Abstract:
A disc cartridge has an optical disc ( 13 ), first and second halves ( 15 ), ( 16 ) and a slide shutter ( 14 ), in which the slide shutter ( 14 ) is removably supported between the first and second halves ( 15 ) and ( 16 ), whereby it is possible to prevent erroneous opening and closing operations by making it difficult for a user&#39;s hand to touch as well as to prevent a loss of an information record by such an arrangement which is difficult for minute trash and dust to intrude.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a disc cartridge which rotatably accommodates in a cartridge housing a disc shaped storage media such as an optical disc, a magnetic disc, a magneto-optical disc and the like capable of recording (writing) and/or reproducing (reading) an information signal such as audio information, video information or computer data information and the like. 
     2. Description of the Related Art 
     In recent years, as a disc cartridge which rotatably accommodates in a disc cartridge housing a disc shaped storage medium such as a magneto-optical disc or the like, for example, what is shown in FIG. 16 has been generally known. A cartridge disc  1  is one so called an MD (mini-disc) with a disc shaped storage medium of 64 mm in diameter being built therein. Of the MD 1 , there are a reproduction only MD and a recording and/or reproducing MD. The recording and/or reproducing MD is comprised of a cartridge housing  2  and a magneto-optical disc  3  while the reproducing only MD is comprised of a cartridge housing and an optical disc. 
     FIG. 16 is a perspective view of the MD 1  seen from a reverse side and the cartridge housing  2  thereof comprises upper and lower halves  2   a  and  2   b  which are superposed each other and the magneto-optical disc  3  is rotatably accommodated in a disk accommodation room which is formed in both the upper and lower halves  2   a  and  2   b . The upper and lower halves  2   a  and  2   b  are made square shaped when seen from the front and nearly at the central portion of its one side are respectively provided opening windows  4  penetrating in an up to down direction. These opening windows  4  are extended to nearly a central portion of the cartridge housing  2  and are made capable of being opened and closed by a slide shutter  5 . 
     The slide shutter  5  is U-shaped in cross-section comprising an upper shutter tab  5   a  for closing the opening window  4  provided in the upper half  2   a , a lower shutter piece for closing the opening window provided in the lower half  2   b  and a side piece  5   b  for connecting both the shutter pieces. Then, the cartridge housing  2  is provided with a lock mechanism for locking the slide shutter  5  when the opening window  4  is in a state of being closed. Also, nearly at a central portion of the lower half  2   b  is provided a central hole  6  for exposing a hub plate  3   a  of the magneto-optical disk  3 , with the central hole  6  being always opened. 
     The MD 1  having such an arrangement is, with the lower half  2   b  in a state of facing downward, inserted into a cartridge inserting mouth of a disc recording and/or reproducing apparatus from an arrow mark direction X. Consequently, the locking by the rock mechanism is released by a manipulating pin provided in the disc recording and/or reproducing apparatus and the manipulating pin as it is, slides the slide shutter  5  in an opposite direction to the arrow mark direction X. As a result, the opening windows  4  are opened, thereby making it possible to insert an optical head of an optical pick-up device in the opening windows  4 . 
     However, since the conventional disc cartridge has been constituted such that the cross-section U-letter shaped slide shutter  5  fits in the outside of the cartridge housing as well as the shutter piece  5   a  are respectively slid on the outsides of the upper and lower halves  2   a  and  2   b  to open and close the opening windows  4 , clearances tend to be easily in place due to curling of the free end side of the shutter pieces  5   a , thereby incurring a problem that minute trash and dust tend to easily enter into the cartridge housing  2  from the clearances. In this case, with an information storage medium with a large information capacity, the influence of the minute trash and the dust can not be negligible and when it is impossible to prevent the intrusion of the minute trash or the dust, there is a fear that the information storage surface of the disc shaped storage medium is damaged by the minute trash or the dust. When the information storage surface is damaged, it becomes impossible to read and write a normal information signal. 
     With the conventional disc cartridge, since the slide shutter  5  is in place which is easily touched by the hand of a user, there is a fear that the user accidentally opens the slide shutter  5 . When the user accidentally opens the slide shutter  5  in this manner, the influence of the trash and dust becomes increasingly larger with the higher density of the information record and hence, there have been problems that a loss of and the damage to an information record are feared to occur by the existence of the trash and dust. 
     SUMMARY OF THE INVENTION 
     The present invention is implemented in view of such conventional problems and its object is to provide a disc cartridge which has such an arrangement to prevent erroneous opening and closing operations by making it difficult for the hand of a user to touch it as well as for the minute trash and dust to intrude thereinto, thereby making it possible to avoid the loss of the information record caused by the minute trash and dust. 
     According to a first aspect of the present invention, there is provided a disc cartridge for accommodating a disc-shaped storage medium in which at least one of recording or reproducing of an information signal is carried out by a head unit of a pick-up device, which comprises a pair of halves superposed upon each other for forming a disc accommodation room for rotatably accommodating the disc-shaped storage medium, and a shutter member capable of opening and closing an opening window which is provided in at least one half out of a pair of the halves and into which a head unit can be inserted, wherein the shutter member is movably supported between the pair of the halves. 
     According to a second aspect of the present invention, there is provided a disc cartridge, wherein a shutter supporting body for supporting a free end side of the shutter member is provided between the pair of halves. 
     According to a third aspect of the present invention, there is provided a disc cartridge, wherein the shutter supporting body is an inner case which forms a disc accommodation room between the same and the half without the opening window, and the inner case is provided with an opening portion corresponding to the opening window of the half having the opening window. 
     According to a fourth aspect of the present invention, there is provided a disc cartridge, wherein the shutter member is provided with an overlapping portion which is overlapped on a peripheral portion of at least one of the opening window or opening portion. 
     According to a fifth aspect of the present invention, there is provided a disc cartridge, wherein the shutter member is provided with a convex portion which comes in contact with either one of the shutter supporting body or the half with the opening window as urges the shutter member against the other one of the shutter supporting body or the half with the opening portion by a reaction force from the contact portion. 
     According to a sixth aspect of the present invention, there is provided a disc cartridge, wherein a lock mechanism for locking the shutter member at a position where the opening window is closed is provided. 
     In the disc cartridge of the first aspect arranged as mentioned above, since the shutter member is supported between the pair of the halves, the shutter member is made to have such an arrangement which makes it difficult for the hand of a user to touch the shutter member to prevent erroneous opening and closing operations as well as for minute trash and dust to intrude so that a loss of information records due to the minute trash and dust can be prevented. 
     In the disc cartridge of the second aspect, by supporting a free end side of the shutter member with the shutter supporting body provided in the half with no opening window, the free end side is prevented from flexing and the malfunction of the shutter member to come in touch with the disc-shaped storage medium can be avoided. 
     In the disc cartridge of the third aspect, the half with no opening window and the inner case form a sealed disc accommodation room to prevent the trash and dust from intruding and the head unit can be brought to nearly the disc-shaped storage medium by the opening portion of the inner case. 
     In the disc cartridge of the fourth aspect, by shielding a clearance along the whole periphery of the opening window with an overlapping portion of the shutter member, the trash and dust can be prevented from intruding into a cartridge housing as well as the disc-shaped storage medium can be prevented from being attached with the trash and the like as well as being damaged by the trash and the like. 
     In the disc cartridge of the fifth aspect, by pressing the shutter member with the convex portion provided in the shutter member against the opening window or the opening portion, the clearance into which the trash and dust intrude is made smaller, thereby making it possible to prevent the disc-shaped storage medium from being attached with the trash and the like as well as from being damaged by the trash and the like. 
     Also, in the disc cartridge of the sixth aspect, by locking the shutter member at a position where the opening window is closed, the shutter member can be prevented from being freely opened as well as from erroneous operations of opening and closing. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 shows a first embodiment of a disc cartridge of the present invention and is a perspective view thereof with an opening window being closed by a shutter member; 
     FIG. 2 is a plan view of the disc cartridge shown in FIG. 1 with its opening window being closed by the shutter member; 
     FIG. 3 is a cross-section view taken on A—A line of the disc cartridge shown in FIG. 2; 
     FIG. 4 is a cross-section view taken on B—B line of the disc cartridge shown in FIG. 2; 
     FIG. 5 is a perspective view of the disc cartridge shown in FIG. 1 with the opening window being opened; 
     FIG. 6 is a plan view of the disc cartridge shown in FIG. 1 with the opening window being opened; 
     FIG. 7 is an exploded perspective view of the disc cartridge shown in FIG. 1; 
     FIG. 8 is a plan view of an upper half concerning the disc cartridge shown in FIG. 1; 
     FIGS. 9 A-D shows the upper half concerning the disc cartridge shown in FIG. 1, in which FIG. 9A is a side view, FIG. 9B is a cross-section view taken on E—E line of FIG. 8, FIG. 9C is a cross-section view taken of D—D line of FIG.  8  and FIG. 9D is a rear view; 
     FIG. 10 is a plan view of a lower half pertaining to the disc cartridge shown in FIG. 1; 
     FIGS. 11A-D shows the lower half concerning the disc cartridge shown in FIG. 1, in which FIG. 11A is a side view, FIG. 11B is a cross-section view taken on E—E line of FIG. 10, FIG. 11C is a cross-section view taken on F—F line of FIG.  10  and FIG. 11D is a rear view; 
     FIGS. 12A-B shows an inner case concerning the disc cartridge shown in FIG. 1, in which FIG. 12A is a plan view and FIG. 12B is a cross-section view taken on G—G line of FIG. 12A; 
     FIGS. 13A-C shows a slide member concerning the disc cartridge shown in FIG. 1, in which FIG. 13A is a front view, FIG. 13B is a side view and FIG. 13C is a plan view; 
     FIGS. 14A-B shows a lock member concerning the disc cartridge shown in FIG. 1, in which FIG. 14A is a front view and FIG. 14B is a side view; 
     FIG. 15 shows a second embodiment of the disc cartridge of the present invention and is a plan view thereof with an opening window in a state of being closed by the shutter member; and 
     FIG. 16 is a perspective view showing a conventional disc cartridge seen from a rear side. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Hereafter, an embodiment of the present invention will be explained with reference to the attached drawings. FIG. 1 to FIG. 14 show a first the embodiment of a disc cartridge according to the present invention. FIG. 1 is a perspective view showing an opening window in a state of being closed by a shutter member, FIG. 2 is a plan view of the same, FIG. 3 is a cross-section view on line A—A of FIG. 2, FIG. 4 is a cross-section view on line B—B of the same, FIG. 5 is a perspective view showing the opening window in a state of being opened, FIG. 6 is a plan view of the same, FIG. 7 is an exploded perspective view, FIG. 8 is a plan view of a first half, FIGS. 9A to  9 D are a side view of the first half, a cross-section view on line C—C, a cross-section view on line D—D and a rear side view, respectively, FIG. 10 is a plan view of a second half, FIGS. 11A to  11 D are a side view of the second half, a cross-section view on line E—E, a cross-section view on line F—F and a rear side view, respectively, FIGS. 12A and 12B are a plan view and a cross-section view on line G—G of an inner case, respectively, FIGS. 13A to  13 C are a front view, a side view and a plan view of a shutter member, respectively, FIGS. 14A to  14 B are a side view and a front view of a lock member, respectively. Also, FIG. 15 is a plan view showing a second embodiment of the disc cartridge according to the present invention. 
     A disc cartridge  11  concerning the embodiment is, as one example of the disk shaped storage medium, a disc cartridge which enables not only reproducing (read out) but also recording (write in) of an information signal by using a recordable optical disc (for example, rewritable type disc) and is comprised of a cartridge housing  12 , an optical disc  13  and a slide shutter  14 . However, the disc shaped storage medium is not limited to this embodiment, but in addition to an optical disc only for reproducing an information signal such as audio, video and the like, a magnetic disc, a magneto-optical disc and other information storage media which are made capable of both the recording and/or reproducing of information signals such as audio, video, data information of a computer and the like can be applied. 
     As FIG. 1 to FIG. 7 show, the cartridge housing  12  comprises a pair of a first half  15  and a second half  16 , a thinner case  17  showing a concrete example of a shutter supporting body accommodated inside both the halves  15 ,  16  and by superposing both the halves  15  and  16  upon each other, there is constituted a flat and thin oblong housing which is slightly long in one direction. Inside the first half  15 , there is provided a circular shaped cave-in portion  15   a , the inner case  17  is fit in the cave-in portion  15   a  and as a result, a disc accommodation room  18  for accommodating the optical disc  13  is formed in the first half  15  and the inner case  17 . 
     As FIG. 7 to FIGS. 9A-D show, the cave-in portion  15   a  of the first half  15  is displaced slightly downward in a longitudinal direction (an up to down direction in FIG. 8) and at a central portion thereof is provided an escaping concave portion  15   b  to which the hub portion of the optical disc  13  is made to correspond. At an inner surface edge on the broad width side of the longitudinal direction of the first half  15 , a notch portion  19   a  which forms one end of a guide groove  19  is formed continuously from one end to another end in a short direction which orthogonally crosses the longitudinal direction. Then, out of four corner portions surrounding the cave-in portion  15   a , at one of the corner portions on the broad width side, a concave portion  15   c  in which a lock spring  20  showing one example of the lock mechanism is accommodated is formed and also, at both corner portions on the narrow width side, concave portions  15   d  and  15   e  to aim at reducing weight and the like are formed. Then, in the vicinity of the two concave portions  15   d  and  15   c  are formed holes  21   a  and  22   a  which are matched with positioning holes  21  and  22  provided in the second half  16  to become bottom portions thereof. 
     Further, at the inner peripheral edge of the cave-in portion  15   a  of the first half  15  is formed an arc shaped inner concave portion  23   a  in which an inner frame piece of the second half  15  is fit. Then, at both the corner portions on the narrow width side of the outer peripheral edge of the first half  15  are formed L-letter shaped outer concave portions  23   b  and  23   c  in which L-letter shaped outer frame pieces of the second half  16  are fit and at one corner portion on the broad width side is formed a linear state outer concave portion  23   d  in which a linear state outer frame piece of the second half  16  is fit. At the four corner portions of the first half  15  are provided a proper number of screw holes  24  for fastening the first half  15  and second half  16  with screws. 
     An end portion of the concave portion  15   c  in the longitudinal direction on the narrow width side of the first half  15  is provided an opening portion  25   a  which opens toward the notch portion  19   a  and in the concave portion  15   c  in the vicinity of the opening portion  25   a  is projectingly provided a support pin  26 . There is provided such an arrangement that the lock spring  20  is supported by the support pin  26  and a part thereof is made capable of advancing to and retreating from the guide groove  19 . 
     The lock spring  20 , as is shown in FIG. 5, FIG.  7  and FIGS. 14A and 14B, comprises a lock main body  20   a  disposed in a V letter state, an elastic piece  20   b , and a sleeve shaft portion  20   c  provided at a connecting portion of them. The lock main body  20   a  of the lock spring  20  is comprised of an arm piece with comparatively high stiffness, which is folded to be formed in an V letter shaped and its tip end side is extended nearly in parallel with the elastic piece  20   b . To its opposite side surface to the elastic piece  20   b  is provided a nail-receiving portion  27  for locking the slide shutter  14  by engaging with a nail portion. Also, the elastic piece  20   b  is imparted with an elasticity by appropriately setting the thickness thereof thin. Then, at a tip end portion of the elastic piece  20   b  is provided with a semi-sphere shaped fulcrum portion  28  for reducing frictional resistance between the wall of the concave portion  15   c  and the elastic piece  20   b.    
     The lock spring  20  having such the arrangement, by swingably fitting the support pin  26  in the hole of the sleeve shaft portion  20   c , is accommodated in the concave portion  15   c  while the lock main body  20   a  is in a state of being made to face the opening portion  25   a  of the first half  15 . At this time, the fulcrum portion  28  of the spring tab  20   b  is made to come in contact with the inner wall surface of the concave portion  15   c  and as is shown in FIG. 2, when the lock spring  20  is in its free state, the tip end portion of the lock main body  20   a  is made to project within the guide groove  19 . At this time, the lock main body  20   a  comes in contact with a main body receiving portion  29  which is formed by providing a terraced portion  25   b  contiguous to the opening portion  25   a  of the first half  15  and as a result, the tip end portion is projected within the guide groove  19  by a predetermined amount. 
     The inner case  17  fit in the cave-in portion  15   a  of the first half  15  has an arrangement as shown in FIG.  7  and FIGS. 12A and 12B. That is, the inner case  17  is comprised of a shallow bottomed dish shaped disc and an opening hole  30  is provided on the plane portion thereof. The opening hole  30  of the inner case  17  is made an oblong hole extending in one radius direction from nearly the central portion of the plane portion to reach the vicinity of an outer peripheral edge and its central portion is formed into a circle. Then, inside the plane portion, a crescent moon shaped projected streak portion  17   a  is provided surrounding the circumference of the central side circular portion. The projected streak portion  17   a  is for supporting an inside non-storage area inside in a radius direction of the optical disc  13  where an information signal is not recorded. By supporting the non-storage area of the optical disc  13  by the projected streak portion  17   a , an information signal area in which the information signal is recorded can be prevented from coming in contact with an inner surface of the inner case  17 . 
     Further, on the opposite side of the opening hole  30  in the plane portion of the inner case  17  is provided a positioning hole  31  for positioning the inner case  17  to the second half  16 . The inner case  17 , as is shown in FIG.  3  and FIG. 4, is fit in the concave portion  15   a  by being inserted from the opening side of the plane and as a result, the disc accommodation room  18  is formed between the first half  15  and the inner case  17 . Then, the second half  16  is superposed on the inner case  17 . 
     The second half  16  is, as is shown in FIG. 7, FIG.  10  and FIGS. 11 A-D, made of a shape corresponding to the shape of the first half  15  and inside an oblong square plate body is provided an arc state inner convex portion  32   a  which fits in an inner concave portion  23   a  of the above-mentioned first half  15 , L-letter shaped outer convex portions  32   b  and  32   c  which similarly fit in outer concave portions  23   b  and  23   c  and a linear shaped outer convex portion  32   d . Further, on an inner surface of the two corners of the second half  16  are provided engaging convex portions  33   a  and  33   b  which are engaged with both end portions of the notch portion  19   a  of the first half  15 . By matching these convex portions  32   a  to  32   d  and  33   a ,  33   b  with the concave portions  23   a  to  23   d  and the notch portion  19   a , the first half  15  and the second half  16  are respectively positioned and superposed. 
     The second half  16  is provided with an opening window  35  at a position corresponding to the opening hole  30  of the inner case  17 . That is, the opening window  35  is made a long hole extending in one radius direction from nearly a central portion of the second half  16  to reach the vicinity of an outer peripheral edge thereof, and the central portion thereof is formed into a circle. The opening window  35  is slightly larger than the opening hole  30 , both being made similar in shape, and in order to position the opening hole  30  and the opening window  35  face to face, on an inner surface of the second half  16  is provided a positioning projection  16   a . By engaging the projection  16   a  with the positioning hole  31 , as is shown in FIG. 2, FIG.  6  and so on, the inner case  17  is positioned to the second half  16  and the opening window  35  and the opening hole  30  are superposed. 
     On an inner surface of the second half  16  is provided a shutter space portion  36  which is a clearance capable of slidably accommodating the slide shutter  14  between the first half  15  and the inner case  17 . The shutter space portion  36  is, as is shown in FIG.  10  and FIGS. 11A-D, set to form a predetermined clearance in the peripheral edge of the opening window  35  and opened toward the two sides, one side being in a direction along which the opening window  35  of the second half  16  extends and another side being in one of directions which is perpendicular thereto. In the shutter space portion  36 , as is shown in FIG. 1 to FIG. 6, the slide shutter  14  showing an concrete example of the shutter member is accommodated, as if sandwiched, between the first half  15  and the second half  16 . 
     The second half  16  is provided with the same number of inserting holes  37  as the screw holes  24  at positions corresponding to the screw holes of the first half  15  for screwing the second half to the first half  15 . Then, in both the corner portions on the opposite side to the side to which the opening window  35  of the second half  16  extends are provided positioning holes  21  and  22 , and by positioning both the halves  15  and  16  by respectively superposing them, both the positioning holes  21 ,  22  and positioning holes  21   a ,  22   a  are respectively matched to each other. 
     The slide shutter  14  as shown in FIG.  7  and FIGS. 13A to  13 C, comprises a shutter main body  14   a  for opening and closing the opening window  35  and a slide supporting portion  14   b  for slidably supporting the shutter main body  14   a  on the second half  16 . Then, the slide supporting portion  14   b  is provided with a lock nail  38  for locking the slide shutter  14  when the opening window  35  is in a state of being shielded by the shutter main body  14   a.    
     The shutter main body  14   a  of the slide shutter  14  is formed appropriately larger than the opening window  35  so that a mutually overlapping portion (hereafter, referred to as an overlapping portion)  40  ranging over the whole periphery of the opening window  35  of the second half  16  can be made. Therefore, an overlapping portion  41  (a portion ranging over the whole periphery of the opening portion  30 , where the shutter main body  14   a  and the opening hole  30  of the inner case  17  overlap each other) which is slightly wider in an inner side direction than the overlapping portion  40  is formed between the shutter main body  14   a  and the inner case  17 , too. By providing such double structured overlapping portions  40  and  41 , the intrusion into the disc accommodation room  18  of the trash and the like can be prevented by making it difficult for the trash and dust to pass through between the shutter main body  14   a  and the second half  16  and inner case  17 . 
     Further, the shutter main body  14   a  of the slide shutter  14  is provided with a pressuring projection  42  as a convex portion which comes in contact with the inner surface of the second half  16 . By having the pressuring projection  42  come in contact with the inner surface of the second half  16  to push the shutter main body  14   a  against the opening hole  30  side, the clearance at the overlapping portion  41  between the shutter main body  14   a  and the inner case  17  can be made as narrow as possible, thereby making it possible to more effectively prevent the trash and dust from intruding into the disc accommodation room  18 . The pressuring projection  42  of the slide shutter  14  may be projectingly provided on the inner case  17  side and in this occasion, the shutter main body  14   a  is pushed against the opening window  35  side due to the action of the pressuring projection  42  which comes in contact with the inner case  17 , thereby making it possible to obtain the same effect. 
     The slide supporting portion  14   b  of the slide shutter  14  is formed into an L-letter shape contiguous to one end in the longitudinal direction of the shutter main body  14   a . A coming off stopping tab  14   c  on the tip end side of the slide supporting portion  14   b  is, as is shown in FIG. 3, engaged with a long groove  43  provided on a rear surface on a broad width side in a longitudinal direction of the first half  15  and as a result, the slide shutter  14  is prevented from coming off. At this time, the lock nail  38  provided contiguous to the slide supporting portion  14   b  is inserted into the notch portion  19   a  of the first half  15 , and the guide groove  19  is formed by the notch portion  19   a  and the second half  16 . The lock nail  38  is detachably engaged with the nail receiving portion  27  of the lock spring  20 . 
     Also, as for the optical disc  13  accommodated in the disc accommodation disc  18  of the cartridge housing  12  having the above-mentioned arrangement, for example, a phase change type optical disc can be applied. The phase change type optical disc changes a phase of a film from a crystalline state to an amorphous state by adding heat to a recording film of a GeTeSb system and carries out recording of an information signal by utilizing the difference in the reflection coefficient of light due to a change in phase as well as reproduces the information signal by detecting the same by the optical head. In the central portion of the optical disc  13  is, as shown in FIG.  3  and FIG. 4, provided a hub portion  13   a  which swells to one surface side, and inside the hole of the hub portion  13   a  is fit in and fixed a hub plate  45  formed of magnetic material. 
     By fitting the turntable of the disc recording and reproducing apparatus in the hub  13   a  and by having a magnet built in the turntable adsorb and fix the hub plate  45 , the optical disk  13  is driven into rotation by a spindle motor. On the outside in the radius direction of the hub portion  13   a  of the optical disk  13  the above-mentioned signal storage area is set and the optical pick-up device of the disc recording and reproducing apparatus is made to face the signal storage area thorough the above-mentioned opening window  35  and the opening hole  30 . 
     As for the materials of the above-mentioned first and second halves  15 ,  16  and the lock spring  20 , for example, an ABS resin (acrylonitrile, butadiene, styrene resin) and other synthetic resin are suitable, but aluminum alloy and other metals can be used. Also, as for the materials of the slide shutter  14  and the inner case  17 , metals such as stainless steel and the like are suitable, but the ABS resin and other plastic can be used. 
     Meanwhile, though not shown graphically, by providing an erroneous erasure protection mechanism in the cartridge housing  12 , for example, by having an erroneous erasure protection hole structured to be capable of opening and closing by a manipulating knob, there can be provided an arrangement to select a state where writing to the optical disk  13  is possible and a state where writing thereto is made impossible. 
     The disc cartridge  11  with such the arrangement is, for example, can be simply assembled in the following way. First of all, after the swelled portion side of the hub  13   a  of the optical disc  13  is inserted in the concave portion  15   a  of the first half  15 , the opening side of the inner case  17  is fit in the concave portion  15   a . At that time, the inner case  17  is fit by aligning the direction in which the opening hole  30  extends with the longitudinal direction of the first half  15 . 
     Next, the lock spring  20  is set in the concave portion  15   c  of the first half  15 . The lock spring  20  has the hole of the sleeve shaft portion fit the support pin  26  of the concave portion  15   c  as well as the tip end of springy tab  20   b  come in contact with the inner wall surface of the concave portion  15   c , thereby having the tip end portion of the lock main body  20   a  project within the guide groove  19 . 
     Next, the slide shutter  14  is fit to the first half  15 . In this case, the slide supporting portion  14   b  of the slide shutter  14  is made to face the broad width side in the longitudinal direction of the first half  15 , and the coming off stopping piece  14   c  is made to engage with the long groove  43  as well as the lock nail  38  is made to engage with the guide groove  19  in a way that the shutter main body  14   a  closes the opening hole  30 . 
     Next, the second half  16  is made to face on the slide shutter  14  and the inner convex portion  32   a  provided on the inner surface thereof is positioned to the inner concave portion  23   a  of the first half  15  and the outer convex portions  32   b  to  32   d  provided in the peripheral portion thereof are positioned to the outer concave portions  23   b  to  23   d . Consequently, the engaging convex portions  33   a  and  33   b  provided in both the corner portions on the broad width side in the longitudinal direction of the second half  16  are simultaneously positioned. Concurrently, as mentioned above, by fitting the inner case  17  in a predetermined posture, the positioning projection  16   a  provided in the second half  16  is positioned to the positioning hole  31  of the inner case  17 . 
     Then, by pushing the second half  16  against the first half  15  side to superpose both the halves  15  and  16 , the cartridge housing  12  is assembled with the slide shutter  14  in a state of being accommodated in the shutter space portion  36  of the second half  16 . Thereafter, by inserting securing screws in the inserting holes  37  of the second half  16  to have the tip end thread portions thereof engage with screw holes  24  of the first half  15 , both the halves  15  and  16  are integrally united through a plurality of securing screws and the assembly work of the disk cartridge housing  11  is completed. 
     The disc cartridge  11  manufactured in this manner can be used as a recording medium of a personal computer capable of using a disc shaped storage medium such as an optical disc and the like, or a digital still camera, a digital video camera and other disc recording and/or reproducing apparatus. 
     Next, a case where the disc cartridge  11  is used for, for example, the disc recording and/or reproducing apparatus of a personal computer or the like will be explained. The disc cartridge  11  is inserted into the cartridge inserting mouth of the disc recording and/or reproducing apparatus from the left side shown by an arrow mark in FIG.  2 . 
     Consequently, a manipulating pin of a shutter opening and closing mechanism, not shown graphically, provided in the disc recording and/or reproducing apparatus enters in the guide groove  19  of the disc cartridge  11  and a tip end portion thereof comes in contact with the lock main body  20   a  of the lock spring  20  projecting in the guide groove  19 . When the disc cartridge  11  is further inserted, as is shown in FIG. 6, the lock main body  20   a  is pushed in the opening portion  25   a  against the spring force of the springy piece  20   b  of the lock spring  20 . 
     As a result, the lock nail  38  comes off the nail receiving portion  27  of the lock main body  20   a , and the locking of the lock nail  38  by the nail receiving portion  27  is released, with the slide shutter  14  becoming a state of being able to move freely. Then, by further inserting the disc cartridge  11 , the slide shutter  14 , pushed by the manipulating pin, moves to change from a state shown in FIG.  1  and FIG. 2 to a state shown in FIG.  5  and FIG.  5 . As a result, the opening hole  30  is opened and the hub portion  13   a  of the optical disc  13  and part of the information storage area are partially exposed through the opening window  35  and the opening portion  30 . 
     Then, by inserting the turntable through the opening window  35  and the opening portion  30  to be fit to the hub  13   a  and securely fixed by the magnetic force, the optical disc  13  integrates with the turntable and becomes capable of rotating. Then, by inserting the optical head of the optical pick-up device through the opening window  35  and the opening portion  30  to face the information storage area of the optical disc  13 , writing (recording) to and reading out (reproducing) of information signals from the information storage area becomes possible. 
     Also, an ejecting operation of the disc cartridge  11  can be carried out by reversing the above-mentioned inserting operation. That is, to take out the disc cartridge  11 , when the disc cartridge  11  is moved in the right direction in FIG. 6, the slide shutter  14  is engaged with the manipulating pin and moves in the left direction so as to close the opening hole  30 . 
     Then, the slide shutter  14  moves a predetermined distance and as is shown in FIG. 2, when the opening hole  30  is completely closed, the lock nail  38  jumps over the tip end portion of the lock main body  20   a  of the lock spring  20  to be engaged with the nail receiving portion  27 . As a result, the slide shutter  14  is locked by the lock spring  20  and becomes a state of being completely closed. 
     In this case, the slide shutter  14  is supported, as if sandwiched between the first half  15  and the second half  16  and as shown in FIG.  3  and FIG. 4, the surfaces of the shutter main body  14   a  and the slide supporting portion  14   b  are so arranged to be on the inner side of the surface of the second half  16 . For that reason, since a user can not simply touch the surfaces of shutter main body  14   a  as well as the slide supporting portion  14   b , fears that a user accidentally opens the slide shutter  14  can be diminished, thereby making it possible to prevent the intrusion of the trash and dust due to such an erroneous opening operation. 
     Also, in a state where the opening hole  30  and the opening window  35  are shielded, since there is provided an arrangement such that the overlapping portion  41  is provided between the slide shutter  14  and the opening hole  30  of the inner case  17  and the overlapping portion  40  is provided between the slide shutter  14  and the opening window  35  of the second half  16 , these overlapping portions  40  and  41  seal the circumference of the opening portion to restrict to the minimum the entering of the trash and dust into the disc accommodation room  18 , thereby making it possible to effectively prevent the trash from intruding. 
     A disc cartridge  50  shown in FIG. 15 is one in which the lock mechanism of the above-mentioned embodiment is disused. The disc cartridge  50  is not provided with a lock mechanism like a 3.5 inch floppy, disc and is so arranged as to always close the opening window  35  by a return spring, not shown graphically, built in the cartridge housing  12 . However, there can be an arrangement in which the return spring is not used. Also, an inserting direction of the disc cartridge  50  toward the cartridge inserting mouth is a direction which crosses the moving direction of the slide shutter  14  and that is, is set in the upper part in FIG.  15 . However, needless to say, the inserting direction of the disc cartridge  50  can be set in the same direction as the moving direction of the shutter slide  14 . 
     The present invention is not limited to the above-mentioned embodiment. For example, in the above-mentioned embodiment, the example in which the use of the optical disc as the disc shaped storage medium capable of not only reproducing but also recording has been explained, but it is possible to use not only a reproduction only optical disc but also a magnetic disc, a magneto-optical disc and other disc shaped storage medium. Further, in the above-mentioned embodiment, an example in which a circular shaped lid body covering the whole of the concave-in portion  15   a  is used as the shutter supporting body is explained, but it is also possible to use a bridge shaped supporting body which supports only the tip end portion side of the shutter main body  14   a  of the slide shutter  14 . In this case, the above-mentioned overlapping portion becomes only one site formed between the slide shutter  14  and the second half  16 . 
     Also, in the above-mentioned embodiment, an explanation has been made of an example in which the opening window  35  is provided in only the second half  16 , but it is possible to provide an opening window at a corresponding position of the first half  15  so that the upper and lower opening windows are simultaneously closed by the slide shutter  14 . In this case, a damper to support a disc shaped storage media by sandwiching it with a turn table is provided in the disc recording and/or reproducing apparatus side so that at a time of chucking, the clamper enters into the opening window to be made capable of supporting an optical disc by sandwiching it together with the turn table. 
     Further, as a method of pressing the disc shaped storage medium to the turn table, an explanation has been made of an example in which a magnet adsorbing system for adsorbing a hub plate to a turn table on the spindle motor side by a magnetic force of a magnet is applied, but various kinds of adsorbing systems such as, for example, a spring adsorbing system which uses a spring, an own weight system by the own weight of an information recording disc and the like can be applied. In this manner, the present invention can be variably changed without departing from the gist of the present invention. 
     As explained up to now, according to the disc cartridge as stated in the first aspect of the present invention, since there is provided such an arrangement that the shutter member is interposed between a pair of halves and supported, as if sandwiched, by both the halves by making it difficult for the user to touch the shutter member, the erroneous opening and closing apertures by the user can be prevented as well as by making it difficult for the minute trash and dust to intrude, it is possible to obtain an effect in providing the disc cartridge capable of preventing the loss of the information record due to minute trash and dust. 
     According to the disc cartridge as stated in the second aspect of the present invention, since there is provided an arrangement such that the free end side of the shutter member is supported by the shutter supporting body provided in the half without the opening window, it is possible to prevent the free end side from flexing, as well as preventing an inconvenience that the shutter member comes in contact with the disc shaped storage medium. 
     According to the disc cartridge as stated in the third aspect of the present invention, by forming the disc accommodation room sealed by the half without the opening window and the inner case, it is possible to surely prevent the trash and dust from intruding as well as to obtain an effect that the head portion can be brought near the disc shaped storage medium by the opening hole of the inner case. 
     According to the disc cartridge as stated in the fourth aspect of the present invention, since there is provided an arrangement that the clearance along the whole periphery of the opening window is shielded by the overlapping portion of the shutter member, it is possible to surely prevent the trash and dust from intruding in the cartridge housing as well as to prevent the trash and the like from attaching the disc cartridge shape storage medium and the disc shaped storage medium from being damaged by the trash and the like. 
     According to the disc cartridge as stated in the fifth aspect of the present invention, since there is provided an arrangement that the shutter member is pushed against the opening window or the opening portion by the convex portion provided in the shutter member, it is possible to obtain effects in making the clearance small for the trash and dust to enter into as well as preventing the trash and the like from attaching the disc cartridge shape storage medium and the disc-shaped storage medium from being damaged by the trash and the like. 
     Also, according to the disc cartridge as stated in the sixth aspect of the present invention, since there is provided an arrangement that the shutter member by the lock mechanism is locked at a position where the opening window is shielded, it is possible to obtain an effect in preventing the shutter member from being freely opened as well as preventing the erroneous opening and closing operation. 
     Having described preferred embodiments of the present invention with reference to the accompanying drawings, it is to be understood that the present invention is not limited to the above-mentioned embodiments and that various changes and modifications can be effected therein by one skilled in the art without departing from the spirit or scope of the present invention as defined in the appended claims.