Abstract:
There is provided a disk apparatus having a construction in which a reproducing unit is accommodated inside an enclosed space, whereby an optical head is protected from external dust. The optical head reads information recorded on a disk. Component parts of the disk apparatus are accommodated inside a case. The optical head is provided on a chassis formed in a box-like shape, the chassis having walls with ends which have contacting surfaces which come in contact with the case. A circuit board assembly which receives circuit processing information from the optical head is positioned outside the chassis. The chassis and the case together form an enclosed space, the optical head being accommodated inside the enclosed space.

Description:
This application is a divisional of U.S. patent application Ser. No. 08/801,100 filed Feb. 14, 1997 now abandoned which is a continuation of U.S. patent application Ser. No. 08/363,387 filed Dec. 23, 1994 now abandoned. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention generally relates to a disk apparatus, and more particularly to a disk apparatus which has a dust proof construction ensuring an effective release of heat, a reduced thickness and easy to assemble. 
     FIG. 1 shows a conventional optical disk apparatus  10 . 
     The optical disk apparatus  10  comprises a bottom plate  11  on which a circuit board assembly  12  and a reproducing unit  13  are mounted. A disk tray  14  is movable in directions indicated by arrows A 1  and A 2 . A case  15  having a top plate  15   a  and side plates  15   b  covers the reproducing unit  13  having an optical head  22  (see FIG. 2) and the circuit board assembly  12 , and is mounted on the bottom plate  11  by means of screws. Accordingly, the reproducing unit  13  and the circuit board assembly  12  are enclosed in the apparatus, and thus the optical head  22  is protected from external dust. 
     In the above-mentioned optical disk apparatus  10 , since the circuit board assembly  12  is enclosed in the apparatus, when the apparatus is used, and in particular, uses continuously for a long time, the temperature inside the apparatus considerably increases due to heating of the circuit board assembly  12 . 
     In order to reduce the temperature increase, hot air inside the optical disk apparatus  10  is released to the outside, and external cool air is introduced into the apparatus. However, in this case, dust may enter inside the apparatus together with the cool air introduced inside the apparatus, and thus there is a problem in that the dust adheres onto the optical head. 
     FIG. 2 is a schematical perspective view of the conventional optical disk apparatus  10 . 
     In FIG. 2, a mechanical unit  25  comprises a base  19  pivotally provided on a chassis  17  by being supported by a shaft  18  on one end thereof, a turn table driving motor  20 , a turn table  21  and the optical head  22  being mounted on a base  19 . 
     Reference numeral  23  indicates a gate-type disk clamper supporting member which is mounted on the chassis  17  to be bridged over the mechanical unit  25 . 
     A stem  16   a  of a disk clamper  16  is fitted in a through hole  23   a  of the supporting member  23 , as shown in FIG. 3A, and is attached to the supporting member  23  by a screw  24  serving as a stopper. 
     A disk  30  is loaded in the optical disk apparatus  10  in the manner as explained below. 
     In an initial state, the mechanical unit  25  is inclined as shown in FIG. 3A, and thus the turn table  21  is located at a lower position. The disk  30  is placed on a tray  14 , and then is carried into the optical disk apparatus  10 . When the disk  30  is carried into the apparatus, a lifting mechanism  26  starts to operate to rotate the mechanical unit  25  in a direction indicated by an arrow A, the mechanical unit  25  being rotated to be horizontally positioned as indicated in FIG.  3 B. 
     Accordingly, as shown in FIG. 3B, the disk  30  is supported by the turn table  21  in a state where the disk  30  is lifted up from the tray  14 . Additionally, the disk clamper  16  is magnetically attracted by the turn table  21 , and thus the disk  30  is clamped. After the disk  30  is clamped, the turn table  21  is rotated by the motor  20 , and then information on the disk  30  is reproduced by means of the optical head  22 . 
     In the above-mentioned disk loading mechanism, since the disk clamper supporting member  23  is located above the disk clamper  16 , and since the top plate  15   a  of the case  15  covers the supporting member  23 , there is a problem in that a height h 10  (refer to FIG. 3A) of the optical disk apparatus  10  is relatively great, thus preventing the thickness of the apparatus from being reduced. 
     FIG. 4 is a schematic view showing how the optical head  22  is connected to the reproducing unit  13  of the optical disk apparatus  10 . In the optical disk apparatus  10 , the reproducing unit  13  and the circuit board assembly  12  are arranged on the chassis  17  in a state where they are piled on top of each other. The reproducing unit  13  is provided with the turn table  21  and the optical head  22  movable in directions indicated by arrows X 1  and X 2 . 
     A tape-like flexible printed circuit (FPC)  27  extends from the optical head  22 . The FPC  27  extends through an opening  17   a  formed in the chassis  17 , and is connected to an FPC connector  28  mounted on the circuit board assembly  12  located under the chassis  17 . 
     An operation for connecting the FPC  27  to the FPC connector  28  is carried out by using a jig  29  as shown in FIG.  5 . One end of the FPC  27 , the other end of which is connected to the optical head  22 , is drawn out to extend to the lower side of the chassis  17  by passing it through the opening  17   a  while the reproducing unit  13  is held in an oblique state by means of the jig  29 . The one end of the FPC  27  is then inserted into the FPC connector  28 , as shown by an arrow B in FIG.  5 . 
     Since the operation for connecting the FPC  27  to the FPC connector  28  must be performed in a relatively narrow space, there is a problem in that the operation is inconvenient and takes a long time. Additionally, since the FPC  27  is being made as short as possible from the view point of cost reduction, there is a possibility of the FPC  27  being drawn out accidentally by a strong force, thereby damaging the optical head  22 . 
     SUMMARY OF THE INVENTION 
     It is a general object of the present invention to provide an improved and useful disk apparatus in which the above-mentioned problems are eliminated. 
     A more specific object of the present invention is to provide a disk apparatus having a construction in which only a reproducing unit is accommodated in an enclosed space, and thus an optical head is protected from external dust. 
     Another object of the present invention is to provide a disk apparatus having a thickness which is reduced by eliminating the use of a supporting member for a disk clamper. 
     Another object of the present invention is to provide a disk apparatus in which an operation for connecting the optical head to a circuit board assembly is easily performed by having a connector on a chassis of a reproducing unit. 
     In order to achieve the above-mentioned objects, there is provided according to one aspect of the present invention a disk apparatus having a head for reading information recorded on a disk, the disk apparatus comprising: 
     a case accommodating component parts of said disk apparatus; 
     a chassis, formed substantially in a box-like shape, having a chassis body on which the head is mounted, the chassis body having walls on sides thereof, each of the walls having a contacting surface on an upper end thereof which contacting surface comes into substantial contact with the case; and 
     a circuit board assembly positioned inside the case and outside the chassis, a circuit which processes information input from the head being provided on the circuit board assembly, 
     wherein the chassis together with the case form an enclosed space, and the head is accommodated inside the enclosed space so as to be protected from external dust. 
     According to another aspect of the present invention, there is provided a disk apparatus in which a disk is lifted by a turn table moving upward, and a clamper positioned above the turn table clamps the disk on the turn table, the disk apparatus comprising: 
     a case having a top plate which covers the turn table; and 
     a clamper mounting portion formed on the top plate, the clamper being mounted on the clamper mounting portion. 
     According to another aspect of the present invention, there is provided a disk apparatus having a mechanism assembly having a chassis on which a head for reproducing information recorded on a disk is provided and a circuit board assembly having a circuit which processes the information received from the head, the circuit board assembly being positioned under the mechanism assembly, the disk apparatus comprising: 
     a flexible connecting wire, extended from the head, for transmitting information from the disk; 
     a first connector, provided on the chassis, having connector pins protruding downward from the chassis, one end of the flexible connecting wire being connected to the first connector provided on the chassis; and 
     a second connector located at a position corresponding to that of the connector pins of the first connector, 
     wherein the first connector is automatically connected to the second connector when the circuit board assembly and the chassis are assembled together. 
     Other objects, features and advantages of the present invention will become more apparent from the following detailed description when read in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a conventional disk apparatus; 
     FIG. 2 is a perspective view for explaining a disk clamping mechanism in the disk apparatus shown in FIG. 1; 
     FIGS. 3A and 3B are illustrations for explaining an operation of the clamping mechanism shown in FIG. 2; 
     FIG. 4 is an illustration for explaining how an optical head is connected to a circuit board assembly in the conventional disk apparatus; 
     FIG. 5 is an illustration for explaining an operation for connecting the optical head with the circuit board assembly shown in FIG. 4; 
     FIG. 6 is an exploded perspective view of a first embodiment of a CD-ROM apparatus according to the present invention; 
     FIG. 7 is a cross-sectional view taken along a line VII—VII of FIG. 6; 
     FIG. 8 is a cross-sectional view taken along a line VIII—VIII of FIG. 6; 
     FIG. 9 is a perspective view for explaining a variation of an enclosing structure shown in FIG. 6; 
     FIG. 10 is an illustration of the CD-ROM apparatus of FIG. 6, showing a state before a disk is loaded; 
     FIG. 11 is an illustration of the CD-ROM apparatus of FIG. 6, showing a state after a disk is loaded; 
     FIG. 12 is a perspective view of an essential part of the CD-ROM apparatus of FIG. 6; 
     FIG. 13 is a plan view of the inside of the CD-ROM apparatus of FIG. 6; 
     FIG. 14 is an illustration showing how the optical is connected to the circuit board assembly of CD-ROM apparatus of FIG. 6; 
     FIG. 15 is an illustration for explaining an assembling operation of a relay circuit board shown in FIG. 6; and 
     FIG. 16 is an illustration for explaining an operation for assembling together the reproducing unit and the circuit board assembly shown in FIG.  6 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 6 is a perspective view of an embodiment of a CD-ROM apparatus  80  according to the present invention. FIG. 7 is a cross-sectional view of the assembled CD-ROM apparatus  80  taken along a line VII—VII of FIG. 6, and FIG. 8 is a cross-sectional view taken along a line VIII—VIII of FIG.  6 . 
     In the CD-ROM apparatus  80 , mechanism assembly  31  and a circuit board assembly  32  ar assembled together by means of screws  33  in a state where the mechanism assembly  31  is placed above the circuit board assembly  32 . A case  34  covers the mechanism assembly  31 , and is attached thereto by means of screws  35 . A bottom plate  36  covers the underside of the circuit board assembly  32 , and is attached to thereto by means of screws  37 . A reference numeral  38  indicates a disk tray, and  39  a front bezel. 
     A chassis  40  having substantially a box-like shape comprises a chassis body  40   a  having a generally plate-like shape and walls  40   b ,  40   c  and  40   c . The wall  40   b  is on the left side of the chassis body  40   a  when viewed from the front bezel  39 . The wall  40   c  is on the right side of the chassis body  40   a  when viewing from the front bezel  39 . The wall  40   d  is raised on the side of the chassis body  40   a  opposite to the front bezel  39 . The walls  40   a ,  40   b  and  40   c  are connected to form a channel-like shape when viewed from above. Additionally, top surfaces  40   b - 1 ,  40   c - 1 ,  40   d - 1  of the walls  40   b ,  40   c ,  40   d  are positioned in the same plane. 
     A wall is not provided on a front bezel side of the chassis body  40   a , and thus an opening  41  is formed. End surfaces  40   a - 2 ,  40   b - 2 ,  40   c - 2  are formed on a front bezel side of each of the chassis body  40   a  and walls  40   b  and  40   c , respectively. 
     An optical head  42 , an optical head moving mechanism  43 , a turn table  44 , a turn table driving motor and tray moving mechanism  46  are provided in the chassis  40 . As shown in FIGS. 7 and 8, a disk  51  is rotated by means of the motor  45  in an enclosed space  60  in a state where the disk  51  is placed on the turn table  44 . Information recorded on the disk  51  is reproduced by means of the optical head  42 . 
     The case  34  comprises a top plate  34   a , left and right side plates  34   b ,  34   c , a back plate  34   d  and a front plate  34   e . An opening  34   e - 1  through which the tray  38  is moved is formed on the front plate  34   e . A sponge tape  47  having a shape corresponding to the walls  40   b ,  40   c ,  40   d  of the chassis  40  is attached on an inner surface of the top plate  34   a . Additionally, a frame  48  made of a sponge is attached on an inner surface of the front plate  34   e  so that the frame  48  encircles the opening  34   e - 1 . 
     The chassis  40  and the case  34  are assembled together, as shown in FIGS. 7 and 8, in a state where the sponge tape  47  is sandwiched between the top plate  34   a  of the case  34  and the surfaces  40   b - 1 ,  40   c - 1 ,  40   d - 1  of the walls  40   b ,  40   c ,  40   d , respectively, and in a state where the sponge frame  48  is sandwiched between the front plate  34   e  and the end surfaces  40   a - 2 ,  40   b - 2 ,  40   c - 2  of the chassis body  40   a  and walls  40   b ,  40   c.    
     As mentioned above, the top plate  34   a  covers the upper side of the chassis body  40   a . Additionally, an opening  39   a  of the front bezel  39  is closed by a front panel  38   a  of the tray  38 . 
     Accordingly, the space  60  in the box-like chassis  40  is enclosed to have a dust proof construction, and thus the optical head  42  provided in the chassis  40  is protected from dust. That is, the sponge tape  47  and the sponge frame  48  serve as sealing members, and therefore a highly effective dust protection is obtained. 
     Additionally, in a state where the tray  38  is retracted in the CD-ROM apparatus  80 , as shown in FIG. 7, the front panel  38   a  of the tray  38  presses the front plate  34   e  with a sponge frame  49  therebetween. 
     This seals the opening  34   e - 1  very well, and thus further effective protection of the chassis against dust is obtained. 
     An electrical connection of the mechanism assembly  31  to the circuit board assembly  32  is provided through a connector  92  protrudingly and downwardly mounted on the chassis body  40   a . A portion of the chassis body  40   a  around the connector  92  is closed by a mounting board of the connector  92 . Thus, the space  60  in the chassis  40  is further sealed. 
     The inventor of the present application investigated the amount of dust adhered to the optical head by observing a degradation of a reproducing level of each of the CD-ROM apparatus  80  according to the present embodiment and the conventional optical disk apparatus  10  shown in FIG. 1 by placing them in a dusty area. The result of the investigation showed that the CD-ROM apparatus  80  according to the present embodiment had a dust protection level 4 to 5 times higher than that of the conventional optical disk apparatus  10 . 
     A description will now be given, with reference to FIG. 8, of how heat is released from the circuit board assembly  32 . 
     The circuit board assembly  32  is positioned under the chassis  40  at a slight distant therefrom, and accommodated inside a space  62  formed by the case  34  and the bottom plate  36 . 
     The case  34  has a plurality of small ventilation holes  34   f  along a border between the top plate  34   a  and the side plates  34   b ,  34   c . Additionally, the case  34  has a plurality of ventilation holes  34   g . Accordingly, the space  62  is provided with many ventilating holes. 
     Therefore, hot air produced by heat generated in the circuit board assembly  32  passed through the ventilation holes  34   f ,  34   g  to be released outside the CD-ROM apparatus  80 , and thereby releasing of the heat from the circuit board assembly  32  is performed. 
     As a result, the mechanism assembly  31  is not affected by heat, which condition results in a continuous normal operation being possible even if the CD-ROM apparatus  80  is operated for a long time so that a lot of heat generated by the circuit board assembly  32 . 
     FIG. 9 shows a variation of the above-mentioned embodiment. 
     A CD-ROM apparatus  80 A shown in FIG. 9 has a case  34 A. A top plate  34 A a  of the case  34 A has an elongated protrusions  70  on one side thereof and an elongated protrusion  71  on another side thereof in portions corresponding to the position where the sponge tape  47  is provided in FIG. 6, a grooves  72  being formed between the two protrusions  70  and  71 . In this construction, an upper end of each of the walls  40   b ,  40   c ,  40   d  of the chassis  40  fits in the groove  71 , and thus a seal between the top plate  34 A a  and each of the walls  40   b ,  40   c ,  40   d  is provided. Accordingly, in this variation, the sponge tape  47  shown in FIG. 6 is not provided. 
     FIGS. 10 and 11 are illustrations for explaining a disk loading operation of the CD-ROM apparatus  80 . 
     A mechanism unit  57  comprises the turn table  44 , the turn table driving motor  45 , the optical head  42  and the optical head moving mechanism  43  mounted on a base  52 . 
     One side of the base  52  is supported on the chassis body  40   a  via an insulator  55 , and thus the base  52  is rotatable in a direction indicated by an arrow A of FIG. 10 about the insulator  55 . A clamper mounting portion  65  is formed as a recess in the center of the top plate  34   a  of the case  34 . 
     A stem  66   a  of a clamper  66  loosely fits in a hole  65   a  formed in a clamper mounting portion  65 . A screw  67  is screwed from the outside of the case into a threaded hole of the stem  66   a , and thus the clamper  66  is attached on the top plate  34   a  of the case  34 . A screw head  67   a  of the screw  67  is accommodated within the clamper mounting portion  65 . 
     A description will now be given of a disk loading operation. 
     In an initial state, the mechanism unit  57  is inclined as shown in FIG. 10, and thus the turn table  44  is at a lower position. A user places the disk  51  on the tray  38 , and then press a loading button not shown in the figure. The tray moving mechanism  46  then starts to operate to retract the tray into the CD-ROM apparatus  80 , and therefore the disk  51  is carried into the CD-ROM apparatus  80 . 
     The mechanism unit  57  is then rotated to a horizontal position indicated in FIG. 11 by the mechanism  46  in the direction indicated by the arrow A of FIG.  10 . At this time, the turn table  44  lifts the disk  51  and the disk  51  lifts the clamper  66 . The clamper  66  is magnetically attracted by the turn table  44 . Accordingly, the disk  51  is supported on the turn table  44  in a state where the disk  51  is slightly apart from the tray  38 , and is clamped by the clamper  66  on the turn table  44 . 
     The disk  51  is loaded in the manner mentioned above, and then the turn table  44  is rotated by means of the motor  45 , and information on the disk  51  is reproduced by means of the optical head  42 . 
     When an unloading operation is performed, each of the mechanisms of the CD-ROM apparatus  80  is operated in the reverse order so that the disk  51  is unclamped and ejected by the tray  38 . 
     A comparison will now be made of a height of the CD-ROM apparatus  80  with that of the conventional optical disk apparatus shown in FIG.  3 A. Referring to the FIGS. 11 and 3A, the bases  36  and  11  are positioned at the same level H 1 . In the conventional optical disk apparatus  10 , the clamper supporting member  23  is located between the clamper  16  and the top plate  15   a  of the case  15 . On the other hand, in the CD-ROM apparatus  80  according to the present invention, no member is located between the clasper  66  and the top plate  34   a  of the case  34 . 
     Assuming that a distance in a height direction between the clamper  16  and the top plate  15   a  of the case  15  of the conventional optical disk apparatus  10  is h 1 , a distance h 2  between the clamper  66  and the top plate  34   a  of the case  34  of the CD-ROM apparatus  80  according to the present invention is less than the distance h 1  by a thickness t of the clamper supporting member  23 . 
     Accordingly, a height h 20  (see FIG. 10) of the CD-ROM apparatus  80  is less than a height h 10  of the conventional optical disk apparatus  10 , and thus the CD-ROM apparatus  80  is thinner than the conventional optical disk apparatus. 
     It should be noted that the appearance of the apparatus according to the present invention is not spoiled because the clamper mounting portion  65  can be hidden by a label such as a caution label being put on the clamper mounting portion  65 . 
     A description will now be given of how the optical head  42  is electrically connected to the circuit board assembly  32  in the CD-ROM apparatus  80 . FIG. 12 is a perspective view of an essential part of the CD-ROM apparatus  80 . FIG. 13 is a plane view of inside of the CD-ROM apparatus  80 . 
     In FIGS. 12 and 13, a reference numeral  90  indicates a relay circuit board. The relay circuit board  90  has an easy to handle size 2 cm×5 cm, and has on a bottom surface an FPC connector  91  and a male connector  92  (first connector). In the male connector  92 , pins  92   a  are provided to extend downwardly from the bottom surface of the relay circuit board. A short solder terminal  100  is formed on a top surface of the relay circuit board as shown in FIG.  13 . 
     A tape-like flexible printed circuit (FPC)  95  is drawn out from the optical head  42  in a direction indicated by an arrow X 1 , and then extended under the optical head  42  in an opposite direction indicated by an arrow X 2  by being gently looped. An end of the FPC  95  is formed in an L-shape and has a inserting portion  95   a  in which terminals  96  are arranged. 
     A relay circuit board mounting portion  97  is provided in the chassis  40 . A rectangular opening  98  formed in the mounting portion  97  corresponds to the shape of the male connector  92 . 
     A female connector  99  (second connector) is mounted on a main circuit board  32   a  of the circuit board assembly  32  at a position corresponding to the male connector  92  when the mechanism assembly  31  and the circuit board assembly  32  are assembled together. The female connector  99  has terminals  99   a  which receive the pins  92   a  of the male connector  92 . 
     Each of the above mentioned parts are connected as shown in FIG.  14 . That is, first, an end of the FPC  95  is connected to the FPC connector  91 . The relay circuit board  90  is then mounted on the relay circuit board mounting portion  97  of the chassis  40  by means of screws  93 . In this state, the male connector  92  is fitted in the opening  98 , so that the pins  92   a  of the male connector  92  are made to protrude downward from the chassis  40 . The circuit board assembly  32  is fixed to a bottom side of the chassis  40  by means of screws  33 . The pins  92   a  entered inside the female connector  99 , to be connected to the terminal  99   a . In this state, the male connector  92  is connected to the female connector  99 . 
     Accordingly, the optical head  42  is electrically connected to the main circuit board  32   a  via the FPC  95 , the FPC connector  91 , the relay circuit board  90 , the male connector  92  and the female connector  99 , in that order. 
     A description will now be given, with reference to FIGS. 15 and 16, of an assembling operation of the above-mentioned parts. 
     First, as shown in FIG. 15, the inserting portion  95   a  provided on an end of the FPC  95  is inserted into the FPC connector mounted on the relay circuit board  90 . Since the relay circuit board  90  is small in size, the above-mentioned operation can be easily performed. The relay circuit board  90  is positioned on the relay circuit board mounting portion  97  so that the male connector  92  fits in the opening  98 , as shown in FIG. 15, and then the relay mounting board  90  is fixed to the chassis  40  by means of the screws  93 . 
     Accordingly, after the mechanism assembly  31  is assembled as described above, it is no longer necessary to handle the FPC  95 . Thus, accidental drawing out of the FPC  95  is prevented. It should be noted that the relay circuit board  90  and the FPC  95  are connected to each other before the mechanism assembly is assembled. 
     Lastly, the mechanism assembly  31  and the circuit board assembly  32  are placed opposite to each other, and then fixed to each other by means of the screws  33 . At this time, the male connector  92  is automatically connected to the female connector  99 . 
     As is apparent from the above description, the operation for connecting the optical head  42  to the main circuit board  32   a  can be performed in a condition in which there is no possibility that the FPC  95  can be drawn out by an excessive force, no special jig is used, and a portion of the operation can be automatically performed in a process in which the mechanism assembly  31  and the circuit board assembly  32  are mechanically connected to each other. 
     A description will now be given of a short solder  101  shown in FIG.  13 . 
     The short solder  101  is provided in the apparatus to protect a semiconductor laser in the optical head  42  from static electricity damage which may occur during a process for assembling the CD-ROM apparatus  80 . The short solder  101  is removed after the optical head  42  is connected to the main circuit board  32   a.    
     In the CD-ROM apparatus  80 , since a terminal  100  for the short solder  101  is formed on a top surface of the relay circuit board  90 , the short solder  101  is applied, as indicated by a chain line in FIG. 13, on the top surface of the relay circuit board  90 . Since the top surface of the relay circuit board  90  faces upward, a solder iron can easily access the short solder, and thus an operation to remove the short solder can be easily performed. 
     It should be noted that the present invention is not limited to the CD-ROM apparatus, and may be applied to apparatuses handling a compact disk (CD), a magneto-optical disk and a magnetic disk. 
     The present invention is not limited to the specifically disclosed embodiments, and variations and modification may be made without departing from the scope of the present invention.