JPH0369027A - Optical pickup device - Google Patents

Abstract

PURPOSE:To prevent the contamination of an optical system by forming the housing of an objective lens moving mechanism into a hermetic structure with respect to the outside and supplying clean air to the housing of the optical system and the housing of the objective lens moving mechanism. CONSTITUTION:The mounting parts of a laser diode 1 and a split ring lens 2, the mounting parts of photodetectors 9, 10 and the connecting parts of the housings 11, 12 are made into the hermetic structure with respect to the outside. The outdoor air subjected to dust removal through an air filter 14 is withdrawn into an air pump 13 and is fed into the inside of the housing 11 when the driving of the optical disk device is started and an air pump 13 is operated by the above-mentioned constitution. The inside of the housings 11, 12 attains a positive pressure state with respect to the outdoor air. The outdoor air withdrawn by the operation of the fan for air cooling is, therefore, prevented from infiltering the inside of the housings 11, 12. The clean air fed into the housings 11, 12 is blown through the inside of the objective lens mechanism and around the objective lens 5 to the surface of the disk 6.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an optical pickup device for storing/reproducing data on an optical storage medium.

[Prior Art] An optical disk device that uses an optical disk as a storage medium includes a rotational movement system for the optical disk, a seek system for seeking an optical pickup device for recording/reproducing data on the optical disk, and a light source generated by the optical pickup device. It houses various motion sources such as a semiconductor laser element and an objective lens moving mechanism that moves the objective lens for imaging the laser beam onto an optical disk. Heat is generated from the drive circuit that operates the power source, and the temperature inside the casing of the optical disk device can rise to several tens of degrees.

In this way, when the temperature inside the device increases, it causes problems such as deterioration of the optical disk and accelerated deterioration of the semiconductor laser element. is forced to cool.

In addition, when outside air is sucked into the casing for cooling, the dust contained in the outside air is also drawn into the casing, and the inside of the apparatus is contaminated by the drawn dust.

Therefore, a dust filter for air purification is attached to the air intake port to remove dust from the outside air that is taken in.

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

In other words, there are gaps in the housing in addition to the air intake, and outside air flows in through these gaps, and the dust contained in the outside air enters the inside of the optical pickup device and contaminates the optical system. It was causing inconvenience.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an optical pickup device that can prevent the optical system from becoming dirty.

[Means for Solving the Problems] The present invention provides an optical system housing of an optical pickup device, and
The objective lens moving mechanism housing has a sealed structure from the outside. Further, clean air is supplied to the optical system housing and the objective lens moving mechanism housing.

[Function] Therefore, dust is prevented from entering the inside of the optical pickup device, so dirt does not adhere to the optical system, etc., and the supplied clean air keeps the inside of the housing symmetrical with respect to the outside. This prevents dust from entering the housing from the outside, and clean air blows out from around the objective lens and onto the surface of the optical disk, creating an air curtain in this area. .

Dust is prevented from adhering to the surface of the optical disk.

[Embodiments] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIGS. 1(a) and 2(b) and 2 show an optical pickup device according to an embodiment of the present invention. This optical pickup device uses the Knifezi method to detect the focus error of the laser beam, and the push-pull method to detect the positioning error of the laser beam to the recording track. is moved in the radial direction of the optical disc.

In the figure, a laser diode (semiconductor laser element) l
The laser beam output from is converted into parallel light (hereinafter referred to as laser beam) by the coupling lens 2,
After passing through the polarizing beam splitter 3 and being converted into circularly polarized light by the 174-wave plate 4, the light is focused by the objective lens 5 and focused onto the recording track of the optical disk 6.

This reflected light from the optical disk 6 (hereinafter referred to as signal light)
is converted into substantially parallel light through the objective lens 5, and then passes through the 174-wave plate 4 again, where it is converted into linearly polarized light whose polarization axis is perpendicular to the laser beam output from the laser diode l. By.

It is reflected by the polarizing beam splitter 3 in the direction of the lens 7.

Approximately half of the light flux that has passed through the lens 7 is reflected by the knife division #I8, and as shown in FIG. The light is incident on the divided light receiving element 9 for track servo, and the other part is imaged on the light receiving element 10 for focus servo, whose light receiving surface is divided into two by a dividing line parallel to the ridge line 8a of the split mirror 8. be done.

The objective lens 5 is also provided with a tracking mechanism for positioning the objective lens 5 in the radial direction of the optical disk 6, and a focusing mechanism for focusing. Note that, hereinafter, the tracking mechanism and the focusing mechanism are collectively referred to as an objective lens moving mechanism 5a.

Then, a tracking error signal is formed based on the light reception signal of the light receiving element 9, and a focusing error signal is formed based on the light reception signal of the light receiving element 10, and these error signals are transmitted to the tracking servo system and the focusing Each is fed back to the servo system.

The objective lens moving mechanism 5a is controlled by these servo systems, and the focal point 5 of the objective lens is positioned on the surface of the optical disk 6, and is focused by the objective lens 5 and formed on the surface of the optical disk 6. A spot is positioned on the recording track.

Further, a reproduction signal is formed based on the sum of the light reception signal of the light receiving element 9 and the light reception signal of the light receiving element 10, and processing for data recording/reproduction is performed based on the reproduction signal.

In addition, while forming a laser beam, the objective lens 5
Optical system housing 1 for processing the signal light returned from
1 has a sealed structure, and the housing 12, which is connected to the housing 11 and houses the objective lens moving mechanism 5a, has a portion excluding the space necessary for moving the objective lens 5. is constructed in a sealed structure.

Note that the optical axis of the objective lens 5, which is aligned in one direction perpendicular to the surface of the optical disk 6, is made to coincide with the optical axis of the laser diode l, which is aligned in a direction parallel to the surface of the optical disk 6. Therefore, at the connecting part between the housing 11 and the housing I2,
An optical axis deflecting element (not shown) such as a prism is provided.

Furthermore, an air filter 14 is attached to the air intake port of the air pump 13 to remove dust contained in the outside air, and the air supplied from the air pump 13 is sent to the housing 11 through an air tube 15. ing.

Further, the light receiving elements 9 and 10 are fixed to the holder 17 with an adhesive 16, for example, as shown in FIG. 3(a),
By fixing this holder 17 to the housing 11, the light receiving element 10(9) is attached to the housing 111. At times, the fixing position of the light receiving element 10 (9) is adjusted so that the light receiving element 10 (9) is installed at a prescribed position.

Here, the mounting surfaces of the holder 17 and the casing 11 are machined into highly accurate flat surfaces, and therefore no gaps are formed in the mounting portions of the casing 11 and the light receiving elements 9 and 10.

In addition, the laser diode l and the coupling lens 2
are combined to form a unit 18, and the portion where this unit 18 is attached to the housing 1 is also formed into a sealed structure.

Further, sealing members 19 and 20 are provided at the connecting portion between the casings 11 and 12 to maintain airtightness of this portion.

In this way, the laser diode 1 and the installment ring lens 2 are attached partially, the light receiving elements 9 and 10 are attached partially, and the connection between the casing 11 and the casing 12 is sealed to the outside. Therefore, the inside of the housing 11 has a completely sealed structure from the outside.

With the above configuration, when the optical disk device (not shown) starts opening and the cooling fan (not shown) starts operating,
Air pump 13 is activated.

As a result, the outside air from which dust has been removed through the air filter 14 is drawn into the air pump 13 and sent into the housing 11 through the air tube 15, and the inside of the housing 11.12 is brought into a positive pressure state relative to the outside air. The outside air drawn in by the operation of the cooling fan is prevented from entering the housing 11, 12.

In addition, when the optical disk 6 is attached to the optical disk device and data access is made to the optical disk 6, the air pump 1
The clean air sent into the housing 11.12 from 3 passes through the inside of the objective lens moving mechanism 5a and around the objective lens 5, blows out from the opening 12a of the housing 12, and is blown onto the surface of the optical disk 6. It will be done.

As a result, an air curtain is formed between the objective lens 5 and the surface of the optical disk 6, so that dust is prevented from adhering to the surface of the optical disk 6.

In this way, in this embodiment, since the outside air is prevented from entering into the inside of the housing 11.12, it is possible to prevent dust from adhering to the optical components.
It is also possible to prevent dust from adhering to the surface of the optical disk 6.

Furthermore, since the casing 11.12 has a sealed structure, the air supply capacity of the air pump 13 that sends clean air into the casing 11.12 may be small, which increases the cost when adding this dustproof mechanism. can be suppressed.

FIGS. 3(b) and 3(C) show other examples of structures in which the light receiving elements 9 and 10 are attached to the housing 11, respectively.

In the case shown in FIG. 6(b), a circle ring 21 is disposed between the housing 11 and the holder 17, and this attachment improves the degree of sealing of the part.

In addition, in the case shown in FIG.
By sealing the area around the contact portion between 1 and the holder 17.

This installation improves the airtightness of the area.

Incidentally, in the embodiments described above, the present invention is applied to an optical pickup device that records/reproduces data on an optical disk, but it is also applicable to an optical pickup device that records/reproduces data on a magneto-optical disk.

The invention can be applied in a similar manner.

In addition, in the above-described embodiment, a sealing member is provided at the connecting portion between the optical system housing and the objective lens moving mechanism housing to maintain the airtightness of this connecting portion. The configuration for holding is not limited to this.

In addition, in the above-mentioned embodiment, by the Naifetsu method,
The present invention is applied to an optical pickup device that detects a focus error of a laser beam and also detects a positioning error of the laser beam to a recording track by a push-pull method, but the present invention is not applicable to devices equipped with other error detection mechanisms. The present invention can also be applied in the same manner.

[Effects of the Invention] As explained above, according to the present invention, since the optical system housing and the objective lens moving mechanism housing have a sealed structure from the outside, dust cannot enter into the inside of the housing. This prevents dirt from adhering to the optical system, etc.
Since clean air is supplied to the optical system housing and the objective lens moving mechanism housing, the supplied clean air creates a positive pressure inside the housing relative to the outside. This prevents dust and other particles from entering.

Further, since clean air is blown out from around the objective lens and blown onto the surface of the optical disk, an air curtain is formed in this area, so that the effect of preventing dust from adhering to the surface of the optical disk is obtained.

[Brief explanation of drawings]

FIGS. 1(a) and (b) are schematic diagrams showing the configuration of an optical system of an optical pickup device according to an embodiment of the present invention, and FIG. FIG. 3(a) is a schematic partial sectional view showing an example of the structure in which the light-receiving element is attached; FIG. 3(b) is a schematic perspective view showing an example of the structure in which the light-receiving element is attached. Schematic partial cross-sectional view, FIG. 3(C) is a schematic partial cross-sectional view showing an example of a structure in which a light-receiving element is attached. 5... Objective lens, 5a... Objective lens moving mechanism, 11.12... Housing, 12a... Opening, 13...
...Air pump, 14...Air filter, 15...
Air tube, 16...Adhesive, 17...Holder,
19.20... Seal member, 21... O-ring. ■1 Figure 5 8 (a) Figure 3 (b) (C)

Claims (2)

[Claims] (1) An optical pickup device for storing/reproducing data on an optical storage medium, which houses a light source and an optical system for optically processing the reflected light from the optical storage medium, and is configured in a sealed structure from the outside. It houses an optical system housing and an objective lens moving mechanism that moves an objective lens for focusing a laser beam on an optical storage medium and returning reflected light from the optical storage medium to the optical system, and has a nearly sealed structure from the outside. 1. An optical pickup device comprising an objective lens moving mechanism housing configured as shown in FIG. (2) An optical pickup device for storing/reproducing data on an optical storage medium, which houses an optical system for optically processing the light source light and the reflected light from the optical storage medium, and is configured in a sealed structure from the outside. The structure is almost sealed from the outside, housing the optical system housing and the objective lens moving mechanism that moves the objective lens for focusing the laser beam on the optical storage medium and returning the reflected light from the optical storage medium to the optical system. What is claimed is: 1. An optical pickup device comprising: an objective lens moving mechanism housing configured as described above; and an air supply means for supplying clean air to the optical system housing and the objective lens moving mechanism housing.