JPH0376030A - Optical information recording and reproducing device - Google Patents

Abstract

PURPOSE:To perform the seek for a target track within a short time and to prevent dust from getting in an optical pickup by providing a counterbalance for hermetically sealing the bottom of a carriage in which optical parts are incorporated so that the center line of driving, the center of a guide rail and the centroid point of a movable member may be nearly coincident. CONSTITUTION:The counterbalance is provided on the bottom part of the carriage 6 on which the optical pickup 2 housing the optical parts is mounted, for example, at the symmetric position of the center of axis of a two-dimensional actuator 4 in an up-and-down direction so that the centroid point of the entire carriage 6 may be allowed to coincide with the center line of driving and the center line of the guide rail. By sealing the opening part of the adjusting mechanism, etc., of the optical parts with the aid of the counterbalance, the means for preventing the dust from getting in the optical pickup 2 is constituted. Thus, excitation is controlled and the seek of the target track is performed within a short time, then an adverse effect on recording and erasing, etc., caused by the dust adhering to the optical parts in the optical pickup 2 is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an optical information recording/reproducing device in which the bottom surface of a carriage containing an optical element is sealed.

[Prior Art] In recent years, optical information recording and reproducing devices such as magneto-optical systems have been put into practical use, which use optical heads instead of magnetic heads to record and reproduce information at high density. Ta.

For example, Japanese Utility Model Application No. 63-66328 proposes an optical recording/reproducing apparatus as shown in FIG.

In this device 1, the optical pickup 2 includes an objective lens 3.
A two-dimensional actuator 4 for moving the objective lens 3 in two-dimensional directions for focusing and tracking is provided upright, and a flexible substrate 5 is provided on the top surface of the optical pickup 2. The upper surface has a nearly sealed structure.

On both sides of the carriage 6 on which the optical pickup 2 is mounted, a voice coil 7 is loosely passed through a yoke 8 via a bobbin 9, and a magnetic circuit is provided with a magnet 11 or the like, and a current can be passed through the coil 7. A voice coil motor 13 is formed in which the carriage 6 is movable along the guide rail 12.The voice coil motor 13 allows the optical pickup 2 to be moved in the direction across the track, so that it can be moved to any desired track. making it accessible.

The carriage 6 has a guide rail 12 passed through a guide hole.
12 to guide rollers 14, 14. ... supports it in a movable manner.

The optical pickup 2 includes a high frequency module (hereinafter abbreviated as FM) 15 for reducing noise generated by the laser light emitted by the laser diode and the return light from the disk, and a high frequency module (hereinafter abbreviated as FM) 15 that receives the return light from the disk. A photodetector 16 that generates a reproduction signal, a monitor photodetector 17 that monitors the amount of light emitted from the laser diode, a servo control photodetector 18 that generates control signals for focusing and tracking with the actuator 4, and the like are provided. It is.

Note that a sensor 19 is provided within the actuator 4 to detect the position of the objective lens 3 in the tracking direction.

By the way, in the device 1, for example,
An optical system 20 as shown in FIG. 7 proposed in No. 952 is housed to constitute an information recording/reproducing device (of magneto-optical type).

As shown in FIG. 7, a laser diode 21 as a light source is housed in the housing of the magneto-optical optical pickup 2, and the diffused light of, for example, P-polarized light emitted from the laser diode 21 is transmitted to a collimator. lens 22
It is designed to be made into a parallel beam of light. This parallel light beam is obliquely incident on the prism 23. This light flux enters the beam splitter 24, part of which is reflected, and the rest transmitted, and then the optical path is changed in the right angle direction by the total reflection mirror 25 (
In FIG. 7, the light is focused on a disk (not shown) by an objective lens 3.

Note that the reflected light from the beam splitter 24 is made incident on a monitor photodetector 17 for performing automatic power control (APC) through a lens 26.

The reflected light from the recording layer of the disk (not shown) is converted into a parallel beam by the objective lens 3, and is converted into a parallel light beam by the total reflection mirror 2.
After being reflected by the beam splitter 5, the beam is incident on the beam splitter 24. The incident light is reflected by the beam splitter 24, further reflected by the incident surface of the prism 28, and then reflected by the lens 3.
It is designed to be incident on 1.

The prism 28 transmits a part of the reflected light, and the light path is changed by 90° and the light is emitted to the critical angle prism 32 . This critical angle prism j2 is designed to allow a light beam to enter a control four-split photodetector 18 that performs focusing and the like.

The light beam reflected by the prism 28 is made into parallel light by a lens 31 and a lens 33, and then enters a polarizing beam splitter (hereinafter abbreviated as PBS) 34. This PBS 34 is provided so that the polarization axis of the incident light is tilted by 45°.

As shown in FIG. 8, the PBS 34 is constructed such that one of the optical media 37a and 37b, such as glass, is a triangular prism whose cross section is a right triangle, and the other is a quadrangular prism whose cross section is a parallelogram. A dielectric thin film 38 is formed and integrated.

Of the light incident on the PBS 34, the P polarized light passes through the dielectric thin film 38 and travels in the same direction as the incident light;
After the polarized light is reflected by the dielectric thin wA38, the optical fitj
The light reaches a reflecting surface 39, which is formed by a mirror 37b and has an angle of 45° with respect to the incident light, for example.

At this time, if the refractive index n of the optical medium 37b is n=1.5, the angle of incidence on the reflecting surface 39 is larger than the critical angle, so it is totally reflected and the reflected light is transmitted in the same direction as the incident light at a position translated by a distance ll1a. can get.

In the optical path of the transmitted light and reflected light of the PBS 34, a reproduction photodetector 16, which is divided into two, for example, is disposed, and converts the transmitted light and reflected light into electrical signals. This photodetector 16
is electrically connected to a differential amplifier (head amplifier) not shown, and extracts the strength of transmitted light and reflected light as electrical signals.

The above lenses 31, 33, PBS 34 and reproduction photodetector 3
6 is housed in a lens frame 41 shown in FIG.

The lens frame 41 is made of a hard material and has a cylindrical shape, and is provided with seven flange portions 42 at its rear end. Inside this lens frame 41, a light guide path that coincides with the rotation axis of this lens frame 41 is provided. The lens 31 is fixed to the incident end side (front end side) of this light guide path,
Furthermore, the lens 33 is fixed near the center. Further, on the outer circumferential surface of the lens frame 41, in the vicinity of the front end side of the seven flange portion 42, a groove portion 44 that reaches the light guide path is provided. It is inserted so that a light beam made into parallel light by .33 is input thereto, and P-polarized light and S-polarized light can be emitted from the rear end surface side.

The monitor photodetector 16 is provided behind the PBS 34 so that its rear end surface substantially coincides with the rear end surface of the lens frame 41, and is capable of receiving the P-polarized light and the S-polarized light. Furthermore, a substrate 46 is attached to the rear end surfaces of the monitor photodetector 16 and the lens frame 41 so as to press down the monitor photodetector 16.

In FIG. 9, each component is assembled to the lens frame 41 by fixing the lenses 31 and 33 within the light guide path of the lens frame 41, which has been machined with high dimensional accuracy, and
S34 is fixed in the groove 44 by interlocking it. At this time, the groove 4
4 and the light guide path are machined to a high degree of dimensional accuracy, so there is no possibility that the optical axis will shift.

Thereafter, the monitor photodetector 16 is attached to the rear of the PBS 34, and the substrate 46 is further attached to the rear end surface of the lens frame 41.

In addition, the lens frame 41 in which each of the above-mentioned optical components is incorporated is as follows:
It is inserted into a housing (not shown) of the optical pickup 2.

The back side of the carriage 6 to which the optical pickup 2 containing each optical component constituting the optical system 20 is attached is as shown in FIG. 10, for example.

Further, its front view is shown in FIG. 11.

In addition, in FIG. 11, the guide rail 12 is shown passing through.

As shown in FIG. 11, the structure of the carriage 6 in which the optical pickup 2 is built is that the line connecting the guide rail center axis and the two voice coils 7.7, that is, the drive action line (drive center line), is a straight line. It is arranged as shown above.

[Problems to be Solved by the Invention] However, since the weight and size of the two-dimensional actuator 4 are large, the center of gravity in the vertical direction does not coincide with the line of action of the drive and the central axis of the guide rail, and the actuator 4 and the guide rail 12. 12 or the guide roller 14. The distance (difference in height) between the guide roller 14 and the 14 portion becomes large.

For this reason, for example, due to the tracking operation of the actuator 4, the side of the carriage 6 is relatively vibrated, which hinders the smooth movement of the carriage 6 along the center axis of the guide rail, and it takes time to seek to the target track. The disadvantage is that it takes a lot of time.

Furthermore, as shown in the bottom view of FIG.
3. Dust flows into the optical pickup 2 through the five openings in the optical prism surface exposed portion 54 and the servo control detector board 55 portion, and the dust adheres to the optical components in the optical pickup 2, causing the objective lens 3 A drawback arises in that the amount of light emitted from the top is insufficient, making it difficult to write or erase information.

In addition, in FIG. 10, a pressing member 57 is provided near the rotation adjustment mechanism 51. Further, in this figure, the opening around the guide shaft pressing roller 58 does not communicate with the optical component storage portion of the optical pickup 2.

On the other hand, if the bottom surface of the carriage 6 containing the optical pickup 2 is structured so that various adjustment mechanisms are not exposed, the structure of the carriage 6 becomes complicated, and furthermore, there is a problem in that it is difficult to make adjustments.

In Japanese Patent Application No. 1-113123, a weight is provided on the optical pick-up or the carriage to control vibration even when the actuator is operated. However, this prior art does not prevent dust from entering the optical pickup.

The present invention has been made in view of the above-mentioned points, and it is an object of the present invention to provide an optical information recording/reproducing device that can seek to a target track in a short time and can prevent dust from flowing into an optical pickup. .

[Means and effects for solving the problem] In the present invention, a counterbalance is provided on the bottom of the carriage on which the optical pickup containing the optical components is mounted, for example, at a symmetrical position with respect to the vertical axis of the actuator. By aligning the center of gravity of the entire carriage with the center line and the center line of the guide rail, and by sealing the openings of the adjustment mechanisms of the optical components, etc., with a counterbalance, a means for preventing dust from entering the optical pickup is constructed. By doing so, it is possible to suppress the vibration υ1 and enable short-time seeking to the target track, and also to prevent dust from adhering to the optical components in the optical pickup, which would adversely affect recording, erasing, etc. It is prevented.

[Example] Hereinafter, the present invention will be specifically explained with reference to the drawings.

FIGS. 1 to 4 relate to a first embodiment of the present invention.
The figure shows the bottom view of the carriage in the first embodiment without the counterbalance installed, FIG. 2 shows the counterbalance installed in FIG. 1, and FIG. 3 shows the first embodiment with the counterbalance installed. A side view of the figure is shown, and FIG. 4 shows an optical system for magneto-optical reproduction.

The magneto-optical optical information recording and reproducing device of the first embodiment is as follows:
Its outer shape is almost the same as the device 1 shown in FIG. 6, and its perspective view is omitted.

Moreover, in the optical system of this equipment, many of the optical parts are built in the rotating holder in the optical system shown in FIG. 7, so the lead wire from the photodetector 16 to the head amplifier (not shown) is long. Since the deterioration of the detected signal cannot be ignored, the substrate 50 provided with the photodetector 16 is fixed to the main body of the carriage 6 in this embodiment. Furthermore, the single lenses 31 and 33 in FIG. 7 are replaced with a single lens 31' made of a single convex lens, which is bonded to the end face of the prism 24 as shown in FIGS. 4 and 1, so that only the PBS 34 can be rotated. ing. The bottom surface of the carriage 6 in this embodiment is as shown in FIG. 1, and has the same structure as that shown in FIG. 7 except for the peripheral portion where the single lens 31 is joined to the prism 24.

Therefore, in this state, as in the conventional example, the rotation adjustment mechanism 51, front monitor photodetector board 52, critical angle prism adjustment groove 53, optical prism surface exposed portion 54, and servo control detector board 55 are The opening is exposed (the bottom of the actuator 4 is closed).

The first feature of the first embodiment is that these openings are covered with a counterbalance 64 having a shape as shown in FIG.

This counterbalance 64 is pasted on the entire one side of the counterbalance 64 via an adhesive at a position shown by the dotted line on the bottom surface of the carriage 6 in FIG.

The counterbalance 64 may be a plate made of a metal material such as aluminum or brass, or a sheet plate made of plus deck material.

In addition, by mounting the counterbalance 64 so that its center of gravity becomes the center axis of the actuator 4, the drive center line p and the guide rail center axis (2) are aligned as shown in FIG.
The mounting of the counterbalance 64 is determined by position, size and [1
The second feature is that the center of gravity of the entire carriage 6 is set below O on the center line m of the actuator 4 unless the counterbalance 64 is installed (see Fig. 3). (in the case of ), it becomes the actuator 4 side).

According to this first embodiment, the opening in the bottom of the carriage 6 that communicates with the optical components in the optical pickup 2 is sealed with the counterbalance 64, and the position of the center of gravity of the entire carriage is adjusted due to the ff1l of the two-dimensional actuator 4. The center of gravity is shifted to the actuator 4 side from the drive center line or the plane including the guide rail 12.12 by using a counterbalance 64 to shift the center of gravity so that it is on the same plane and coincides with the intersection with the center axis of the actuator 4. By doing so, even if the actuator 4 is operated to perform tracking or the like, relative vibration between the carriage 6 and the actuator 4 is suppressed, and it becomes possible to seek to the target track in a short time. . Further, by adhering dust and the like around the optical components to the adhesive portion exposed inside each opening, it is possible to improve the cleanliness of the air inside the optical pickup.

I! FIG. 5 shows a counterbalance 71 attached to the bottom surface of the carriage 6 in a second embodiment of the present invention.

In this second embodiment, a weight 72 is attached to the bottom surface of the carriage 6 via an elastic material 73. This elastic material 73 provides a dynamic vibration absorber function for absorbing vibrations. Other functions are similar to those in the first embodiment.

Alternatively, the elastic material 73 itself may be formed of an adhesive, and a tab 72 made of a metal material such as aluminum or brass may be attached to the adhesive and affixed to the carriage 6 (adhesive).

Alternatively, the opening at the bottom of the carriage sealed by the counterbalance may be made larger to increase the dust removal ability of the adhesive portion exposed inside the opening.

Further, in the first embodiment or the second embodiment, the counterbalances 64, 71 may be attached to the bottom surface of the carriage 6 using screws or the like.

Furthermore, a counterbalance made of transparent plastic material is attached to the carriage so that the adhesive is exposed at least on the inside of the opening, so that the degree of dust that has adhered to the adhesive due to long-term use can be seen, and if necessary, It may be replaced.

It is clear that the present invention is not limited to magneto-optical optical information recording and reproducing apparatuses, but can be widely applied to other optical information recording and reproducing apparatuses that form bits and the like.

[Effects of the Invention] As described above, according to the present invention, the openings in the bottom surface of the carriage leading to the housing in which the optical components constituting the optical pickup are built are sealed by the counterbalance, and the actuator is closed by the counterbalance. Since the entire center of gravity of the carriage including the carriage is made to coincide with the center of the drive center line, relative vibration of the carriage is suppressed even when the actuator is operated.
In addition, it is possible to perform a smooth seek operation, and it is also possible to prevent dust from adhering to the optical components of the optical pickup, thereby preventing problems with recording, erasing, etc.

[Brief explanation of drawings]

FIGS. 1 to 4 relate to a first embodiment of the present invention.
The figure shows a bottom view of the carriage in the first embodiment, FIG. 2 shows a counterbalance attached to the bottom of the carriage, FIG. Figure 1 is a front view through the guide rail, Figure 4 is a configuration diagram of the optical system of the optical pickup, and Figure 5 is a diagram showing the configuration of the optical system of the optical pickup.
The figure is a front view of a carriage in a second embodiment of the present invention.
6 to 11 relate to conventional examples, FIG. 6 is a perspective view of the conventional example, FIG. 7 is a configuration diagram showing the optical system of the optical pickup, and FIG. 8 is an enlarged view of the beam splitter portion in FIG. 7. 9 is a perspective view showing the lens frame, FIG. 10 is a bottom view of the carriage, and FIG. 11 is a front view of FIG. 10. 2... Optical pickup 3... Objective lens 4...
・(Two-dimensional) actuator 6... Carriage 7... Voice coil 12
...Guide rail 15...HFM16...Photodetector for reproduction 17...Monitor photodetector 18...Servo II Jill photodetector 31'...Single lens
51...Rotation adjustment mechanism 52...Front monitor photodetector board 54...Optical prism surface exposed portion 55...Servo control photodetector board 64...Counter balance Fig. 3 Fig. 4 Fig. 1 (b) Fig. 2 (0) Fig. 5 Fig. 7 Fig. 8 Fig. 6 Fig. 10 Fig. 11 Procedural summary (spontaneous) 1. Indication of the incident 1999 Patent Application No. 212085 2. Invention Name Optical information recording and reproducing device 3, relationship with the person making the amendment case

Claims (1)

[Scope of Claims] 1. An optical information recording and reproducing device equipped with a voice coil type optical pickup moving device that moves a movable member with built-in optical components by passing current through the voice coil, which includes built-in optical components. 1. An optical information recording/reproducing device characterized in that a counterbalance for sealing the bottom surface of a carriage is provided so that a driving center line, a center of a guide rail, and a center of gravity of a movable member substantially coincide with each other. 2. The optical information recording and reproducing apparatus according to claim 1, wherein the counterbalance has a dynamic absorber structure to which a weight is attached via an elastic member.