Disc cartridge

Abstract: A disc cartridge having a cartridge body accommodating therein a record medium so that the record medium can have information recorded thereon and/or reproduced therefrom in the accommodated state, a first identifying device movably provided in the cartridge body so as to be switched from the exterior of the cartridge so that it can close partly or wholly a rectangular window aperture formed through the cartridge body, and a second identifying device provided in the cartridge body in a half-secured condition so as to close a part of another rectangular window aperture formed through the cartridge body and which cannot be switched from the exterior of the cartridge, wherein the first and second identifying devices indicate the kind of optical disc and data necessary for recording and/or reproducing the optical disc incorporated.

Description: The present invention relates generally to disc cartridges and, more particularly, is directed to a disc cartridge in which a disc-shaped record medium such as a magneto-optical disc or the like is accommodated such that information can be recorded on, and/or reproduced from, the recording medium. Recently, a magneto-optical disc (hereinafter referred to as an MO disc) and an optical read-only memory (hereinafter referred to as an O-ROM disc) have become available as optical discs of 90 mm type. These optical discs are accommodated in a disc cartridge and can be recorded and/or reproduced by a head apparatus through an access opening openable and closeable by means of a shutter which is provided on the disc cartridge. EP-A-0139146, on which the precharacterising portion of appended claim 1 is based, discloses a symmetrical form of disc cartridge having identically molded halves. The cartridge comprises symmetrically located through holes having erase preventing chips projecting therein, the chips being "switchable" by breaking them out of the through holes. EP-A-0320897, which is only considered under Article 54(3) EPC and which only designates the United Kingdom, France and Germany, discloses a disc cartridge having, for each recording surface of the disc, a write protect member movably mounted on the cartridge. Let us explain a prior art disc cartridge which incorporates therein a 90 mm optical disc according to the ISO standard. Figures 1 to 3 of the accompanying drawings show an example of such a disc cartridge. In figures 1 to 3, there is shown a cartridge body 1 which is formed of an upper cartridge half 1a and a lower cartridge half 1b. A window aperture 2 is formed through the upper half la at its upper corner, whereas a rectangular window aperture 3 is formed through the lower cartridge half 1b. This rectangular window aperture 3 is formed of a window aperture portion 3a corresponding to the window aperture 2 and a window aperture portion 3b which is not corresponding to the window aperture 2. This rectangular aperture 3 is twice as long as the window aperture 2 in the length direction. A closing member 4 the size of which is ½ of that of the rectangular aperture 3 is slidably engaged with this rectangular aperture 3 between the one half portion 3a provided as the corresponding portion and the other half portion 3b provided as the non-corresponding portion, whereby the closing member 4 can be changed-over from the outside into the window aperture portion 3a or 3b so serving as identification means. The identification of the optical disc incorporated in this disc cartridge is performed by detecting the movement switching position of the closing member 4 engaged with the rectangular opening portion 3. The position of the closing member 4 can be mechanically or optically detected. From a mechanical standpoint, as shown in figure 2A, a recording and/or reproducing apparatus (not shown) is provided with a push-type switch 5 having a pair of operation members 5a and 5b which are corresponding to the one half portion 3a and the other half portion 3b of the rectangular opening portion 3 of the cartridge body 1. Accordingly, under the condition that the disc cartridge is incorporated into the recording and/or reproducing apparatus, the closing member 4 pushes the operation member 5a or 5b (in figure 2A, the operation member 5b being pushed) whereby the position of the closing member 4 is detected mechanically. From an optical standpoint, as shown in figure 2B, the recording and/or reproducing apparatus is provided with a light source 6 such as a light emitting diode (LED), lamp or the like corresponding to the window aperture 2 of upper half 1a of the disc cartridge body 1, whereas in the recording and/or reproducing apparatus photo detectors 7a and 7b are respectively provided in facing relation to the one half portion 3a and the other half portion 3b of the rectangular window aperture 3 formed at the rear surface side or the lower cartridge half 1b. In the condition that the disc cartridge is loaded onto the recording and/or reproducing apparatus, the closing member 4 is opposed to the photo detector 7a or 7b (photo detector 7b in figure 2B) so that the light emitted from the light source 6 can not be received by the photo detector 7b, whereby the position of the closing member 4 can be optically detected. When the closing member 4 is removed from the rectangular window aperture 3 of the cartridge body 1, the rectangular window aperture 3 is opened so that the position of the closing member 4 can neither be detected mechanically nor optically. As described above, in this disc cartridge, different pre-determined information can be obtained on the basis of the positions of the closing member 4, ie, as shown in figures 6A, 6B and 6C, three modes of the closing member 4 relative to the rectangular opening 3 of the cartridge body 1 are used to identify the kinds of discs incorporated in the disc cartridge. The identification is performed with respect to the existence or absence of the write-protect of the MO disc and the kind of the MO disc. As described above, in the prior art disc cartridge, three kinds of identification such as the existence or absence of the write protect mechanism and the kinds of discs such as the O-ROM disc or MO-disc can be performed by the appearance of the disc cartridge. However, the prior art disc cartridge cannot perform other necessary identification such as whether a reflecting layer is a layer having high reflectivity formed of an aluminium film or the like in the case of the O-ROM disc, whether the reflecting layer is a layer having low reflectivity corresponding to the MO-disc and whether the byte number per section is 512 bytes per sector or 1024 bytes per sector or the like. Accordingly, in order to determine whether the reflectivity of the O-ROM disc is high or low, a sample laser light must be irradiated onto a particular portion of the disc and the magnitude of amount of the reflected back light must be detected. In the above mentioned operation, when the MO disc is accommodated into the disc cartridge, there is then the risk that data on the disk may be destroyed. Further, if the identification is performed as to the unit of byte number per sector, data of a particular zone of the disc needs to be read-out to ascertain this. As described above, data, which cannot be read out from the external appearance of the disc cartridge, necessitates detection of the relevant attributes from the disc medium itself. Therefore, it is an object of the present invention to provided an improved disc cartridge which can reduce or eliminate the defects encountered with the prior art. According to the present invention, there is provided a disc cartridge comprising: (a) a cartridge body accommodating therein a disc-shaped record medium so that said disc-shaped record medium can have information recorded thereon and/or reproduced therefrom in that accommodated condition; (b) first identifying means provided in said cartridge body so that it can be switched from the exterior of the cartridge; and (c) second identifying means provided in said cartridge body; characterised in that the second identifying means is arranged such that it cannot be switched from the exterior of the cartridge, wherein the kind of a disc incorporated in said disc cartridge can be indicated by said first and second identifying means. The invention will be further described by way of non-limitative example with reference, to the accompanying drawings, in which:- Figures 1A and 1B are respectively perspective views showing an example of a prior art disc cartridge; Figures 2A and 2B are fragmentary diagrammatic views of section used to explain the above described prior art disc cartridge shown in figures 1A and 1B; Figures 3A to 3C are diagrammatic views of section used to explain an operation of the prior art disc cartridge of figures 1A and 1B; Figure 4 is a perspective view of an embodiment of a disc cartridge according to the present invention and illustrating the same in a partly exploded fashion; Figures 5A and 5B are perspective views of the embodiment of the disc cartridge of the present invention; and Figures 6A and 6B are diagrams used to explain an operation of the disc cartridge according to the present invention. An embodiment of a disc cartridge according to the present invention will hereinafter be described in detail with reference to figures 4 to 6. In figures 4 to 6, like parts corresponding to those of figures 1 to 3 are marked with the same references and therefore need not be described in detail. Also in this embodiment, similarly to the prior art, the window aperture 2 is formed on the upper cartridge half 1a of the cartridge body 1 at its corner portion whereas the rectangular window aperture 3 twice as large as the window aperture 2 in the length direction thereof is formed on the lower cartridge half 1b side. The closing member 4 is movably engaged with the rectangular window aperture 3 so that the closing member 4 can be moved between the one half portion 3a and the other half portion 3b of the rectangular opening portion by operation on the outside, thereby forming identifying means (first identifying means in this embodiment). When one closing member 4 is utilised by this first identifying means as shown in figure 3, however, of the bit patterns shown in figure 6B which will be described later, 1024 bytes per sector cannot be formed by the O-ROM disc having low reflectivity. In order to remove this defect, a pair of closing members 4 are provided in the cartridge body 1 so that they can be changed-over independently. Alternatively, a first closing member having an opening portion of a size to close the rectangular window aperture 3 and which is of a size of the rectangular window aperture 3 is attached to the cartridge body 1 so that it can be freely moveable and a second closing member which opens and/or closes the above described opening portion is movably attached to the first closing member. Accordingly, this closing member has a double-structure so that they can be suitably changed-over upon use. In this embodiment, a second identifying means is provided at the other corner portion of the cartridge body 1, ie, at the symmetrical position of the first identifying means. This second identifying means is constructed as follows. As shown in figures 4 and 5, a window aperture 12 is formed through the upper cartridge half 1a side and rectangular window aperture 13 of a size substantially twice the window aperture 12 in the length direction, ie, formed of one half portion 13a corresponding to the window aperture 12 and the other half portion 13b which is not corresponding to the window aperture 12 is formed on the lower cartridge half 1b side. A closing frame member 14 which can selectively close about one half portion of the rectangular aperture 13 or one half portion 13a provided as the corresponding portion and the other half portion 13b provided as the non-corresponding portion is engaged to the inner surface side of the rectangular window aperture 14 in the half-secured condition. This closing frame member 14 is engaged with the inner surface side of the rectangular window aperture 13 in the half-secured condition as follows. A frame wall 15 surrounding the peripheral edge of the rectangular window aperture 13 at a predetermined spacing is formed on the inner surface of the lower cartridge half 1b, and engaging protrusions 16a, 16b are inwardly, protrusively formed on the central portions of the two sides of the frame wall 15 in the longitudinal direction, whereby the closing frame member 14 is engaged under pressure into each of the half spacing portions surrounded by the frame wall 15 and the engaging protrusions 16a, 16b. When the closing frame member 14 is engaged with each of the half portions of the frame wall 15, one half portion 13a and the other half portion 13b of the rectangular opening portion 13 are closed respectively. Detecting means is provided on the recording and/or reproducing apparatus in association with the second identifying means constructed as above. This detecting means may be mechanical means or optical means similarly to that described above with reference to figures 1 to 3. The disc cartridge of this embodiment constructed as described above is provided with the second identifying means in addition to the identifying means of the prior art. When the two identifying means are used in the combined state, various items of information can be indicated at the same time. When the disc shaped record medium accommodated in this disc cartridge is an optical disc or magneto-optical disc, in addition to the identification of the existence or absence of the write protect mechanism of the MO-disc and the identification whether the disc is the O-ROM disc or the MO-disc, it becomes possible to identify whether the reflectivity of the O-ROM is high or low, the byte number per sector and so on. More specifically, as shown in figure 6A, assuming that a is the one half portion 3a of the rectangular window aperture 3, b is the other one half portion 3b of the rectangular window aperture 3 provided as the first identifying means, c is the one half portion 13a of the rectangular window aperture 13 and d the other one half portion 13b of the rectangular window aperture 13 provided as the second identifying means, then the combination of removing or moving the closing member 4 and the closing frame member 14 provides items of information which may be considered to be various bit patterns as shown in figure 6B. Therefore, the recording and/or reproducing apparatus detects the conditions of the thus formed first and second identifying means by the switch such as an electrical, mechanical or optical detecting means provided within the recording and/or reproducing apparatus and carries out the proper recording and/or reproduction by switching the setting of laser power of photo pickup head or the like on the basis of the detected output from the detecting means. Further, the frame closing member 14 in the second identifying mans is half-secured to the cartridge body 1 so that, when it is delivered, the frame closing member 14 is placed in the predetermined condition. Accordingly, the user is inhibited from operating the frame closing member 14 freely with ease unlike the closing member 4 of the first identifying means. Thus, the user is permitted to operate only the first identifying means. As set forth above, according to the present invention, since various items of information such as the kinds and functions of disc-shaped record medium accommodated in the disc cartridge can be identified from the outside appearance of the disc cartridge, the load on the electrical circuitry and the hardware of the recording and/or reproducing apparatus can be reduced, and mis-operation can be prevented, so considerably increasing reliability. Having described a preferred embodiment of the invention with reference to the accompanying drawings, it is to be understood that the invention is not limited to that precise embodiment and that various changes and modifications could be effected by one skilled in the art without departing from the scope of the invention as defined in the appended claims.

Claims: A disc cartridge comprising: (a) a cartridge body (1) accommodating therein a disc-shaped record medium so that said disc-shaped record medium can have information recorded thereon and/or reproduced therefrom in that accommodated condition; (b) first identifying means (2,3,4) provided in said cartridge body (1) so that it can be switched from the exterior of the cartridge (1); and (c) second identifying means (12,13,14) provided in said cartridge body (1); characterised in that the second identifying means (12,13,14) is arranged such that it cannot be switched from the exterior of the cartridge, wherein the kind of a disc incorporated in said disc cartridge can be indicated by said first (2,3,4) and second (12,13,14) identifying means. A disc cartridge according to claim 1, wherein said first (2,3,4) and second (12,13,14) identifying means indicates data necessary for recording and/or reproducing the record medium in said disc cartridge. A disc cartridge according to claim 1, wherein at least one of said first (2,3,4) and second (12,13,14) identifying means indicates whether or not recording can be carried out on the record medium in the cartridge. A disc cartridge according to claim 1, wherein at least one of said first (2,3,4) and second (12,13,14) identifying means indicates the recording capacity of the record medium incorporated in the cartridge. A disc cartridge according to any one of the preceding claims, wherein said first identifying means (2,3,4) includes a closing member (4) which is movably provided in said cartridge body (1) so that it can partly or wholly close a rectangular window aperture (2,3) formed through said cartridge body (1). A disc cartridge according to claim 5, wherein said second identifying means (12,13,14) includes a closing frame member (14) half-secured to said cartridge body (1) so that it can close at least one portion of another rectangular window aperture (12,13) formed through said cartridge body (1).

Inventors: ARAI SHIZUO, YAMAMOTO HIROSHI, ARAI, SHIZUO, YAMAMOTO, HIROSHI
Applicants: SONY CORP, SONY CORPORATION
Application year: 1990
Main classification: G11B23
IPC codes: G11B23, G11B19, G11B11