement structures can be used.

Although the embodiment of the present invention has been described above, the tonality mechanism referred to in the present invention is not limited to the structure shown in this embodiment, and various other effective structures can be used.

[Application Example] The skew detection device for an optical disk device according to the present invention can be applied as a device for video disks, audio disks, and various other information processing disks. Furthermore, the present invention is not limited to a disc playback device, but can also be applied as a disc recording device.

[Effect of the invention] The present invention mounts a diffused light source and a two-split photodetector on a fixed base, and divides at least two light-receiving areas of the two-split photodetector in a direction perpendicular to the optical axis of the lens. A movable base is provided that is movable in a direction, a lens is attached to the movable base, and an adjustment mechanism is provided to adjust the movement of the movable base with respect to the fixed base.
By moving and adjusting the lens using this adjustment mechanism, the light-receiving image received across the two light-receiving areas of the two-split photodetector is adjusted to a neutral point.

Therefore, according to the present invention, the received light image can be adjusted to the neutral point simply by moving and adjusting the lens using the moving table, making this adjustment work extremely easy and greatly improving work efficiency. . Furthermore, since the adjustment mechanism has an extremely simple structure and the number of parts is small, the cost of the device can be reduced.

[Brief explanation of the drawing]

1 to 8 show a conventional skew detection device for an optical disk device, in which FIG. 1 is a plan view, FIG. 2 is a vertical cross-sectional view as seen from the radial direction of the disk, and FIG. The figure is a longitudinal cross-sectional view of the disk viewed from the track direction, Figure 4 is a perspective view of the diffused light source and two-split photodetector, Figure 5 is a schematic diagram explaining the principle of reception of diffused light, and Figure 6 is a received light image. 7 is a side view illustrating the deviation of the received light image, and FIG. 8 is an exploded view showing an example of the swing mechanism for making the optical axis of the optical pickup perpendicular to the disk. FIG. 9 to 16 show a skew detection device for an optical disk device to which the present invention is applied. First of all, Figures 9 to 12 are the first
Fig. 9 is an exploded perspective view, Fig. 10 is a vertical sectional view of the disk in the assembled state as seen from the radial direction, and Fig. 11 is an XI of Fig. 10.
A sectional view along the -XI line and FIG. 12 are plan views illustrating movement of the received light image. Also, Figures 13 to 16
The figures show the second embodiment, in which Fig. 13 is an exploded perspective view, Fig. 14 is a longitudinal cross-sectional view of the disk in the assembled state seen from the radial direction, and Fig. 15 is the same as above, showing the track of the disk. Longitudinal cross-sectional view seen from the direction,
FIG. 16 is a plan view illustrating the movement of the received light image. In addition, in the symbols used in the drawings, 1...
Skew detection device, 2... disk, 3... light emitting diode as a diffused light source, 4... lens, 5...
... Two-split photodetector, 5a, 5b... Two light receiving areas, 7... Light receiving image of diffused light source, 23... Moving table,
24...Fixing base, 25...Eccentric convex portion which is an adjustment mechanism, 26...Eccentric recess which is an adjustment mechanism, 32...
A movable table, 33...a fixed table, 34...a slide portion which is an adjustment mechanism, 35...a guide portion which is an adjustment mechanism, and OA...an optical axis of a lens.

Claims (1)

[Scope of utility model registration request] It consists of a lens, and a diffused light source and a two-split photodetector arranged on the same focal plane of the lens and distributed in a direction perpendicular to the optical axis of the lens, and the diffused light from the diffused light source is The recording surface of the optical disk is irradiated by a lens, and the reflected light is received by the lens across two light-receiving areas of the two-split photodetector, and a light-receiving image in the two light-receiving areas is created. In the skew detection device of the optical disk device configured to detect the direction and amount of skew of the optical disk based on the difference in the detection output of Attachment: Providing a movable stage that is movable in a direction perpendicular to the optical axis of the lens and at least in a direction in which the two light-receiving areas of the two-split photodetector are divided, and mounting the lens on the movable base. , an adjustment mechanism for moving and adjusting the movable table with respect to the fixed table is provided, and by adjusting the movement of the lens by this adjustment mechanism, light is received across the two light receiving areas of the two-split photodetector. A skew detection device for an optical disk device, characterized in that the device is configured to adjust a received light image to a neutral point.