JPH0652568A - Driving device for objective lens - Google Patents

Abstract

PURPOSE:To make the recording and reproduction performed by using a laser beam more accurate by forming an air-conditioning section for blowing air having an inlet on the external wall side of a protective cover communicated with an outlet. CONSTITUTION:When an optical pickup section 20 is moved in the radial direction (Y-axis direction) of an optical disk 16, air flows into an air-conditioning section 18 from an inlet side 19b and the air is discharged from an outlet 19a formed on the surface of an objective lens 10 after passing through the section 18 as shown by the arrow. As a result, dust deposited on the surface of the lens 10 can be blown off. Therefore, the surface of the lens 10 can be always maintained in a clean state and, at the same time, the recording and reproduction performed by using a laser beam can be improved in accuracy.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to the optical recording of information,
In an optical information recording / reproducing apparatus for reproducing, it relates to an objective lens driving apparatus for driving and controlling an objective lens for focusing a laser beam on a disc-shaped information recording medium.

[0002]

2. Description of the Related Art As a conventional objective lens driving device, for example, there is one disclosed in JP-A-4-14631 under the title "Objective lens driving device". Therefore, an example of the objective lens driving device is now shown in FIG.
It will be described based on. The objective lens 1 is held by an objective lens holding body 2, and the outside thereof is covered by an actuator cover 3. The actuator cover 3 is fixed to the upper part of the optical pickup section 5 by a base 4 provided on the bottom surface thereof. Objective lens 1
An opening window 6 is formed in the upper actuator cover 3, and an opening window 7 for communicating with the optical pickup unit 5 is also formed in the base 4 below the objective lens 1.

In such a structure, a beam emitted from a laser light source (not shown) in the optical pickup section 5 travels through the opening window 7 to a position above the objective lens 1 and is collected by the objective lens 1. The emitted beam is emitted to the outside through the opening window 6 and is irradiated onto the recording surface of the optical disc 8 serving as an information recording medium, whereby information can be recorded and reproduced.

[0004]

In the above-mentioned device, dust in the air is blown up by the air flow 9 generated by the rotation of the optical disk 8, and the dust thus blown through the opening window 6 by natural fall. It invades inside (in the direction of the arrow in FIG. 4) and is gradually deposited on the surface of the objective lens 1. Further, the dust-containing airflow 9 proceeds downward and enters the optical pickup section 5 through the opening window 7, and may adhere to internal optical components, light-receiving sensors, and the like to be contaminated. . From such a thing,
Correct input and output of optical signals will not be obtained, accurate recording,
Playback will stop.

[0005]

According to a first aspect of the present invention, a laser beam emitted from a laser light source is focused on a recording surface of a disc-shaped information recording medium so as to condense a light spot. Objective lens driving mechanism for driving the objective lens in a direction parallel to and perpendicular to the recording surface of the information recording medium, and an optical pickup covering the objective lens driving mechanism and the objective lens. In an objective lens driving device having a protective cover whose one end is fixed to a portion, an outer wall of the protective cover which has an outlet on an inner wall side of the protective cover near the lens surface of the objective lens and communicates with the outlet. A cavity for blowing air having an inlet on the side was formed.

According to a second aspect of the present invention, in the first aspect of the invention, the cavity cross-sectional area of the discharge port on the side of the cavity portion of the protective cover closer to the objective lens is set to the cavity cross-sectional area of the other region including the suction port. Formed smaller than.

According to a third aspect of the invention, in the first aspect of the invention, the hollow cross-sectional area of the hollow portion of the protective cover is continuously reduced from the inlet side toward the outlet side.

[0008]

According to the first aspect of the present invention, the protective cover is provided with the cavity communicating from the outer suction port side to the inner discharge port side, so that the drive device holding the objective lens is located at the target position of the information recording medium. When moving, air can be discharged from the exhaust port arranged on the objective lens side through the suction port of the cavity, so dust and the like adhering to the lens surface can be blown off, and thus the surface of the objective lens can be constantly maintained. It is possible to keep it in a clean state. Moreover, the direction of the flow of the air flowing out from the outlet is the direction that blocks the flow of the air that enters the protective cover from the information recording medium side (actually, the direction is orthogonal, but here it does not enter the inside). It means that the optical parts and the like in the optical pickup section are not contaminated.

According to the second aspect of the present invention, by making the cavity cross-sectional area on the outlet side small and making it into a nozzle shape, it is possible to increase the outflow velocity of air near the outlet, whereby the surface of the objective lens is It is possible to further enhance the effect of blowing off the accumulated dust and the like.

According to the third aspect of the present invention, the cavity cross-sectional area is continuously and gradually reduced from the inlet side to the outlet side to suppress the pressure loss of the air flow, and thereby the air flowing out. Since the outflow rate can be increased without decreasing the flow rate of, the effect of blowing off the dust accumulated on the surface of the objective lens can be further enhanced.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the invention described in claim 1 will be described with reference to FIG. The objective lens 10 is an objective lens holder 11
Have been held in. A coil 12 is wound around the side surface of the objective lens holder 11. A magnet 13 having a U-shape facing upward so as to sandwich the coil 12.
Is provided. The objective lens holder 11, the coil 12, and the magnet 13 form an objective lens driving mechanism 14. The objective lens holder 11 is
By changing the current passed through the coil 12, the coil 12 can be moved in the vertical direction (X-axis direction) and the rotation direction (circumferential direction of the side surface of the objective lens holder 11 around the axis 15). Thus, the objective lens 10 can be focused on the target position of the optical disc 16 as the information recording medium. A protective cover 17 is provided so as to cover the entire objective lens driving mechanism 14. The protective cover 17 is provided with an opening 18 on an extension line above the optical axis of the objective lens 10. Further, an optical pickup unit 20 is arranged below the optical axis of the objective lens 10. This optical pickup unit 2
Inside 0, a laser light source (not shown) for recording information on the optical disc 16, an optical system associated with the laser light source, a signal detector, etc. are provided.

In the objective lens driving device as described above, in this embodiment, a cavity 19 for blowing air is newly formed on the side wall of the protective cover 17. This cavity 19
Has an outlet 19a on the inner wall side close to the lens surface of the objective lens 10 and an inlet 19b on the outer wall side communicating with the outlet 19a.

In such a structure, the optical disk 16
The dust (not shown) inside the device that has been wound up due to the rotation of the optical pickup 20 and the movement of the optical pickup portion 20 spontaneously falls with the passage of time and accumulates on the lens surface of the objective lens 10 through the opening 18 of the protective cover 17. When the optical pickup unit 20 is moved in the radial direction (Y-axis direction) of the optical disc 16 in order to read the information of the target track position on the recording surface in the state where the dust is accumulated on the lens surface, Air flows in from the suction port 19b side of the cavity portion 18, and the inflowing air passes through the inside of the cavity and is discharged from the discharge port 19a side arranged on the lens surface of the objective lens 10 as shown by the arrow. Objective lens 10
The dust accumulated on the lens surface can be blown away. At the same time, the direction of the air flow discharged from the discharge port 19a is a direction that blocks the direction in which dust enters from above the opening 18, and the objective lens holder 11 and the magnet 13 are optical pickups. The structure is such that dust does not easily enter the portion 20.

Therefore, from the above, the surface of the objective lens can be always kept clean, and
Since it is possible to prevent dust from entering the optical pickup section 20, recording and reproduction with a laser beam can be accurately performed.

Next, an embodiment of the invention described in claim 2 will be described with reference to FIG. The description of the same parts as those of the invention according to claim 1 (see FIG. 1) is omitted, and the same reference numerals are used for the same parts.

Here, the nozzle 19 is formed so that the hollow cross-sectional area of the discharge port 19a of the hollow portion 19 of the protective cover 17 is smaller than the hollow cross-sectional area of the other region including the suction port 19b. With such a nozzle shape, the air that has flowed in through the suction port 19b of the cavity 19 enters the nozzle-shaped discharge port 19a, whereby the velocity is further accelerated inside the discharge port 19a, and in the vicinity of the lens of the discharge port 19a. Will be discharged at a further increased speed. Therefore, since the effect of blowing off the dust accumulated on the surface of the objective lens can be further improved as compared with the configuration of FIG. 1, the lens surface can be kept in a cleaner state. Recording and reproduction by can be performed more accurately.

Next, an embodiment of the invention described in claim 3 will be described with reference to FIG. The description of the same parts as those in the first aspect of the present invention will be omitted, and the same reference numerals will be used for the same parts.

Here, the cavity section 19 of the protective cover 17 is formed so that the cavity cross-sectional area thereof continuously decreases gradually from the suction port 19b side toward the discharge port 19a side. By making the shape such that it becomes smaller continuously, it is possible to suppress the pressure loss of the air flow as compared with the case of the nozzle shape as described above, and as a result, the flow rate of the air flowing out from the cavity portion 19 is reduced. It can be an increase in speed without a decrease. Therefore, from the above, the effect of blowing off the dust accumulated on the lens surface can be further improved, and the effect of cleaning the lens surface can be further improved.
The reproduction can be made more accurate.

[0019]

According to the first aspect of the present invention, an objective which is arranged to face a disc-shaped information recording medium and focuses a laser beam emitted from a laser light source onto a recording surface of the information recording medium to irradiate a light spot. A lens, an objective lens drive mechanism for driving the objective lens in a direction parallel to and perpendicular to the recording surface of the information recording medium, and an objective lens drive mechanism for covering the objective lens and the objective lens, In an objective lens driving device having a fixed protective cover, an outlet is provided on an inner wall side of the protective cover near the lens surface of the objective lens, and an inlet is provided on an outer wall side of the protective cover communicating with the outlet. Since the cavity for blowing air is formed, the objective lens is passed through the suction port of the cavity when the drive device holding the objective lens moves to the target position of the information recording medium. It is possible to blow out air from the exhaust port located at the position to blow away dust and the like adhering to the lens surface, which keeps the surface of the objective lens clean at all times, so recording and reproduction with a laser beam can be performed accurately. Is something that can be done. In addition, the direction of the flow of air flowing out from the outlet is the direction that blocks the flow of air that enters the protective cover from the information recording medium side (actually, it is a direction that is orthogonal, but here it does not enter the inside). Therefore, it is possible to prevent the optical parts and the like in the optical pickup section from being contaminated, and the signal reproduction and the like can be accurately performed.

According to a second aspect of the invention, in the first aspect of the invention, the cavity cross-sectional area of the discharge port on the side closer to the objective lens of the cavity portion of the protective cover is set to the cavity cross-sectional area of the other region including the suction port. Since it is formed smaller than this, by making the discharge port a nozzle shape in this way, it is possible to increase the outflow velocity of air near the discharge port, and this has the effect of blowing away dust and the like accumulated on the surface of the objective lens. Since it can be further increased, recording with a laser beam,
The reproduction can be performed more accurately.

According to a third aspect of the present invention, in the first aspect of the present invention, the hollow cross-sectional area of the hollow portion of the protective cover is continuously reduced from the inlet side toward the outlet side. By continuously changing the shape from the inlet side to the outlet side, it is possible to suppress the pressure loss of the air flow and increase the outflow speed without reducing the flow rate of the outflowing air. As a result, the effect of blowing off the dust accumulated on the surface of the objective lens can be further enhanced, so that recording and reproduction by the laser beam can be performed more accurately.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a configuration of an objective lens driving device that is an embodiment of the invention described in claim 1.

FIG. 2 is a cross-sectional view showing a configuration of an objective lens driving device that is an embodiment of the invention described in claim 2.

FIG. 3 is a cross-sectional view showing the configuration of an objective lens driving device that is an embodiment of the invention as set forth in claim 3.

FIG. 4 is a cross-sectional view showing a configuration of a conventional objective lens driving device.

[Explanation of symbols]

 10 Objective Lens 14 Objective Lens Driving Mechanism 17 Protective Cover 16 Information Recording Medium 19 Cavity 19a Discharge Port 19b Suction Port 20 Optical Pickup Section

Claims (3)

[Claims] 1. An objective lens, which is arranged so as to face a disc-shaped information recording medium and condenses a laser beam emitted from a laser light source onto a recording surface of the information recording medium to irradiate a light spot, and the objective lens. The information recording medium includes an objective lens driving mechanism that drives in a direction parallel to and a direction perpendicular to the recording surface of the information recording medium, and a protective cover that covers the objective lens and the objective lens and has one end fixed to an optical pickup unit. In the objective lens driving device described above, a blower cavity having an outlet on the inner wall side of the protective cover near the lens surface of the objective lens and an inlet on the outer wall side of the protective cover communicating with the outlet is provided. An objective lens driving device characterized by being formed. 2. The hollow cross-sectional area of the discharge port on the side of the hollow portion of the protective cover closer to the objective lens is smaller than the hollow cross-sectional area of the other region including the suction port. Objective lens driving device. 3. The objective lens driving device according to claim 1, wherein the hollow cross-sectional area of the hollow portion of the protective cover is continuously reduced from the inlet side toward the outlet side.