Abstract:
A pickup damper is provided. The pickup damper is configured to be installed adjacent to a plurality of guide shafts installed on opposite sides of an opening of a base chassis, configured to collide with a pickup and relieve shock via at least three steps in response to an external shock being applied, and configured to prevent the pickup from colliding with the guide shafts to protect the pickup.

Description:
CROSS-REFERENCE TO RELATED PATENT APPLICATION 
       [0001]    This application claims the benefit under 35 U.S.C. §119(a) of Korean Patent Application No. 10-2011-0076147 filed on Jul. 29, 2011, in the Korean Intellectual Property Office, the entire disclosure of which is incorporated herein by reference for all purposes. 
       BACKGROUND 
       [0002]    1. Field 
         [0003]    The following description relates to a pickup damper and a disc drive including the same. 
         [0004]    2. Description of the Related Art 
         [0005]    A disc drive is a device that irradiates light onto a disc to record and read information. The disc may be a compact disc (CD) or a digital video disc (DVD). 
         [0006]    The disc drive includes a pickup, a spindle motor, and a step motor. The pickup reproduces data stored on a disc or records data onto the disc. The spindle motor accommodates a disc on a turn table and rotates the disc. The step motor linearly reciprocates the pickup in a radial direction of the disc. 
         [0007]    Normally, a pickup linearly reciprocates in a radial direction of a disc by a lead screw driven by a step motor. However, due to an external shock, the pickup may abnormally move along a lead screw and a guide shaft. In this case, the pickup may be externally shocked to contact other components of the disc drive. Since the pickup includes a laser diode for irradiating light and an optical system, the laser diode and the optical system may be damaged or an aberration of the optical path may occur due to the external shock. The optical system forms an optical path along which the light irradiated from the laser diode is transmitted. In particular, a drop test of a disc drive is performed in order to measure the durability of the disc drive during manufacture of the disc drive. In this case, the shock is also applied to the pickup. Thus, there may be a need for a device for relieving the shock applied the pickup due to an external source. 
         [0008]    Various methods for preventing shock from being applied to a pickup may have been disclosed. The methods for preventing the shock may have been published in patents that disclose an elastic member for relieving shock applied to a pickup. 
       SUMMARY 
       [0009]    According to an aspect, a pickup damper is provided. The pickup damper is configured to be installed adjacent to a plurality of guide shafts installed on opposite sides of an opening of a base chassis, configured to collide with a pickup and relieve shock via a plurality of steps in response to an external shock being applied, and configured to prevent the pickup from colliding with the guide shafts to protect the pickup. 
         [0010]    The pickup damper may include a plurality of elastic protrusions configured to be installed adjacent to a second guide shaft facing a first guide shaft connected to a step motor on the base chassis, and configured to protrude toward the second guide shaft, and a protrusion configured to protrude from a pickup base at one side of the second guide shaft. The step motor may linearly reciprocate the pickup through the plurality of guide shafts. 
         [0011]    The plurality of elastic protrusions each may be formed as a plastic mold and may be inserted into the base chassis. 
         [0012]    The protrusion may be integrally formed with the base chassis and may be formed by partially bending the base chassis. 
         [0013]    One end of the second guide shaft may be installed adjacent to a turn table on which a disc is to be accommodated. 
         [0014]    The plurality of elastic protrusions may be spaced apart from each other by a predetermined interval, and the protrusion may be spaced apart from each of the plurality of elastic protrusions by a predetermined interval. 
         [0015]    The protrusion may be formed of substantially the same material as the base chassis. 
         [0016]    The protrusion may be formed of aluminum. 
         [0017]    The plurality of steps may include at least three steps. 
         [0018]    In another aspect, a disc drive is provided. The disc drive includes a main frame, a tray on which a disc is configured to be mounted and which is pushed out of or into the main frame, a base chassis configured to be installed on the main frame so as to be moved in up and down directions and on which a pickup is installed so as to linearly reciprocate, and a pickup damper is configured to be installed adjacent to a plurality of guide shafts installed on opposite sides of an opening of a base chassis, configured to collide with a pickup and relieve shock via a plurality of steps in response to an external shock being applied, and configured to prevent the pickup from colliding with the guide shafts to protect the pickup. 
         [0019]    The pickup damper may include a plurality of elastic protrusions configured to be installed adjacent to a second guide shaft facing a first guide shaft connected to a step motor on the base chassis and protrude toward the second guide shaft, and a protrusion that protrudes from a pickup base at one side of the second guide shaft. The step motor may linearly reciprocate the pickup through the plurality of guide shafts. 
         [0020]    The plurality of elastic protrusions each may be formed as a plastic mold and may be inserted into the base chassis. 
         [0021]    The protrusion may be integrally formed with the base chassis and may be formed by partially bending the base chassis. 
         [0022]    One end of the second guide shaft may be installed adjacent to a turn table on which a disc is to be accommodated. 
         [0023]    The plurality of elastic protrusions may be spaced apart from each other by a predetermined interval, and the protrusion may be spaced apart from each of the plurality of elastic protrusions by a predetermined interval. 
         [0024]    In another aspect, a disc drive is provided. The disc drive includes a main frame, a tray on which a disc is configured to be mounted and which is pushed out of or into the main frame, a base chassis configured to be installed on the main frame so as to be moved in up and down directions and on which a pickup is installed so as to linearly reciprocate, and a pickup damper is configured to be installed adjacent to a plurality of guide shafts installed on opposite sides of an opening of a base chassis, configured to collide with a pickup and relieve shock via a plurality of steps in response to an external shock being applied, and configured to prevent the pickup from the guide shafts to protect the pickup. The pickup damper includes a plurality of elastic protrusions configured to be installed adjacent to a second guide shaft facing a first guide shaft connected to a step motor on the base chassis and protrude toward the second guide shaft, and a protrusion that protrudes from a pickup base at one side of the second guide shaft. The step motor linearly reciprocates the pickup through the plurality of guide shafts. 
         [0025]    The plurality of elastic protrusions each may be formed as a plastic mold and may be inserted into the base chassis. 
         [0026]    The protrusion may be integrally formed with the base chassis and may be formed by partially bending the base chassis. 
         [0027]    One end of the second guide shaft may be installed adjacent to a turn table on which a disc is to be accommodated. 
         [0028]    The plurality of elastic protrusions may be spaced apart from each other by a predetermined interval, and the protrusion may be spaced apart from each of the plurality of elastic protrusions by a predetermined interval. 
         [0029]    Other features and aspects may be apparent from the following detailed description, the drawings, and the claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0030]      FIG. 1  is an exploded perspective view illustrating an example of a disc drive including a pickup damper; 
           [0031]      FIG. 2  is a bottom view illustrating an example of a base chassis including the pickup damper shown in  FIG. 1 ; and 
           [0032]      FIGS. 3 through 5  are diagrams illustrating an example of an operation of the pickup damper. 
       
    
    
       [0033]    Throughout the drawings and the detailed description, unless otherwise described, the same drawing reference numerals will be understood to refer to the same elements, features, and structures. The relative size and depiction of these elements may be exaggerated for clarity, illustration, and convenience. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0034]    The following detailed description is provided to assist the reader in gaining a comprehensive understanding of the methods, apparatuses, and/or systems described herein. Accordingly, various changes, modifications, and equivalents of the systems, apparatuses and/or methods described herein will be suggested to those of ordinary skill in the art. Also, descriptions of well-known functions and constructions may be omitted for increased clarity and conciseness. 
         [0035]      FIG. 1  illustrates an example of an exploded perspective view of an example of a disc drive  100  including a pickup damper.  FIG. 2  illustrates an example of a bottom view of a base chassis  120  including the pickup damper  130  shown in  FIG. 1 . 
         [0036]    Referring to  FIGS. 1 and 2 , the disc drive  100  includes a main frame  110 , a tray  140  configured to be pushed out of or into the main frame  110  and to include a mounting portion  141  on which a disc D is to be mounted, a sub frame  111  configured to be rotatably installed on the main frame  110 , and the base chassis  120  supported by the sub frame  111 . 
         [0037]    A sliding member  116  configured to be installed in the main frame  110  to slide in conjunction with a driving motor  115  in a perpendicular direction to a direction in which the tray  140  may be pushed out of or into the main frame  110 . A plurality of cam holes (not shown) may be formed in the sliding member  116  and a plurality of cam protrusions  114  formed on the sub frame  111  may be configured to slide along paths of the cam holes. Thus, the sub frame  111  may be moved in up and down directions with respect to rotation axes  112  and  113  while being supported by the main frame  110 . In this case, the base chassis  120  may also be moved in up and down directions by the sub frame  111 . 
         [0038]    The base chassis  120  includes an opening  121 , a turn table  127  that may accommodate the disc Don the tray  140  and the tray  140  may move into the main frame  110 , a spindle motor  126  (see  FIG. 2 ) that may be coaxially installed with the turn table  127  and rotate the turn table  127 , and a pickup unit  124  that may slide in a radial direction of the disc D accommodated on the turn table  127  to record information on the disc D or to reproduce information recorded on the disc D. The turn table  127 , the spindle motor  126 , and the pickup unit  124  are installed around the opening  121 . 
         [0039]    A first guide shaft  122  and a second guide shaft  123  are configured to face each other across the opening  121  in a longitudinal direction. The longitudinal direction may correspond with a direction in which the tray  140  is pushed out of or into the main frame  110 . A plurality of fix units  1221  and  1222  may fix the first guide shaft  122  to the base chassis  120 . A plurality of fix units  1231  and  1232  may fix the second guide shaft  123  to the base chassis  120 . The fix units  1221 ,  1222 ,  1231 , and  1232  may each be formed as a plastic mold and fix opposites ends of the first guide shaft  122  and opposite ends of the second guide shaft  123  to the base chassis  120 . 
         [0040]    A step motor  128  and a lead screw  129  are installed adjacent to the guide shaft  122 . The lead screw  129  may be configured to rotate in conjunction with the step motor  128  and connected to the pickup unit  124  to linearly reciprocate the pickup unit  124  in a radial direction of the disc D. The pickup unit  124  and the lead screw  129  may be connected to the pickup guide  1241  such that power may be transferred by the pickup guide  1241  to the pickup unit  124 . 
         [0041]    One side of the pickup unit  124  may be slidably connected to the first guide shaft  122  through two connection units  1244  and  1245 . Since the two connection units  1244  and  1245  are formed to surround the first guide shaft  122 , it may be very difficult to separate the two connection units  1244  and  1245  from the first guide shaft  122  without damaging the two connection units  1244  and  1245  or the guide shaft  122 . 
         [0042]    The other side of the pickup unit  124  may be slidably connected to the second guide shaft  123  through a connection unit  1246 . Since the connection unit  1246  is partially opened, the connection unit  1246  may be configured to be detachable from the second guide shaft  123 . 
         [0043]    Thus, in response to an abnormal external shock being applied to the disc drive  100 , the pickup unit  124  may slide through the first guide shaft  122  and the second guide shaft  123 . In response to an external shock being excessively applied to the disc drive  100 , the connection unit  1246  may be separated from the second guide shaft  123 , and thus, the pickup unit  124  may be separated from the second guide shaft  123 . In addition, the pickup unit  124  may collide with the spindle motor  126  that is shocked. 
         [0044]    In order to prevent the collision of the pickup unit  124  and the spindle motor  126 , the disc drive  100  may include the pickup damper  130 . 
         [0045]    The pickup damper  130  may be installed adjacent to one side of the second guide shaft  123 . As an example, the fix unit  1232  around which the spindle motor  126  may be installed, may be formed as a plastic mold, and the fix unit  1232  may include a first buffer protrusion portion  132 , a second buffer protrusion portion  133 , and a third buffer protrusion portion  134 . The first buffer protrusion portion  132  may extend from a body  131  fixed to the base chassis  120  toward an upper portion of the second guide shaft  123  by a predetermined length. The second buffer protrusion portion  133  may be spaced apart from the first buffer protrusion portion  132  by a predetermined interval. The third buffer protrusion portion  134  may be formed by bending the base chassis  120  to protrude towards the upper portion of the base chassis  120  by a predetermined length and may be spaced apart from the second buffer protrusion portion  133  by a predetermined interval. 
         [0046]    The first buffer protrusion portion  132  and the second buffer protrusion portion  133  are configured to be inserted into the base chassis  120 . The first buffer protrusion portion  132  and the second buffer protrusion portion  133  are each formed as a plastic mold, and thus, the first buffer protrusion portion  132  and the second buffer protrusion portion  133  have an elasticity force. The third buffer protrusion portion  134  may be formed of substantially the same material as the material used to form the base chassis  120 . The third buffer protrusion  134  and the base chassis  120  may be formed of aluminum. 
         [0047]    Dampers  1242  and  1243  may be formed on opposite sides of the pickup guide  1241 , respectively. The dampers  1242  and  1243  may prevent the pickup guide  1241  from colliding with the base chassis  120 . 
         [0048]      FIGS. 3 through 5  illustrate an example of an operation of the pickup damper  130 . 
         [0049]    Referring to  FIG. 3 , in response to abnormal external shock being applied, for example, an abnormal external shock applied in a drop test, the pickup unit  124  may slide in a direction indicated by an arrow and substantially simultaneously the connection unit  1246  may contact the first buffer protrusion portion  132 . Due to the pickup unit  124  contacting the first buffer protrusion portion  132 , a shock applied to the pickup unit  124  may be significantly reduced. 
         [0050]    Referring to  FIG. 4 , due to the external shock, the pickup unit  124  may push the first buffer protrusion portion  132  such that the first buffer protrusion portion  132  contacts the second buffer protrusion portion  133 . Since the first buffer protrusion portion  132  has an elastic body, the first buffer protrusion portion  132  may be elastically deformed. In this case, due to the pickup unit  124  contacting the first buffer protrusion portion  132  and the second buffer protrusion portion  133 , the shock applied to the pickup unit  124  may be further reduced. 
         [0051]    Referring to  FIG. 5 , due to the external shock, the pickup unit  124  may push the first buffer protrusion portion  132  and the second buffer protrusion portion  133  such that the second buffer protrusion portion  133  may contact the third buffer protrusion portion  134 . Since the second buffer protrusion portion  133  has an elastic body, the second buffer protrusion portion  133  may be elastically deformed. As an aspect, the third buffer protrusion portion  134  may not be elastically deformed and may contact the second buffer protrusion portion  133 . In this case, due to the pickup unit  124  contacting the first buffer protrusion portion  132 , the second buffer protrusion portion  133 , and the third buffer protrusion portion  134 , the shock applied to the pickup unit  124  may be yet further reduced. 
         [0052]    A switch  142  may be installed on a front surface of the tray  140  and may output a signal for loading or unloading the tray  140  on or from the main frame  110 . 
         [0053]    An upper surface of the main frame  110  is covered by the tray  140 . A clamp  151  for clamping the disc D installed on the turn table  127  may be installed on the tray  127 . 
         [0054]    According to the present application, a pickup damper and a disc drive including the pickup damper may gradually relieve shock applied to a pickup and substantially simultaneously may prevent the pickup from being separated from a guide shaft in response to a drop test being performed or an external shock being applied. 
         [0055]    A number of examples have been described above. Nevertheless, it will be understood that various modifications may be made. For example, suitable results may be achieved if the described techniques are performed in a different order and/or if components in a described system, architecture, device, or circuit are combined in a different manner and/or replaced or supplemented by other components or their equivalents. Accordingly, other implementations are within the scope of the following claims.