1. Field of the Invention
The present invention relates to a disc cartridge which rotatably accommodates a disc-shaped disc medium used as a recording/playback medium of an information processing device or the like, and which prevents entry of dust or the like.
2. Description of the Related Art
A disc-shaped disc medium, such as an optical disc, a magneto-optical disc, or the like, is used, for example, as a portable recording/playback medium for a computer. When recording or playback of the disc medium is carried out, laser beam is illuminated onto the recording surface while the disc medium is rotated in a state of being loaded in a drive device. In this way, recording of information is carried out by pit formation or phase changes or magnetization or the like due to decomposition of the dye layers of the recording surface, or recorded information is played back on the basis of differences in the reflectivity or the polarizing angle of the laser beam.
Further, in such disc media, shortening of the wavelength of the laser beam which is illuminated onto the recording surface has been proposed in order to increase the recording capacity. When recording or playback of information is carried out by using this short-wavelength laser beam (e.g., a blue-violet color laser), in order to suppress the attenuation of the laser beam due to the cover layer which protects the recording surface of the disc medium, the cover layer must be made thin. By making the cover layer thin in this way, the diameter of the laser beam at the surface of the cover layer (the surface which is exposed to the exterior) decreases, and it is not possible to ignore the effects of dust and the like adhering to the surface of the cover layer.
Thus, disc cartridges, which accommodate a disc medium in a case and prevent adhesion of dust or the like onto the disc medium, are employed. Such a disc cartridge is formed to include an opening, which is for exposing to the exterior a center hole portion (center core portion) provided at the central portion of the disc medium and a portion of the recording surface (the cover layer), and a shutter member which opens and closes this opening.
In this way, in the disc cartridge, generally, by closing the opening by the shutter member, entry of dust or the like into the disc cartridge, i.e., adhesion of dust or the like onto the disc medium, is prevented, and by opening the opening as the disc cartridge is loaded into the drive device, the center hole portion (the center core portion) can be held by a rotation spindle shaft, and the laser head can approach the recording surface (laser beam can be illuminated).
Further, in such a disc cartridge, in the aforementioned state in which the opening is open, there is the need to ensure a space for accommodating the shutter member. Also, it is desired to make the disc cartridge compact and thinner. Thus, to aim for compactness and thinness, a disc cartridge in which the shutter member is divided in two has been disclosed in Japanese Patent Application Laid-Open (JP-A) No. 2000-30394 and the like.
In the disc cartridge of JP-A 2000-30394, the entire opening is closed in a state in which the end surfaces of a first shutter member, which mainly closes the opening portion for laser head insertion (approach), and a second shutter member, which mainly closes the opening portion for insertion of the rotation spindle shaft, abut one another. In a opening state of the opening, the first shutter member and the second shutter member rotate in different directions while above mentioned abut surfaces are being apart each other. The first shutter member and the second shutter member are accommodated within accommodating spaces which substantially correspond to the projection surface area of the disc-shaped disc medium. Thus, this disc cartridge aims for a reduction in size and a reduction in thickness, while preventing adhesion of dust and the like onto the disc medium.
At one of wall surfaces of this disc cartridge, a guide groove for guiding at a time of inserting the disc cartridge into the drive device is provided in parallel to the inserting direction. A lock releasing lever of a lock mechanism which regulates (stops) movement of the shutter member, and an activating member which moves the shutter member to an opening direction protrude in the guide groove. A convex portion, which engages with the lock releasing lever and the activating member, protrudes from the drive device.
Accordingly, when such disc cartridge is inserted into the drive device, the convex portion enters in the guide groove in accompany with the insertion of the disc cartridge into the drive device. First, the convex portion abuts the lock releasing lever and a lock state of the shutter member is released. Then, when the disc cartridge is inserted further into the drive device, the convex portion abuts the activating member and the shutter member is moved in the opening direction. In this way, the opening is opened and access to the disc media becomes possible.
In this way mentioned above, the shutter member which opens and closes the opening of the disc cartridge is moved by operating the lock releasing lever and the activating member, which are disposed at the one side wall of the disc cartridge. However, in this case, because of means which can move the shutter member so as to open the opening being provided at one side wall, there is a problem that countermeasure against the shutter member being inadvertently opened does not suffice.
The object of the present invention is to provide a disc cartridge which prevents a shutter portion from being opened and closed inadvertently.
In order to achieve the above object, the disc cartridge of a first aspect of the present invention is a disc cartridge having a shutter portion which can open and close an opening for access to a disc-shaped disc medium, the opening being formed in at least one surface of a case which rotatably accommodates the disc medium, wherein two groove portions are provided at wall surfaces of the case, and an operating portion of a lock mechanism for the shutter potion is provided in one of the groove portions, and an activating portion for opening and closing operation of the shutter portion is provided in another of the groove portions.
The disc cartridge of a second aspect of the present invention is a disc cartridge having a shutter portion which can open and close an opening for access to a disc-shaped disc medium, the opening being formed in at least one surface of a case which rotatably accommodates the disc medium, the disc cartridge comprising: a first groove portion which is formed on one of wall surfaces of the case; a second groove portion which is formed on another of the wall surfaces of the case; a lock portion which regulates movement of the shutter portion; and an activating portion for moving the shutter portion, wherein the activating portion protrudes from the first groove, and an operating portion of the lock portion protrudes from the second groove.
In the disc cartridge of a third aspect of the present invention according to the second aspect, a protruding portion which protrudes from the second groove is formed at one end portion of the operating portion, and an engaging portion for engaging with the shutter portion is formed at another end portion of the operating portion.
In the disc cartridge of a fourth aspect of the present invention according to the third aspect, the shutter portion comprises a first shutter member and a second shutter member, and the activating portion is provided at an one end portion of the first shutter member and an engaged portion which is engaged with the engaging portion of the lock portion is provided at another end of the first shutter member.
In the disc cartridge of a fifth aspect of the present invention according to the second aspect, the first groove portion and the second groove portion are formed respectively at side walls, which oppose each other, of the case.
In order to open the opening intentionally, the operating portion of the lock mechanism and the activating portion for opening and closing operation of the shutter portion are operated at the same time. However, in the present invention, the operating portion and the activating portion are provided in the respective different groove portions, namely, operating of the shutter member is not facile. Accordingly, it can be prevent that the opening is opened inadvertently.
It is preferable that the case is formed by joining a top shell and a bottom shell, and the shutter portion is provided at an outer side of the case. Further, it is preferable that a covering plate portion, in which an opening corresponding to the above mentioned opening is formed, is provided, and the shutter portion is movably accommodated between the covering plate portion and the case.
Further, it is preferable that the lock mechanism (the lock portion) is structured such that a center portion of the operating portion of lock mechanism is rotatably supported, a protruding portion provided at one end of the operating portion protrudes in the one of the groove portions and an engaging portion provided at another end of the is engaged with a cut out portion formed at the shutter portion. In this way, the lock mechanism can be operated preferably. Also, because the cut out portion is a shutter window portion forming a part of the opening, due to utilizing this window portion, it becomes not necessary that another engaged portion for engaging with the engaging portion of the operating portion of the lock mechanism is provided at the shutter portion. Accordingly, the cost does not increase.