JPH0492217A - Position detector - Google Patents

Abstract

PURPOSE:To reduce the weight of a mobile cabinet by providing a first sensor which detects an optical mark and a second optical sensor which detects no optical mark while an optical pickup device detects an effective recording area. CONSTITUTION:The output signal S1 of an optical sensor 30 goes to a high level since the optical sensor 30 detects the lower plane of the mobile cabinet 2 by moving the mobile cabinet 2 in the radius direction of an optical storage medium 7 when detecting a terminal part PA at an inner peripheral side in the effective recording area of the medium 7 to a terminal part PB at the outer peripheral side. Also, the output signal S2 of the optical sensor 31 goes to a low level when the optical pickup device is located in the central position of the effective recording area i.e. a position at the peripheral side inner than a home position HP, and the signal S2 goes to the high level when it is located at the peripheral side outer than the HP. Thereby, it is possible to decide the deviation of the movable range of the optical pickup device from the effective recording area by monitoring the signal S1.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a position detection device for detecting the radial position of an optical storage medium of an optical pickup device for recording and reproducing data on the optical storage medium.

[Conventional technology] Generally, optical disks and magneto-optical disks (hereinafter referred to as optical disks)

An optical pink-up device for recording and reproducing data on (collectively referred to as an optical storage medium) uses a traveling body that reciprocates in the radial direction of the optical storage medium so that the entire recording area of the optical storage medium can be accessed. It is installed in.

Furthermore, if the entire optical pickup device is mounted on a vehicle and moved, the weight of the vehicle increases, which hinders miniaturization of the device and makes it difficult to achieve high-speed data access. .

Therefore, in an optical pickup device, the objective lens that images the signal light onto the optical storage medium is separated from the other optical systems, and only that objective lens is mounted on the traveling body, making it possible to achieve high-speed data access. There is something like this,
Conventional examples thereof are shown in FIGS. 5(a), (b), and (c).

In the figure, an objective lens 1 and an objective lens moving mechanism (path shown) that moves the objective lens in the tracking direction and the focusing direction are mounted on a moving housing 2, and the other optical system components of the optical pickup device are , housed in the fixed housing 3. deflection prism 4
is for deflecting the optical axis of the optical system housed in the fixed housing 3 toward the objective lens 1.

The movable housing 2 is supported by a base member 6 by a support member 5, and linear motors 8 and 9 are mounted on both sides of the base member 6 for reciprocating the movable housing 2 in the radial direction of the optical storage medium 7.
is provided.

An encoder plate 10 of a position detection device for detecting the movement range of the movable casing 2 is connected to the movable casing 2 via a support member 11.
The encoder plate 10 has a reflective surface on its back side, and is set to have a dimension slightly larger than the radial dimension TA of the effective recording area of the optical storage medium 7. transparent part 12 and transparent part 1
A transmissive portion 13 is formed that extends from 2 1/2 to the outside of the effective recording area on the outer circumferential side of the optical storage medium 7.

a reflective optical sensor 15 that detects the transparent part 12; and
A reflective optical sensor 16 that detects the transparent portion 13 is fixed to the base member 6 via a member 17. Further, the optical sensor 15 and the optical sensor 16 are operated at the center of the transparent section 12 and the inner periphery of the transparent section 13, respectively, while the optical pickup device is moved to the center position of the effective recording area of the optical storage medium 7. Its position is set to detect the side edge.

Further, the spindle motor 18 is for rotating the optical storage medium 7, and the turntable 19 is for transmitting the rotational force of the spindle motor 18 to the optical storage medium 7.

With the above configuration, when the movable housing 2 is moved in the radial direction of the optical storage medium 7, as shown in FIGS. 6(a) and (b),
When the optical pickup device is detecting the effective recording area of the optical storage medium 7 from the inner end PA to the outer end PB, the output signal SA of the optical sensor 15 is at a low level, and the effective recording area is When the optical sensor 15 is located at a portion away from the optical sensor 15, the output signal SA of the optical sensor 15 becomes high level.

In addition, the optical pickup device is located at the center of the effective recording area,
That is, when the optical pickup device is located on the inner circumferential side of the home position HP, the output signal SB of the optical sensor 16 becomes a low level, and the optical pickup device returns to the home position 11.
When the optical sensor 16 is located on the outer circumferential side than P, the optical sensor 16
The output signal SB of becomes high level.

In this way, by monitoring the output signal SA of the optical sensor 15, it is possible to determine whether the optical pickup device is moving out of the effective recording area, and also by monitoring the output signal SB of the optical sensor 16. By checking, it can be determined whether the optical pickup device is located at the home position.

Therefore, for example, when the linear motors 8 and 9 run out of control when a large disturbance such as a shock is applied from the outside, or when the focusing and tracking of the optical pickup device are lost due to a defect in the optical storage medium 7,
When the optical pickup device leaves the effective recording area, the signal SA changes to a high level.

Thereby, by stopping the supply of drive current to the linear motors 8 and 9, it is possible to avoid a situation in which the movable housing 2 collides with the fixed housing 3, the spindle motor 18, or the like.

Furthermore, the direction in which to move to the home position HP can be determined based on the level of the signal SB, and by stopping the moving housing 2 at the timing when the level of the signal SB changes, the optical pickup device can be positioned at the home position HP. I can do it.

[Problems to be Solved by the Invention] However, such conventional devices have the following disadvantages.

That is, since the encoder plate 10 is attached so as to protrude outward from the movable housing 2, the dimension in the direction orthogonal to the moving direction of the movable housing 2 becomes large, and the optical disk drive device or magneto-optical disk unloading device This was an impediment to miniaturization.

The encoder plate 10 also has two transparent parts 12 and 13.
As a result, the size of the encoder plate 10 becomes large, and the weight of the movable housing 2 increases, which hinders an increase in data access speed.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a position detection device for an optical pickup device that can eliminate the disadvantages of the conventional device, reduce the size of the drive device, and reduce the weight of the moving casing.

[Means for Solving the Problems] The present invention provides an optical mark that is provided on a movable part of an optical pickup device and is set to be larger than at least the radial dimension of an effective recording area of an optical storage medium; A first optical sensor that detects the optical mark while detecting the effective recording area; and a second optical sensor that does not detect the optical mark when the optical pickup device is located at the reference position of the effective recording area. It is equipped with a sensor.

[Function] Therefore, the moving range of the optical pickup device and the home position can be detected using the same optical mark, so the weight of the moving housing can be reduced.

Further, since the dimension in the direction perpendicular to the moving direction of the optical pickup device can be reduced, it is possible to contribute to miniaturization of the drive device.

[Example] Hereinafter, an example of the present invention will be described in detail with reference to the accompanying drawings.

FIGS. 1(a), 1(b), and 1(c) show an optical pickup device according to an embodiment of the present invention. In addition, in these figures, Fig. 4 (a), (b), (
The same or corresponding parts as c) are given the same reference numerals.

In the figure, the dimension of the movable housing 2 in the moving direction is set to a value slightly larger than the radial dimension TA of the effective recording area of the optical storage medium 7, and the lower surface of the movable housing 2 is formed as a reflective surface. ing. Here, since aluminum or aluminum alloy is used as the material for the movable housing 2, a reflective surface can be formed by polishing the lower surface of the movable housing 2.

Two reflective optical sensors 30 and 31 are disposed on the base member 6 at positions where the lower surface of the movable housing 2 can be detected. The optical sensor 30 uses an optical pickup device as an optical storage medium 7.
When moving to the center position of the effective recording area of , the optical sensor 31 is placed in a position where the center position of the movable housing 2 can be detected. They are respectively disposed at positions shifted in the radial direction of the optical storage medium 7 by a distance of dimension 172.

Therefore, when the movable housing 2 is moved in the radial direction of the optical storage medium 7, as shown in FIG. When detecting up to the end PB, the optical sensor 3
0 detects the bottom surface of the movable housing 2.
), the output signal S1 of the optical sensor 30 becomes high level, and when the optical pickup device detects a portion outside the effective recording area, the output signal S1 of the optical sensor 30 becomes high level.

In addition, the optical pickup device is located at the center of the effective recording area,
That is, when the optical sensor 31 is located on the inner circumferential side than the home position FIP, the optical sensor 31 detects the lower surface of the movable housing 2, so as shown in FIG. 3(b), the output of the optical sensor 31 is When the signal S2 is at a low level and the optical pickup device is located on the outer circumferential side of the home position IIP, the output signal S2 of the optical sensor 31 is at a high level.

Thereby, by monitoring the output signal Sl of the optical sensor 30, it is possible to determine whether the movement range of the optical pickup device has deviated from the effective recording area.

Also, by checking the output signal S2 of the optical sensor 31.

It is possible to monitor the direction in which the optical pickup device is moved to the home position HP and whether the optical pickup device is located at the home position HP.

Therefore, for example, when the linear motors 8 and 9 run out of control when a large disturbance such as a shock is applied from the outside, or when the focusing and tracking of the optical pickup device are lost due to a defect in the optical storage medium 7,
When the optical pickup device leaves the effective recording area, the signal S1 changes to a low level.

Thereby, by stopping the supply of drive current to the linear motors 8 and 9, it is possible to avoid a situation where the movable casing 2 collides with the fixed casing 3 or the spindle motor 18.

Furthermore, the direction in which to move to the home position HP can be determined based on the level of the signal S2, and by stopping the moving housing 2 at the timing when the level of the signal S2 changes, the optical pickup device can be positioned at the home position HP. I can do it.

As described above, in this embodiment, the lower surface of the movable casing 2 is shaped into a reflective surface, and this reflective surface is detected by the optical sensors 30 and 31, so that the position of the movable casing 2 can be detected. The driving device can be miniaturized without the elements protruding from both sides of the movable housing 2.

Furthermore, since no elements for position detection are attached to the movable casing 2, it is possible to prevent the weight of the movable casing 2 from increasing, making it possible to move the movable casing 2 at high speed, and to access data from the optical pickup device. The speed can be increased.

FIGS. 4(a) and 4(b) show an optical pickup device according to another embodiment of the present invention. In these figures, the same or corresponding parts as in FIGS. 1(a) and 1(b) are designated by the same reference numerals.

In the figure, the movable housing 2 is provided with a supporting member 33.
A long reflecting member 34 whose longitudinal dimension is set to be slightly larger than the radial dimension TA of the effective recording area of the optical storage medium 7 is arranged with its longitudinal direction along the moving direction of the movable housing 2. in the manner in which it was done.

attached.

A reflective member 3 is attached to the base member 6 via a holding member 35.
Optical sensors 30 and 31 are arranged at positions where they can detect 4.

Therefore, when the optical pickup device is detecting the effective recording area of the optical storage medium 7 from the inner end PA to the outer end PB, the optical sensor 30 is detecting the reflective member 34. Similar to the embodiment described above, when the output signal S1 of the optical sensor 30 becomes high level and the optical pickup device detects a portion outside the effective recording area, the output signal S1 of the optical sensor 30 becomes high level. Become.

In addition, the optical pickup device is located at the center of the effective recording area,
That is, when the optical sensor 31 is located on the inner circumferential side than the home position HP, the optical sensor 31 detects the reflective member 34, so the output signal S2 of the optical sensor 31 becomes a low level, as in the above-mentioned embodiment. Therefore, when the optical pickup device is located on the outer circumferential side of the home position HP, the output signal S2 of the optical sensor 31 becomes high level.In this way, in this embodiment, the optical sensor 31 is Since the detection operations 30 and 31 are performed, the weight of the elements of the position detection device provided in the movable housing 2 can be reduced, and high-speed movement of the movable housing 2 can be realized.

In the above-described embodiments, a reflection type optical sensor is used, but a transmission type optical sensor may also be used.

[Effects of the Invention] As explained above, according to the present invention, the moving range and home position of the optical pickup device can be detected using the same optical mark, so the weight of the moving housing can be reduced. Can be reduced.

Further, since the dimension in the direction perpendicular to the moving direction of the optical pickup device can be reduced, an effect can be obtained that contributes to miniaturization of the drive device.

[Brief explanation of the drawing]

FIG. 1(a) is a plan view showing an optical pickup device according to an embodiment of the present invention, FIG. 1(b) is a front partial cross-sectional view of the same,
Figure (c) is a partial sectional view of the same side, and Figure 2 is Figure 1 (a).
, (b) and (c) are schematic diagrams showing the mode of position detection of the device, FIG. 3 is a waveform diagram showing an example of changes in the position detection signal, and FIG. FIG. 5(b) is a plan view showing an optical pickup device according to an embodiment of the present invention, FIG. 5(b) is a front partial sectional view thereof, and FIG. FIG. 6b) is a front partial sectional view of the same, FIG. 6(c) is a side partial sectional view of the same, and FIGS. 2... Mobile housing, 30.31... Optical sensor, 33
... Supporting member, 34... Reflecting member, 35... Holding member.

Claims (1)

[Claims] In a position detection device for detecting the radial position of an optical storage medium of an optical pickup device for recording and reproducing data on the optical storage medium, the position detection device is provided on a movable part of the optical pickup device and detects at least the effective recording area of the optical storage medium. an optical mark set larger than the radial dimension; a first optical sensor configured to detect the optical mark while the optical pickup device detects the effective recording area; A position detection device comprising a second optical sensor that does not detect the optical mark when located at a reference position in a recording area.