Abstract:
A disk apparatus for use in a disk cartridge system including different types of disk cartridge. The disk cartridge system has a first disk cartridge and a second disk cartridge. The first disk cartridge including a first case having a substantially rectangular shape with first, second, third and fourth edges, and at least one of a first groove in both of the second and third edges, and a first cutout portion in both of the second and third edges and passing through a thickness of the first case. The second disk cartridge includes a second case having a substantially rectangular shape with fifth, sixth, seventh and eighth edges, the fifth edge of the second case being delimited by a fifth corner portion connecting the fifth edge and sixth edge, and at least one of a second groove located in only one of the sixth and seventh edges and a second cutout portion located in both of the sixth and seventh edges without passing through a thickness of the second case. A length, width and thickness of the first case are substantially equal to a length, width and thickness of the second case and a diameter and thickness of the first disk are substantially equal to a diameter and thickness of the second disk. The disk apparatus having a discrimination arrangement which discriminates at least one of the groove and the cutout portion.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This is a continuation of U.S. application Ser. No. 09/400,846, filed Sep. 21, 1999, U.S. Pat. No. 6,075,763 which is related to Ser. No. 09/400,847, filed Sep. 21, 1999, and which are continuations of U.S. application Ser. No. 08/603,162, filed Feb. 20, 1996, U.S. Pat. No. 5,991,260 the subject matter of which is incorporated by reference herein. 
    
    
     The present invention relates to a disk cartridge, a disk cassette, a disk caddy, a disk half or a disk case for housing a disk-shaped recording medium such as an optical disk, and a disk device using the same. 
     BACKGROUND OF THE INVENTION 
     A compact disk (hereinafter, referred to as “CD”) system, which has been standardized in the so-called “red book”, the so-called “yellow book” or the like and in which information is recorded in a disk having a diameter of 120 mm, and which is used mainly for music information has been widely adopted. This system has an almost sufficient capacity for handling music in formation, but when recording video information as in a CD-ROM, its capacity becomes insufficient for an increased amount of information, thus resulting in insufficient recording time or degraded image quality. Attempts to deal with this problem includes, for example, a digital video disk (hereinafter referred to as “DVD”) system and the like. 
     In the aforementioned CD system, the disk is mainly used on only one side or face for exclusive reproduction. Also, the disk is often handled in a bare state, and a tray loading system, in which the disk is mounted on a drawer-shaped tray coming out from a disk device, is mainly used because of its good operability. On the other hand, however, a disk cartridge, which is called a CD caddy, as described in Japanese Laid-Open Patent Application No. 63-153376 and in Japanese Laid-Open Patent Application No. 63-47472, capable of taking a disk out and in, is used, and a front loading system for inserting this disk cartridge into the device is also utilized. 
     In addition, in the aforementioned DVD system, the disk is used on both sides or faces for recording and/or reproduction. The disk tends to be housed in an exclusive cartridge primarily for protection from the standpoint of securing the reliability resulting from higher density recording. 
     Further, in contrast to the CD system, which is mainly used for exclusive reproduction, there has also been announced a PD (Phase-change Disk) system capable of rewriting, as described in Optical Disk System for Multimedia National Technical Report, Vol. 4, No. 6, December 1994, pgs. 129-136. In this PD system, the disk is used on one side for recording and/or reproduction. Also, the disk is housed in an exclusive cartridge from the standpoint of securing the reliability resulting from rewriting. 
     Disks for use with each system of the aforementioned CD, DVD and PD all have a diameter of 120 mm, and cartridges for each system described above are of nearly the same shape, having the same dimensions. 
     The problem to be solved by the present invention is to increase the capacity of the CD system or a disk system having nearly the same dimensions as the CD system, and the concept and technical problems for the disk cartridge and disk device using the same to deal with the problem are described below. 
     1) In order to take measures against scratching, dust and dirt resulting from higher density recording, a state in which a disk has been placed in a cartridge is supposed to be a standard. Even in the CD system, there is present a case called a “CD caddy” which is about 135 mm long, about 125 mm wide and about 8 mm thick, but this CD caddy is not used currently. Rather, the so-called tray loading system is mainly used. 
     2) Allowing both faces of the disk to be recorded. The CD is for one side recording and the capacity can be doubled by simple calculation. 
     3) Making a disk which is CD compatible and reproducible In a disk device using a new disk cartridge, its sales point is to make the existing CD compatible and reproducible. Accordingly, it is an indispensable condition to enable taking a disk in and out and having a disk for CD system within. However, the CD caddy is for one-side recording, and a clamper of the disk is attached on the side of the caddy case. The clamper is constructed to be on the side of the disk device because the new disk cartridge is of a both-face recording system. Thus, if the CD caddy is mounted to a disk device for the new disk cartridge, two clampers will interfere with each other. Therefore, it is necessary to prevent the CD caddy from being mounted to the disk device of the new disk cartridge. 
     4) Supply of the disk and disk cartridge at a low price. In order to reduce the price for general family usage, the disk cartridge including the disk device is required to be constructed at low cost. 
     Further, when increasing the capacity as described above, the mixed existence of three similar disk cartridges poses the following problems. 
     5) Discrimination of disk cartridges for each system 
     6) Prevention of erroneous insertion 
     7) The system of mounting the cartridge to the device is made applicable to both the front loading system and the tray loading system. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to solve the above-described problems, and to provide a disk cartridge with increased capacity and capable of discrimination from similar and different disk cartridges, and a disk device using the same. 
     In order to solve the aforementioned problems, a disk cartridge and a disk device using the same according to the present invention including the following features. 
     1) A shutter for the disk cartridge is utilizable for both faces of the disk and is slidable in opposite directions with the structure of the disk cartridge being arranged so that the disk can be taken in and out. Also, the case of the disk cartridge is provided with a structure to prevent a cartridge of a different kind such as the CD caddy from being erroneously inserted. 
     2) A biasing arrangement for the shutter is provided at a position of the cartridge where the window of the case is closed. 
     3) When the disk is taken in and out, the structure of the disk cartridge is arranged to open at least a part thereof which is in a plane parallel to a plane of the disk. 
     4) When the disk is taken in and out, the structure of the disk cartridge is arranged to open a portion of the case at a position other than within a shutter moving range. 
     5) A disk conforming to the compact disk standards is enabled to be incorporated within the disk cartridge. 
     6) For biasing the shutter, one each of a torsion spring whose both arm portions directly engage with the case and the shutter is arranged in the corner areas on both sides of the disk cartridge across the shutter in a state in which the window of the case is closed. 
     7) A disk plane discrimination arrangement is provided which is capable of discriminating whether the plane of the disk on which recording and/or reproduction is performable on one side or both sides of the disk. 
     8) A disk plane specifying arrangement is provided which is capable of specifying which is the plane of the disk on which recording and/or reproduction is performable. 
     9) A discrimination arrangement for discriminating different kinds of disk cartridges is provided. 
     10) For discrimination or improper insertion prevention, a first cutout portion formed by cutting out at least a part of an outer plane of the disk cartridge which extends parallel to the disk plane of the disk for the disk cartridge of a different type, and a second cutout portion formed by cutting out at least a part of the outer plane of the disk cartridge which extends in a direction orthogonal to the disk plane for the disk cartridge of a different type. 
     11) The first cutout portion is arranged laterally symmetrically with respect to the inserting direction into a disk device. 
     Each of the aforementioned items 1) to 11) acts in the following manner as described in 1) to 11), respectively. 
     1) Even when the disk cartridge, which is applicable to both faces of the disk, is turned over for insertion to apply it to both faces or sides of the disk, it is made applicable by using one shutter open-and-close mechanism, thus making the disk within the cartridge replaceable. 
     2) Even if the shutter is intentionally opened, releasing the opening force automatically closes the shutter. 
     3) During opening, the disk plane can be easily seen, and the handle ability for taking the disk in and out is improved. 
     4) Any interference between the shutter and the opening structure is avoided. 
     5) A disk conforming to the compact disk standards is mountable to a disk device for new disk cartridges. 
     6) Manufacture of a shutter having a long stroke capable of opening in opposite directions by using a thin cartridge constructed with a small number of parts is enabled. 
     7) Easy recognition of whether the recording plane of the disk is on one side or both sides is enabled. 
     8) Easy recognition of which side is the recording plane of the disk is enabled. 
     9) Discrimination from any cartridge of a different type having nearly the same diameter is enabled. 
     10) For mounting a cartridge to the disk device, application to the front loading system and/or the tray loading system is enabled. 
     11) Even if the cartridge is inserted upside down into the device to apply it to both-face or side recording, it is possible to discriminate by one discrimination arrangement provided on the side of the device. 
     These and other objects, features and advantages of the present invention will become more apparent from the following description when taken in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIGS.  1 ( a )- 1 ( d ) show a plan view and side views of a disk cartridge according to the present invention. 
     FIG. 2 is a plan view showing a state in which the insertion of a disk cartridge according to the present invention into a disk device has been started. 
     FIGS.  3 ( a ) and  3 ( b ) show a plan view and a side view of a state in which the insertion of a disk cartridge according to the present invention into the disk device has been completed. 
     FIGS.  4 ( a )- 4 ( c ) show views of construction of different forms of a discrimination hole provided for the shutter in a disk cartridge according to the present invention. 
     FIGS.  5 ( a ) and  5 ( b ) show a is a plan view and a side view of the construction of a discrimination hole or cutout provided in the case for a disk cartridge according to the present invention. 
     FIGS.  6 ( a )- 6 ( d ) show alternative constructions of a discrimination hole or cutout provided in the case for a disk cartridge according to the present invention. 
     FIG. 7 is a perspective view showing a disk cartridge according to another embodiment the present invention for a tray loading system. 
     FIG. 8 is a perspective view showing a conventional CD caddy. 
     FIG. 9 is a perspective view showing a disk cartridge of a PD system in accordance with the present invention. 
     FIG. 10 is a perspective view showing a disk cartridge and a disk device according to the present invention. 
     FIGS.  11 ( a ) and  11 ( b ) show a plan view and a side view of a disk cartridge and a disk device according to the present invention. 
     FIGS.  12 ( a ) and  12 ( b ) show a plan view and a side view of a disk cartridge of the PD system and a disk device according to the present invention. 
     FIGS.  13 ( a ) and  13 ( b ) show a plan view and a side view of a disk cartridge of the PD system and a disk device according to the present invention where the disk cartridge is improperly inserted. 
     FIGS.  14 ( a ) and  14 ( b ) show a plan view and a side view of the CD caddy and a disk device according to the present invention where the CD caddy is attempted to be inserted. 
     FIGS.  15 ( a ) and  15 ( b ) show a plan view and a side view of the outside dimensions of a disk cartridge according to the present invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to the drawings wherein like reference numerals are utilized to designate like parts, a first embodiment according to the present invention is described in conjunction with FIGS. 1 to  6 , which embodiment corresponds to the so-called front loading system. FIGS.  1 ( a )- 1 ( d ) show a disk cartridge according to the present invention, with FIG.  1 ( a ) being a partially exploded plan view, and FIGS.  1 ( b ),  1 ( c ) and  1 ( d ) being side cross-sectional views as viewed from below, from the right side and from above, respectively. 
     A disk cartridge  100  according to the present invention is basically constituted by a disk  1  for recording information, a case formed by case portions  2  and  3  for housing the disk, a shutter  4  for opening and closing windows  2   a  and  3   a  in the case two springs  40  and  41  for biasing the shutter  4  and a door  5  for opening a part of the case. The disk  1  is capable of recording and reproducing a signal on both faces or sides thereof. 
     The case is formed divided into two sheets represented as case portions  2  and  3  sheets which are bonded together. Each of the case portions is formed with a window  2   a  or  3   a  which exposes a part of the disk plane so as to record and reproduce information. Dust-proof barrier plates  2   p  and  3   p  are formed between the disk  1  and the springs  40  and  41 . 
     The shutter  4  is integrally formed as a U-shaped character with shutter planes  4   a  and  4   b  corresponding to the both faces of the disk respectively, and a side portion  4   c , which integrally connects both shutter planes. Projections  4   p  and  4   q  engage with a guide groove  2   g  linearly formed in the case so that the shutter is linearly slidable in the right and left directions in the figure. 
     The two springs  40  and  41  may be torsion springs which are in a stretched state or helical tension springs, and exert a biasing force so that the shutter planes  4   a  and  4   b  of the shutter  4  maintain the windows  2   a  and  3   a  at their closing positions respectively. These two springs have the same shape so as not to increase the number of the parts and enabling a cost reduction. Each of these springs shown as torsion springs is mounted at two corner regions  50  and  51 , respectively, which regions are provided between the two case  2  and  3 , and which laterally sandwich the shutter  4  therebetween. The leading end of the arm of each of the respective springs is bent at a right angle to the axial direction of the coil portion, and each end  40   a  or  41   a  engages with a groove portion  2   d  or  3   d  at the case corner. Also, each of the other ends  40   b  or  41   b  engages with a stopper  3   p  or  3   q  having a V-shaped cross-section (see FIG.  3 ( a )) formed in the case portion  3  so that the springs are positioned with high precision in the up-and-down and the right-and-left directions in the figure because they are in the stretched state as described above. In this respect, according to the present invention, the torsion spring is constructed so that both ends thereof directly engage with the case without using other parts therebetween, thus not increasing the number of parts. Hooks  4   d  and  4   e  are integrally formed with the shutter  4  in coincidence with the above-described up-and-down and right-and-left positions of the torsion springs and with a deviation in height of the disk in the direction of thickness thereof, and innermost recesses in the grooves of the hooks  4   d  and  4   e  are positioned respectively. Thereby, the shutter  4  is retained at the central position shown in the right-and-left direction, i.e., the sliding direction in the figure. 
     In this respect, the sides of the case portions  2  and  3  as viewed from the direction of FIG.  1 ( b ) are constructed to be opened, through which it is possible to insert these two springs once in one direction in a bent state for use in the cartridge and representing a very excellent assembly property. 
     A door  5  pivotally engages with the case  2  at pivot points  5   a ,  5   b  to open so that the disk can be taken in and out as shown by dotted lines of  5   c  and  1   a  in FIG.  1 ( c ). Since the door  5  has a portion extending in a plane in parallel to the disk plane and this portion is opened, the disk has good visibility and good taking-in-and-out property when the door is opened. In this respect, the door  5  may be constructed to open at the side of the case in a manner similar to the cartridge for an 8 cm CD-ROM which is currently on the market. Also, when a disk such as, for example, a rental disk should not be taken out of the disk cartridge, the door  5  may be eliminated for preventing removal of the disk by a renter. 
     The operation when the shutter opens and closes the window is described with reference to FIG.  2  and FIGS.  3 ( a ) and  3 ( b ). In FIG. 2, when the disk cartridge  100  is inserted into a disk device  200  (a downward direction in the figure), a shutter opening lever  201  of the disk device  200  is supported by a pivot shaft  202  fixed on the device side, is biased clockwise in the figure by the spring  203 , and stands by in contact with a stopper  204  so that the leading end  201   a  of the shutter opening lever  201  abuts an end  4   r  of the side portion of the shutter  4 . When the disk cartridge is further inserted into the interior of the device  200  from this state, the shutter opening lever  201  rotates counterclockwise in the figure so as to cause the shutter  4  to slide toward the left side in the figure. When the sliding is started, the right-hand end  40   b  of the left-hand spring  40  is urged against the groove in the left-hand hook  4   d  in the shutter, as shown in FIG.  3 ( a ), to engage therewith and to retract from the projection  3   p  of the case. On the other hand, while it is remaining urged against and engaged with the projection  3   q  of the case, the left-hand end  41   b  of the right-hand spring  41  in the figure retracts from the right-hand hook  4   e  in the shutter with the right-hand spring  41  retained as it is. With the sliding of the shutter  4 , the right-hand end  40   b  of the left-hand spring  40  linearly moves to be deformed within the corner region  50 , as shown in FIG.  3 ( a ). On the side portion  4   c  of the shutter  4 , there is provided a discrimination hole  4   s  (as shown more clearly in FIG.  3 ( b )), and at the position where the disk cartridge  100  has been inserted to the innermost position, a projection  210  is provided on the side of the disk device  200  correspondingly to the discrimination hole  4   s  such that the insertion of the disk cartridge  100  can be completed only when the projection  210  fits in the discrimination hole  4   s . Then, a sensor (not shown) detects that the disk cartridge could be inserted to the completion position, and thereafter the entire disk cartridge  100  is moved toward the revolving shaft for the disk to complete the mounting of the disk so as to enable recording and/or reproduction by the disk device. 
     In the case of a CD caddy which does not have the discrimination hole  4   s , the corresponding side portion  4   c  of a shutter  4  and the leading end of the projection  210  of the disk device collide with each other before the completion of insertion, thus preventing completion of the insertion. Thereby, the mounting of a CD caddy to the disk device is prevented. 
     In this respect, according to the present invention, the disk cartridge  100  is constructed laterally symmetrically in the state of FIG.  1 . FIGS.  4 ( a )- 4 ( c ) and FIGS.  6 ( a )- 6 ( d ) are side views showing the external shape of the case portions  2  and  3  and the shutter  4 . In FIG.  4 ( a ), the discrimination hole  4   s  is formed at the center of the side portion  4   c  of the shutter  4  to show a point symmetry therein. When the disk cartridge  100  is turned over for insertion, the design is such that quite the same operation, as shown in FIG. 2 or FIGS.  3 ( a ) and  3 ( b ), can be performed when recording and reproducing on the rear or opposite plane thereof, and the mechanism on the side of the disk device  200 , as shown in FIG. 2 or FIGS.  3 ( a ) and  3 ( b ), is capable of coping with the both faces of the disk only by one mechanism, thus achieving the simplified structure of the device and the reduced cost. Although the discrimination hole  4   s  is rectangular in the present embodiment, as shown in FIG.  4 ( a ), it may be circular or the like, as shown in FIG.  4 ( b ). Also, if a point symmetry is shown at the side portion  4   c  of the shutter  4  as described above, there may be a plurality of holes, as shown in FIG.  4 ( c ). Also, on the orthogonal plane on the front edge side of the case portions  2  and  3  in the inserting direction, there may be provided cutout portions  20   a  and  20   b  so as to show a point symmetry on the orthogonal plane on the front edge side, as shown in FIGS.  5 ( a ) and  5 ( b ), so that a projection  210   a  is fitted correspondingly thereto. In addition, the cutout portion  20  is sufficient to show a point symmetry, and such layouts, as shown in FIGS.  6 ( a )- 6 ( d ), may be used. 
     Of the case external dimensions, the width, which is a frontage dimension for insertion into the device, and/or the thickness may be smaller than those of the CD caddy as the cartridge which should be prevented from being inserted. 
     For the disk utilized for one-side recording, only one of the cutout portions  20   a  and  20   b  which corresponds to the recording surface is formed, whereby it becomes possible to discriminate from both-face recording, and to further specify which face is the recording plane. 
     As regards a combination of the cutout portion of a particular shape and a corresponding projection, all detection arrangements including, for example, the following items can be substituted if a layout thereof is arranged to show a point symmetry on the orthogonal plane on the front edge side. 
     1) A combination of a light emission diode using an optical arrangement and a light receiving element. 
     2) A combination of a MR sensor using a magnetic arrangement and a magnet. 
     3) A combination of a ultrasonic wave oscillator using an acoustic arrangement and its receiver. 
     4) A combination of a contact switch using an electric arrangement and conductive material. 
     In this respect, when the disk cartridge  100  is taken out from the disk device  200 , the operation is performed conversely to the foregoing, and in FIG. 1 to FIGS.  3 ( a ) and  3 ( b ), the right-hand end  40   b  of the left-hand spring  40  returns to a state where it is urged by the projection  3   p  of the case portion  3 . 
     The construction using a torsion spring as the biasing arrangement for the shutter in the present embodiment may be such that one helical tension spring is arranged in a region in which no disk is arranged within the case in a manner to the CD caddy which is currently on the market, and which is occupied by the shutter located in a position where the window is closed. 
     FIG. 7 shows a second embodiment according to the present invention, wherein this embodiment corresponds to a disk device of the tray loading system in addition to the front loading system in the previously described embodiment. FIG. 7 shows a schematic external shape of the disk cartridge, and its interior and shutter structure are the same as those for the previously described first embodiment, but the disk taking-in-and-out structure is not adopted. As the discrimination arrangement and the erroneous insertion prevention arrangement in the front loading system, the cutout portions or grooves  20   a  and  20   b  structured in a manner similar to that shown in FIG.  6 ( a ) are formed. In addition thereto, for discrimination and erroneous insertion prevention in the tray loading system, a plane parallel to the disk plane of the disk cartridge  100  is opened on both sides, and the cutout portions  302   a  and  302   b , which pass through in its direction of thickness, are laterally symmetrically provided on the both sides correspondingly to the aforementioned cutout portions  20   a  and  20   b  respectively. 
     FIG. 8 is a perspective view of a conventional CD caddy. As shown, the conventional CD caddy  400  has no cutout portions open in a plane parallel to the disk plane. On the other hand, in FIG. 9, which is a perspective view of a disk cartridge  500  for the PD system, there are additionally provided, in accordance with the present invention, cutout portions  502   a  and  502   b  where one side of a plane parallel to the disk plane of the disk cartridge  500  has been opened correspondingly to the side of the recording plane of the one-side recording disk. In FIG. 10, reference numeral  200  designates a disk device;  251 , a tray thereof; and  250 , a draw-in command button for giving a command to start the tray draw-in operation. In the tray  251 , two projections  252   a  and  252   b  are provided at positions and shapes corresponding to the cutout portions  302   a  and  302   b.    
     FIGS.  11 ( a ) and  11 ( b ) show a construction in which a disk cartridge according to the present invention is mounted to the disk device with FIG.  11 ( a ) being a plan view and FIG.  11 ( b ) a side cross-sectional view. In FIG.  11 ( a ), the two projections  252   a  and  252   b  provided in the tray  251  coincide with the cutout portions  302   a  and  302   b  provided in the disk cartridge  100  in both position and shape respectively for fitting in, and the tray  251  lowers to the lowest position thereof as shown in FIG.  11 ( b ) to complete the mounting. In this state, the front of the draw-in command button  250  is accessible to permit the button to be pressed. In this respect, the disk according to the present invention can be used on both faces thereof. As described above, the projections  252   a  and  252   b  provided in the tray  251  and the cutout portions  302   a  and  302   b  provided in the disk cartridge  100  are laterally symmetrically provided respectively, and the cutout portions  302   a  and  302   b  are constructed so that the plane parallel to the disk plane of the disk cartridge  100  is opened on both sides to pass through in its direction of thickness, whereby the mounting can be completed in quite the same manner, even when the disk cartridge  100  is turned over to use its reverse side. 
     The construction in which the disk cartridge for the PD system, as shown in FIG. 9, is mounted is described with reference to FIGS.  12 ( a ) and  12 ( b ) and FIGS.  13 ( a ) and  13 ( b ). The disk for the PD system is used only on one side. FIGS.  12 ( a ) and  12 ( b ) show the construction when the disk cartridge is properly mounted with respect to the plane for use in the disk device with FIG.  12 ( a ) being a plan view and FIG.  12 ( b ) being a side cross-sectional view. In FIG.  12 ( a ), the two projections  252   a  and  252   b  provided in the tray  251  coincide with the cutout portions  502   a  and  502   b  provided in the disk cartridge  500  in position, shape and height (depth) respectively for fitting in, and the tray  251  lowers to the lowest position thereof as shown in FIG.  12 ( b ) to complete the mounting. In this state, the front of the draw-in command button  250  is accessible to permit the button to be pressed. 
     On the other hand, FIGS.  13 ( a ) and  13 ( b ) show a construction when the disk cartridge of FIG. 9 has been erroneously mounted to the disk device with its plane for use reversed with FIG.  13 ( a ) being a plan view and FIG.  13 ( b ) being a side cross-sectional view. In FIG.  13 ( a ), the two projections  252   a  and  252   b  provided in the tray  251  cannot fit into the cutout portions  502   a  and  502   b  provided in the disk cartridge  500  so that the upper portion thereof cannot reach the lowest position of the tray  251  in FIG.  13 ( b ). Accordingly, the mounting cannot be completed. In this state, the draw-in command button  250  is arranged so that the front thereof is rendered inaccessible by the disk cartridge  500  to prevent the button from being pressed. 
     In this manner, 
     1) The disk cartridge  500  cannot be accurately mounted. 
     2) Since the disk cartridge  500  is constructed to be inclined at this time, it is easy to recognize an abnormality. 
     3) The draw-in command button cannot be pressed. 
     By the foregoing arrangements, the operator is securely notified of the erroneous insertion. Also, the discrimination is provided ahead of the disk cartridge  500  in the inserting direction into the disk device  200 , it is: 
     1) easy to recognize that the disk cartridge  500  cannot enter because the side of the disk cartridge near the inlet of the device is raised to deviate from the inlet; and 
     2) easy to use it also as a gripper for holding the disk cartridge  500  which is often provided in the same position. 
     Such effects as described above can be also obtained if in the two corner regions  50  and  51  of the disk cartridge as shown in FIG.  1 ( a ), which are covered by the movement of the shutter  4 , there are provided the discrimination arrangement, so that the discrimination arrangement is utilized for both the front loading system and the tray loading system. The remaining two corner regions of the disk cartridge can be left opened, and this leads to the effect that they can be utilized effectively and provided with a margin having, for example, a reference hole, a disk taking-in-and-out mechanism, or the like. Since the discrimination arrangement is provided at only one side with respect to of the position of the disk center, the discrimination arrangement for the front loading needn&#39;t increase the width of the disk cartridge, and this leads to the effect that the disk cartridge can be smaller in size. 
     FIGS.  14 ( a ) and  14 ( b ) show a construction when the CD caddy  400  which must not be mounted in the tray loading system has been erroneously mounted to the disk device with FIG.  14 ( a ) being a plan view and FIG.  14 ( b ) being a side cross-sectional view. Even if mounted with either side of the plane turned upward, the two projections  252   a  and  252   b  provided on the tray  251  in FIG.  14 ( a ) cannot fit in the CD caddy  400 , and the mounting cannot be completed in a manner similar to that of FIG.  13 ( b ), thus preventing the draw-in command button  250  from being pressed. Such erroneous insertion can be securely avoided. 
     In this respect, for all the aforementioned three types of disks, it goes without saying that the structure is arranged to prevent the erroneous insertion even when an attempt to mount the disk cartridge is made in a state where it has been rotated by 90° or 180°. 
     FIGS.  15 ( a ) and  15 ( b ) show approximate outside dimensions of the disk cartridge according to the present invention with FIG.  15 ( a ) being a plan view and FIG.  15 ( b ) being a side view. In FIG.  15 ( a ), reference numerals  150  and  151  denote the reference holes of the disk cartridge. The letter designations A-L in FIGS.  15 ( a ) and  15 ( b ) have the following dimensions: 
     A=125 mm 
     B=137 mm 
     C=115 mm 
     D=4 mm 
     E=0.7 mm 
     F=2 mm 
     G=102.5 mm 
     H=12 mm 
     I=10 mm 
     J=5 mm 
     K=8 mm 
     L=3 mm 
     According to the present invention, it is possible to provide a mass storage disk cartridge at low cost in the CD system or the disk system having the substantially same dimensions as it, and there is also provided the effect that it is possible to securely discriminate any disk cartridge of a different type having substantially the same shape. 
     While we have shown and described several embodiments in accordance with the present invention, it is understood that the same is not limited thereto but is susceptible of numerous changes and modifications as known to those skilled in the art, and we therefore do not wish to be limited to the details shown and described herein but intend to cover all such changes and modifications as are encompassed by the scope of the appended claims.