Abstract:
An optical disc apparatus which has a lock mechanism including a hook to engage with an optical pickup&#39;s part which is to be locked. It also has a lock member which turns around a fulcrum as a sliding member slides when an optical disc is loaded or unloaded. When the sliding member is not in touch with the lock member, the hook turns in a direction to engage with the part to be locked and locks the optical pickup, and when the sliding member is in touch with it, the hook turns in a direction to disengage from the part to be locked and unlocks the optical pickup. This improves impact resistance when a disc is unloaded.

Description:
CLAIM OF PRIORITY  
       [0001]     The present application claims priority from Japanese application serial No. P2005-218460, filed on Jul. 28, 2005, the content of which is hereby incorporated by reference into this application.  
       BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates to an optical disc apparatus and more particularly to a structure which prevents damage to a apparatus in transportation by locking an optical pickup while no optical disc is loaded.  
         [0004]     2. Description of the Related Art  
         [0005]     Among techniques related to the present invention is the one disclosed in JP-A No. 339880/2000. This gazette describes a structure in which, when a disc drive section having a turntable and an optical pickup is in its standby position, a limiting piece provided on the optical pickup is limited by a side wall surface of a projection formed on a bottom chassis so as to limit the movement of the optical pickup.  
         [0006]     However, as apparent from an illustration of the structure, the prior art described in JP-A No. 339880/2000 is intended to be applied to an optical disc apparatus (for example, a half-height model) whose thickness may be approx. 25×10 −3  m or more, where the projection is located at a disc innermost side position remotely from the fulcrum of vertical motion of the disc drive section (unit mechanical part) so that the optical pickup is locked or unlocked at that position. The conventional structure can be embodied only when the disc drive section (unit mechanical part) can move up and down at the projection sufficiently. Therefore, in a certain type of optical disc apparatus in which the disc drive section cannot be moved up and down sufficiently, such as a slim slot drive model, there are many difficulties in embodying the prior art.  
         [0007]      FIG. 5  shows an example of a structure in which the above prior art is introduced into a slim slot drive model and a projection is provided so as to allow the unit mechanical part to move up and down sufficiently to unlock the optical pickup for disc loading. A pickup stopper  200  as the projection is provided on the inner surface of a bottom case  20  at a position that makes it possible to unlock the pickup as mentioned above. When a disc is unloaded (no disc is loaded), an optical pickup  13  is at the disc outermost side position near the fulcrum of vertical motion with the unit chassis  50  down on the bottom case  20  and the optical pickup  13  is away from the pickup stopper  200  by distance L. If an impact should be given in this condition, for example, during transportation, the optical pickup  13  would move toward the pickup stopper  200  and might collide against the pickup stopper  200  and break. In  FIG. 5 , numeral  11  represents a disc motor;  12  represents a turntable;  30  represents a slide motor for rotating a lead screw  31 ; and  40  represents a loading motor for loading an optical disc.  
         [0008]     The present invention has been made in view of the above circumstances of the prior art and concerns a simple structure for a slim slot drive type optical disc apparatus or the like in which, when a disc is unloaded, an optical pickup is locked to prevent damage to it upon impact.  
         [0009]     The primary object of the invention is to provide a reliable optical disc apparatus which solves the above problem.  
       SUMMARY OF THE INVENTION  
       [0010]     The present invention offers a technique which solves the above problem.  
         [0011]     According to the present invention, in an optical disc apparatus, a lock mechanism which locks an optical pickup when an optical disc is unloaded, and unlocks the optical pickup when the optical disc is loaded, includes a lock member which has a hook to engage with the optical pickup&#39;s part to be locked and turns around a fulcrum depending on a sliding member which slides when an optical disc is loaded or unloaded. When the sliding member is not in touch with the lock member, the hook turns in a direction to engage with the part to be locked and locks the optical pickup, and when the sliding member is in touch with it, the hook turns in a direction to disengage from the part to be locked and unlocks the optical pickup.  
         [0012]     According to the present invention, in an optical disc apparatus, an optical pickup is protected from impact, etc. in transportation or a similar situation by a simple structure so that reliability of the apparatus is improved. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]      FIG. 1  shows an example of a structure of a front side of an optical disc apparatus according to an embodiment of the present invention;  
         [0014]      FIG. 2  shows an example of a back side of the optical disc apparatus of  FIG. 1 ;  
         [0015]      FIG. 3  shows a lock mechanism of an optical pickup of the optical disc apparatus of  FIG. 1 ;  
         [0016]      FIGS. 4A and 4B  are flowcharts explaining operational sequences of the lock mechanism of  FIG. 3  where  FIG. 4A  shows a disc unloading process and  FIG. 4B  shows a disc loading process; and  
         [0017]      FIG. 5  illustrates the problem to be solved by the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0018]     Next, a preferred embodiment of the present invention will be described referring to the accompanying drawings.  
         [0019]      FIG. 1  to  FIG. 4B  are explanatory drawings for an embodiment of the invention.  FIGS. 1 and 2  show the general structure of an optical disc apparatus according to the embodiment of the invention;  FIG. 3  shows the structure of a lock mechanism of an optical pickup of the optical disc apparatus as shown in  FIGS. 1 and 2 ; and  FIGS. 4A and 4B  explain operational sequences of the lock mechanism of  FIG. 3 . In FIGS.  1  to  3 , the same constituent elements are designated by the same reference numerals and the same coordinate axes are used.  
         [0020]      FIG. 1  shows an example of a structure of a front side (disc loading side) of the optical disc apparatus according to the embodiment of the present invention; and  FIG. 2  shows an example of a structure of a back side (opposite of the disc loading side) of the apparatus.  
         [0021]     In  FIG. 1 , numeral  1  represents an optical disc apparatus;  11  represents a disc motor which rotates an optical disc (not shown);  12  represents a turntable on which an optical disc rests;  13  an optical pickup;  13   a  represents an objective lens;  20  represents a bottom case which covers the back side of the optical disc apparatus  1 ;  31  represents a lead screw member with a threaded surface which moves the optical pickup in a virtually radial direction of an optical disc (not shown) by rotation of the thread;  30  represents a feed motor which rotates the lead screw member  31 ;  32  and  33  represent guide members which guide movement of the optical pickup  13 ;  60  represents a base member as a apparatus platform;  50  represents a unit mechanical deck which bears the abovementioned disc motor  11 , optical pickup  13 , feed motor  30 , lead screw member  31 , guide members  32  and  33  and so on and can move up and down with respect to the base member  60 ;  121 ,  122  and  123  represent lever members which, when an optical disc is inserted into the apparatus from the front panel (not shown) in the Y-axis direction and when an optical disc is unloaded from the apparatus toward the front panel, transmit driving power for the insertion and unloading;  123   a  represents a turn fulcrum for the lever member  123 ;  124  represents a slide arm member connected to the lever member  123 ;  40  represents a loading motor;  160  represents a switch which turns on and off the driving power to the loading motor  40 ;  161  represents a switch activating arm member which activates the switch  160 ;  155  represents a spring which biases the switch activating arm member  161 ;  161   a  represents a switch contact of the switch activating arm member  161 ;  41  represents a transmission which transmits the rotary driving power of the loading motor  40  to the lever member  121 ;  170  represents a lifting mechanism, located on the base member  60 , which, during loading of an optical disc, moves up and down the unit mechanical deck  50  with the optical disc in place in the apparatus;  143  represents an arm member which transmits driving power to the lifting mechanism  170 ;  153  represents a spring which biases the arm member  143 ; A represents an area (hereinafter called the lock mechanism for the sake of simplicity) where there is a lock mechanism which locks the optical pickup  13  to make it unmovable when a disc is unloaded; B and C represent locations of fulcrums of vertical motion for the unit mechanical deck  50  (hereinafter called the fulcrums of vertical motion for the sake of simplicity); and line PP′ represents a line which connects the fulcrums of vertical motion B and C (hereinafter called the fulcrum line). While the unit mechanical deck  50  moves up or down, it turns around the fulcrum line PP′.  
         [0022]     In  FIG. 2 , numeral  140  represents a lock member which locks the optical pickup  13  into a specified position (disc unloading position) inside the optical disc apparatus in the lock mechanism A (with no disc loaded);  140   a  represents a hook for the lock member  140 ;  140   c  represents a turn fulcrum for the lock member  140 ;  140   d  represents a recessed surface of the lock member  140 ;  150  represents a spring which biases the lock member  140  in the counterclockwise direction with respect to the turn fulcrum  140   c ;  131  represents a projection on the pickup  13  as a part to be locked; and arrow E represents the direction of movement of the slide arm member  124 . Other numerals and symbols are the same as those shown in  FIG. 1 . The lock member  140  turns around the turn fulcrum  140   c  in a plane virtually parallel to the rotation plane of the optical disc. The transmission  41  consists of a gear train.  
         [0023]     In the above lock mechanism A, when the lock member  140  is out of touch with or in touch with the slide arm member  124 , it locks or unlocks the optical pickup  13  respectively. Specifically, when the optical disc loaded in the optical disc apparatus  1  is released, or unloaded, the slide arm member is released from the recessed surface  140   d  of the lock member  140  and moved back toward the direction opposite to the direction of arrow E. As the lock member  140  is released from the slide arm member  124 , it turns around the turn fulcrum  140   c  counterclockwise and engages the hook  140   a  with the projection  131  of the optical pickup  13  at the disc unloading position and locks the optical pickup  13 . On the other hand, when the optical disc is inserted into the optical disc apparatus  1  and loaded, the slide arm member  124  moves forward in the direction of arrow E and comes into touch with the recessed surface  140   d  of the lock member  140 . When the lock member  140  touches the slide arm member  124 , it receives an external force from the slide arm member  124  and turns around the turn fulcrum  140   c  clockwise; and upon completion of disc loading, it releases the hook  140   a  from the projection  131  of the optical pickup  13  at the disc loading position and unlocks the optical pickup  13 .  
         [0024]     In the structure shown in  FIGS. 1 and 2 , when an Eject button (not shown) is pressed to unload the optical disc from the optical disc apparatus  1 , the loading motor  40  rotates and the lever members  121  and  122  are driven by the rotary driving power through the transmission  41  and the driving power of the lever member  122  is transmitted through the arm member  143  to the lifting mechanism  170 . The lifting mechanism  170  turns the unit mechanical deck  50  around the fulcrum line PP′ to move down the unit mechanical deck member  50  from the height of its loading position in the -Z-axis direction. Concurrently with the movements of the lever members  121  and  122  and the descent of the unit mechanical deck  50  through the lifting mechanism  170 , the lever member  122  drives the lever member  123  to turn around the turn fulcrum  123   a  and consequently the slide arm member  124 , connected with it, moves back in the direction opposite to the direction of arrow E. As the slide arm member  124  moves back in this way, it is released from the recessed surface  140   d  of the lock member  140 . When the lock member  140  is released from the slide arm member  124 , it turns around the turn fulcrum  140   c  counterclockwise and engages the hook  140   a  with the projection  131  of the optical pickup  13  and locks the optical pickup  13 .  
         [0025]     On the other hand, as the optical disc is inserted into the optical disc apparatus  1  and loaded, the loading motor  40  rotates and the lever members  121  and  122  are driven by the rotary driving power through the transmission  41  and the driving power of the lever member  122  is transmitted through the arm member  143  to the lifting mechanism  170 . The lifting mechanism  170  turns the unit mechanical deck  50  around the fulcrum line PP′ to move up the unit mechanical deck member  50  in the Z-axis direction, for example to a position at which the inner circumference of the optical disc touches part of a top case (case which covers the front side of the apparatus) so that the optical disc is chucked onto the surface of the turntable  12 . After chucking, the lifting mechanism  170  again turns the unit mechanical deck  50  around the fulcrum line PP′ to move it down in the -Z-axis direction to the height of the specified loading position. Concurrently with these movements, the lever member  122  drives the lever member  123  to turn around the turn fulcrum  123   a  and consequently the slide arm member  124  moves forward in the direction of arrow E and touches the recessed surface  140   d  of the lock member  140 . When the lock member  140  is in touch with the slide arm member  124 , it receives an external force from the slide arm member  124  and turns around the turn fulcrum  140   c  clockwise; after the above disc loading sequence is completed, namely after the unit mechanical deck  50  comes to the height of the specified loading position, the hook  140   a  of the lock member  140  is released from the projection  131  of the optical pickup  13  at the disc loading position and unlocks the optical pickup  13 . After the optical pickup  13  is unlocked, it is driven by the lead screw  31  which is rotated by the feed motor  30 , and guided by the guide members  32  and  33  so that it can move in a virtually radial direction of the optical disc for recording or playback.  
         [0026]     The same constituent elements as those shown in  FIGS. 1 and 2  are designated by the same reference numerals and symbols as used in  FIGS. 1 and 2 .  
         [0027]      FIG. 3  shows the structure of the lock mechanism A of the optical pickup  13  in the optical disc apparatus  1  shown in  FIGS. 1 and 2 .  
         [0028]     In  FIG. 3 , numeral  124   a  represents a tip of the slide arm member  124 ;  140   b  an arm of the lock member  140 ;  140   e  a spring connection of the lock member  140 ; arrows E and F directions of movement of the slide arm member  124 ; and arrows G and H directions of turn of the lock member  140 . The lock member  140  is biased in a direction to engage the hook  140   a  with the projection  131  of the optical pickup  13  by means of a spring  150 .  
         [0029]     When the optical disc apparatus  1  changes its state from the disc unloading state to the disc loading state, there occurs a transition in the optical pickup  13  from the locked state ( FIG. 2 ) to the unlocked state. In this case, as mentioned earlier, the slide arm member  124  moves in the direction of arrow E (forward) and its tip  124   a  touches the recessed surface  140   d  of the lock member  140 , which turns the lock member  140  in the direction of arrow G against the resilience of the spring  150  and releases the hook  140   a  from the projection  131  of the optical pickup  13 , thereby unlocking the optical pickup  13 . The other way around, when the optical disc apparatus  1  changes its state from the disc loading state to the disc unloading state, there occurs a transition in the optical pickup  13  from the unlocked state to the locked state ( FIG. 2 ). In this case, the slide arm member  124  moves in the direction of arrow F (backward) and its tip  124   a  moves away from the recessed surface  140   d  of the lock member  140 . As a consequence, the resilience of the spring  150  turns the lock member  140  in the direction of arrow H and engages the hook  140   a  with the projection  131  of the pickup  13 , thereby locking the optical pickup  13 .  
         [0030]      FIGS. 4A and 4B  are flowcharts which explain the operational sequences of the lock mechanism of  FIG. 3 , where  FIG. 4A  shows a disc unloading process and  FIG. 4B  shows a disc loading process.  
         [0031]     Referring to  FIG. 4A , the disc unloading process is explained below.  
         [0000]     (1) When a command to unload an optical disc is given to the optical disc apparatus  1 , for example, by pressing the Eject button, the optical disc apparatus  1  starts the loading motor  40  (step S 411 ).  
         [0032]     (2) The rotary driving power of the loading motor  40  drives the lifting mechanism  170  through the transmission  41  and lever members  121  and  122  and the lifting mechanism  170  begins to move down the unit mechanical deck  50  from the height of its optical disc loading position (step S 412 ).  
         [0000]     (3) The driving power of the loading motor  40  moves the slide arm member  124  in the direction of arrow F (backward) through the transmission  41  and lever members  121 ,  122  and  123  and releases it from the lock member  140  (step S 413 ).  
         [0000]     (4) The lock member  140  turns toward the projection  131  of the optical pickup  13  (in the direction of arrow H) by the resilience of the spring  150  (step S 414 ).  
         [0000]     (5) As the hook  140   a  turns, it engages with the projection  131  of the optical pickup  13  and the optical pickup  13  is locked (step S 415 ). In this locked state, the optical disc is ready to be unloaded.  
         [0033]     Referring to  FIG. 4B , the disc loading process is explained below.  
         [0000]     (1) As an optical disc is inserted into the optical disc apparatus  1 , the optical disc apparatus  1  starts the loading motor  40  (step S 421 ).  
         [0034]     (2) The rotary driving power of the loading motor  40  drives the lifting mechanism  170  through the transmission  41  and lever members  121  and  122  and the lifting mechanism  170  moves up the unit mechanical deck  50  to let it start chucking the optical disc (step S 422 ).  
         [0000]     (3) The driving power transmitted from the lever member  123  through the lever member  122  moves the slide arm member  124  in the direction of arrow E (forward) (step S 423 ).  
         [0000]     (4) As the slide are member  124  moves, it touches the recessed surface  140   d , which turns the lock member  140  in the direction of arrow G against the resilience of the spring  150  (step S 424 ).  
         [0035]     (5) As the lock member  140  turns, the hook  140   a  is released from the projection  131  of the optical pickup  13  and the optical pickup  13  is unlocked (step S 425 ). As a result, the optical pickup  13  can move in a virtually radial direction of the optical disc.  
         [0036]     At the above steps S 411  to S 415  and S 421  to S 425 , the loading motor  40  is controlled according to control signals from a control means for the optical disc apparatus  1  such as a microcomputer.  
         [0037]     According to the above embodiment, the optical disc apparatus has a simple structure which locks the optical pickup when a disc is unloaded and prevents damage to the optical pickup in transportation or a similar situation.  
         [0038]     The present invention may be embodied in other forms without departing from the spirit and major features thereof. Therefore, it should be understood that the above embodiment is just illustrative and not restrictive in terms of interpretation of the invention. The scope of the present invention is indicated in the appended claims. Variations and modifications that fall within equivalents of the appended claims are embraced by the claims.