Disc cartridge

A disc cartridge includes a shutter unit having an outer shutter and inner shutters to open and shut apertures on the disc cartridge. The outer shutter opens one of the inner shutters corresponding to a side of the disc cartridge being accessed by a pickup. Accordingly, the overall area of the apertures exposed to the exterior during information recording and reproducing operations is reduced. Accordingly, dust is less likely to enter into the disc cartridge.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Korean Patent Application No. 2001-35759 filed on Jun. 22, 2001, in the Korean Industrial Property Office, the disclosure of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a disc cartridge for receiving an information recording/reproducing medium, such as a disc, and more particularly, to a disc cartridge which prevents dust from entering into the disc cartridge.

2. Description of the Related Art

FIGS. 1 and 2show a conventional disc cartridge10for receiving a disc D to be used in an information reproducing apparatus100. The disc cartridge10includes upper and lower cases11and12which form an internal space to receive the disc D, a holder13which is inserted into and combined with the upper and lower cases11and12while holding the disc D, and a shutter14which selectively opens and shuts apertures11aand12a, which are formed on the upper and lower cases11and12of the disc cartridge10. The apertures11aand12aallow a pickup130of the information recording apparatus100to access the disc D.

Receiving openings11band12bare formed to be connected with the apertures11aand12a, so as to allow a clamping domain D1of the disc D to be clamped by a turntable110and a damper120of the information recording apparatus100. The receiving openings11band12b, similarly to the apertures11aand12a, are open or shut through opening or shutting of the shutter14.

FIGS. 3A and 3Bshow an opening operation of the shutter14of the disc cartridge10. The reference numeral150denotes an opening lever installed in a cover101of the information recording apparatus100, which opens and shuts the shutter14. As shown inFIGS. 3A and 3B, with reference toFIG. 1, where the disc cartridge10is inserted into the information recording apparatus100, one end of the opening lever150is locked into a locking sill14aof the shutter14. As the lever150is rotated, the shutter14is thereby opened. A spring151provides a return force to return the opening lever150to an original position as the disc cartridge10is ejected from the information recording apparatus100.

Since the disc D can be single-sided or double-sided, the upper and lower cases11and12of the disc cartridge10are formed symmetrical to each other, and allow both sides of the disc D to be used. In other words, with reference toFIG. 2, the apertures11aand12aand the receiving openings11band12bare identical and are formed symmetrically on the upper and lower cases11and12, so as to allow the pickup130to access one side of the disc D or the other side of the disc D in response to turning of the disc cartridge10upside down/right side up.

The main reason why the disc D is used while being encased in the disc cartridge10is to protect it from alien substances such as dust. That is, an alien substance such as dust can attach itself to a surface of the disc D and obstruct an accurate signal processing operation during information recording and reproducing operations. This problem is compounded especially in the case of a high-density disc. However, it is inevitable that dust enters the disc cartridge10, through the upper and lower apertures11aand12a, because the shutter14must be opened to allow the pickup130to access the disc D during the information recording or reproducing operations. With the conventional disc cartridge10, an aperture of the unused side of the disc D,11a/12awhich is not being accessed by the pickup130, is, nevertheless, completely opened by the opening of the shutter14. Therefore, the conventional disc cartridge10allows a lot of dust to build up in the apertures11aand12a. Accordingly, measures to prevent such a problem are needed.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to provide an improved disc cartridge which prevents dust from entering into the disc cartridge.

To achieve the above and other objects of the present invention, there is provided a disc cartridge for receiving a disc, comprising a case which receives the disc and a shutter unit which selectively opens and closes apertures formed on the case according to sliding directions of the shutter unit, wherein the shutter unit comprises a double-layer structure of inner shutters and an outer shutter.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIGS. 4 through 7show a disc cartridge20according to an embodiment of the present invention. Referring toFIG. 4, the disc cartridge20includes upper and lower cases21and22which form an internal space to receive a disc D, and a shutter unit including shutters24,25, and26which selectively open and shut apertures21aand22aand receiving openings21band22bformed on the corresponding upper and lower cases21and22.

The shutter unit has a double-layer structure of an outer shutter24and inner shutters25and26. In other words, the inner shutters25and26cover the apertures21aand22aformed on corresponding sides of the disc cartridge20, and the outer shutter24is arranged over the inner shutters25and26, and covers the apertures21aand22aand the receiving openings21band22b.

The inner shutters25and26are connected to the outer shutter24by an interlock to be alternately opened with the outer shutter24according to sliding directions of the outer shutter24. The interlock includes torsion springs27which provide an elastic force to the inner shutters25and26in directions to cover the apertures21aand22aand the receiving openings21band22b, a locking projection24aformed on the outer shutter24, and interference projections25aand26aformed on the inner shutters25and26.

The locking projection24ais formed on a central portion of an inner wall of the outer shutter24, and the interference projections25aand26aof the inner shutters25and26are located at both sides of the locking projection24ato face each other. Accordingly, as the outer shutter24slides in a right direction ofFIG. 4, the locking projection24apushes the interference projection25aof the inner shutter25to open the inner shutter25.

As shown inFIG. 5, where the outer shutter24slides in the opposite direction, the interference projection26aof the inner shutter26is pushed to open the inner shutter26. In other words, only one of the inner shutters25and26is selectively opened while the other inner shutter25or26is maintained in a shut state according to the sliding directions of the outer shutter24.

Referring back toFIG. 4, sliding guide projections25band26bare formed on the corresponding interference projections25aand26ato be inserted into slots23on the disc cartridge20along sliding directions of the inner shutters25and26.

FIG. 5shows that where the disc cartridge20is mounted on a tray140of FIG.1and inserted into an information recording apparatus100ofFIG. 1, one end of an opening lever150is locked into a locking sill24bof the outer shutter24. As the lever150is rotated, the outer shutter24is thereby opened. In this case, the locking projection24aof the outer shutter24pushes the interference projection26aof the inner shutter26to simultaneously open the inner shutter26. As a result, the aperture22aon the lower case22is opened, as shown inFIG. 6A, and a pickup130ofFIG. 1can access one side of the disk D through the open aperture22a. In contrast, the aperture21aon the upper case21is shut by the inner shutter25, as shown in FIG.6B. That is, while the aperture22ais open to allow the one side of the disc D to be used and accessed by the pickup130ofFIG. 1, the opposite side of the disc D is sealed up, except for the receiving opening21b.

However, the receiving opening21bis not completely open because it is combined with a damper120ofFIG. 1, which is almost the same size as the receiving opening21b, according to the clamping of the disc D.

Therefore, where information is recorded on or reproduced from the disc D under the above-mentioned condition, dust that otherwise enters freely through the unused side of the disc D can be suppressed to a great extent. Compared to a conventional disc cartridge, the overall area of apertures of a disc cartridge of the present invention, which is open to the exterior during the information recording and reproducing operations, can be reduced by almost half. Accordingly, dust is less likely to enter into the disc cartridge20of the present invention, and errors can be prevented during a signal processing operation.

Where the disc cartridge20is ejected from the information recording apparatus100ofFIG. 1, the opening lever150is returned to an original position, and the inner shutter26and the outer shutter24are returned to their original positions by the torsion spring27to shut the aperture22a.

To use the other side of the disc D, the disc cartridge20is first pulled out from the information recording apparatus100ofFIG. 1, turned upside down, and inserted back into the information recording apparatus100ofFIG. 1with the inner shutter25facing downward. Accordingly,FIG. 7shows that the outer shutter24is opened with the inner shutter25by the opening lever150. In other words, although the opening lever150, for example, always opens the outer shutter24in one direction, the other inner shutter25is open, because the disc cartridge20is turned upside down. Here, the other side of the disc D is accessed by the pickup130ofFIG. 1via the aperture21a. As in the above, the unused side of the disc D, which is not accessed by the pickup130, is sealed up by the inner shutter26. Therefore, the dust that otherwise enters without restrictions through the unused side of the disc D can be suppressed.

With the present invention, both sides of the disc D can be used. However, dust can be prevented from entering through an aperture on the unused side of the disc D.

A disc cartridge according to the present invention selectively and individually opens and shuts apertures formed on the disc cartridge. The disc cartridge includes a shutter unit having a double-layer structure of an outer shutter and inner shutters. The outer shutter opens one of the inner shutters corresponding to a side of a disc being accessed. Thus, as compared to a conventional disc cartridge, the area of the apertures of the disc cartridge of the present invention, which is exposed to the exterior during information recording and reproducing operations, can be reduced by almost half. Accordingly, dust is less likely to enter into the disc cartridge.