JPH03212827A - Optical pickup - Google Patents

Abstract

PURPOSE:To prevent the resitcking of dust by providing a conductive coating layer on the surface of a glass objective lens. CONSTITUTION:The light beam emitted from a light source is projected via the glass objective lens 1 on a recording medium 2 to execute reading/writing of data on the recording medium 2. The conductive coating layer 3 is provided on the surface of the glass objective lens 1. The conductive coating layer 3 provided on the surface of the glass objective lens 1 prevents the electrification of the glass objective lens 1. The resticking of the dust is prevented in this way.

Description

[Detailed Description of the Invention] [Summary] An optical pickup that projects a light beam emitted from a light source onto a recording medium through a glass objective lens and reads/writes data to the recording medium. The object of the present invention is to provide an optical pickup that can prevent dust from re-adhering, and is configured such that a conductive coating layer is provided on the surface of the glass objective lens.

[Industrial Application Field] The present invention relates to an optical pickup that projects a light beam emitted from a light source onto a recording medium through a glass objective lens, and reads/writes data to/from the recording medium. .

In recent years, due to the diversification of installation locations due to the expansion of the range of use of OA equipment, various optical disks are being used in harsh environments not seen in conventional computer environments. Therefore, dust may adhere to the optical system of the optical disk or the recording medium, causing various problems in data reading/writing and various servos. Therefore, there is a demand for an optical pickup that is less prone to troubles caused by such dust and the like.

[Prior Art] Conventionally, in an optical disk device, dust adhering to an objective lens is periodically wiped off with a soft cloth or the like.

Further, a cleaning device in which a brush mechanism is disposed inside the case of the recording medium cartridge is also used. This cleaning device is set in an optical disk device and cleans the surface of an objective lens by driving a brush mechanism.

[Problems to be Solved by the Invention] However, as described above, when wiping off dust etc. attached to the objective lens with a cloth or cleaning the surface of the objective lens using a cleaning device, it is difficult to clean the surface of the objective lens. Because of the rubbing, static electricity accumulates on the objective lens, and there is a problem in that dust and the like are likely to re-adhere.

In particular, in the case of glass lenses, since they are coated only with anti-reflection coating, there is a problem in that they are greatly affected by charging.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an optical pickup that can prevent dust from re-adhering.

[Means for Solving the Problems] FIG. 1 is a diagram showing the principle of the optical pickup of the present invention. In the figure, reference numeral 1 indicates a light beam emitted from a light source to a recording medium 2.
This is a glass objective lens that projects onto the object.

A conductive coating layer 3 is provided on the surface of the glass objective lens 1.

[Function] In the optical pickup shown in FIG. 1, the conductive coating rfk3 provided on the surface of the glass objective lens 1
prevents the objective lens 1 from being charged.

[Example] Next, an example of the present invention will be described with reference to the drawings. Second
The figure is a configuration diagram showing an embodiment of the present invention. Figure 3 is a cross-sectional configuration diagram of the objective lens portion in Figure 3. Figure 3 is a configuration diagram showing an embodiment of the invention. Figure 4 is shown in Figure 3. FIG. 2 is an explanatory diagram of an optical system of an optical pickup.

First, the overall configuration of the optical pickup of this embodiment will be explained using FIG. In this figure, reference numeral 11 denotes a base that is movable in the track direction of the disk while being guided by a guide shaft (not shown).

A laser diode 12 is provided on the side of the base 11 and emits a laser beam. 13 is a half mirror that reflects 50% of the laser beam from the laser diode 12 and transmits 50% of it.

14 is a collimator lens that converts the diverging beam from the laser diode 12 into a parallel beam.

Reference numeral 15 denotes a mirror that changes the traveling direction of the parallel beam from the collimator lens 14 upward. Reference numeral 16 denotes an objective lens that focuses a parallel beam whose traveling direction has been changed by a mirror onto a disk 20 (recording medium) not shown.

17 is a condenser lens that condenses the reflected light from the disk 20 that has passed through the half mirror 13, and 18 is a photodiode on which the beam condensed by the condenser lens 17 hits.

Next, the objective lens 16 will be explained using FIG.

In this figure, 21 is a lens holder that holds a plurality of lenses. A conductive coating layer is formed on the disc-facing surface of the glass lens 22 that faces the disc 20 among the plurality of lenses. In this embodiment, a nine oxide film (S i 02 ) is formed by sputtering.

Next, the operation of the above configuration will be explained using FIG. 4. First, the case of information reproduction will be explained. The laser beam emitted from the laser diode 12 first passes through a half mirror.
The laser beam is separated into two directions by 13, and the reflected laser beam enters a collimator lens 14. The collimator lens 14 converts the laser beam into a parallel beam, which enters the objective lens 16 . Then the laser beam is focused,
The light is focused onto the disk 20.

The laser beam reflected by the disk 20 is again reflected by the objective lens 16. Through the collimator lens 14, the half mirror
It reaches 13. Here, the laser beam is separated into two directions, and the transmitted laser beam is focused by a condensing lens 17.
The light is focused onto the photodiode 18. Here, an information reproduction signal, a tracking error signal, and a focusing error signal are detected.

Next, a case in which information is written to the disc 20 will be described. The laser beam 12 emits a laser beam on which written information is superimposed. This laser beam reaches the disk 20 through the same path as when reading information. Here, information is written to the disk 20.

According to the above configuration, the glass lens 22 facing the disk 20 of the objective lens 16 has a conductive coating layer 2.
3 is formed. Therefore, the glass lens 22 can be removed using cloth or the like.
Even if the surface of the glass lens 22 is rubbed when wiping off dust etc. attached to the glass lens 22 or cleaning the surface of the glass lens 22 using a cleaning device, static electricity will not be accumulated on the glass lens 22 and the dust etc. will be removed. It becomes difficult to reattach.

[Effects of the Invention] As explained above, according to the present invention, by providing a conductive coating layer on the surface of the glass objective lens, it is possible to realize an optical pickup that can prevent dust from re-adhering. .

[Brief explanation of drawings]

Figure 1 is a diagram showing the principle of the present invention. Figure 2 is a block diagram showing an embodiment of the present invention. Figure 3 is a cross-sectional diagram of the objective lens portion in Figure 3. Figure 3 is a diagram showing an embodiment of the present invention. The configuration diagram, FIG. 4, is an explanatory diagram of the optical system of the optical pickup shown in FIG. 3. 1 to 4, 1.22 is a glass objective lens, 2.20 is a recording medium, and 3.23 is a conductive coating layer.

Claims (1)

[Claims] The light beam emitted from the light source is transmitted through a glass objective lens (1
) to the recording medium (2), and the recording medium (
In contrast to 2), an optical pickup for reading/writing data, characterized in that a conductive coating layer (3) is provided on the surface of the glass objective lens (1).