Abstract:
A first detector is provided for detecting an optical disc inserted in an opening of a reproducing system and for producing a first signal, and a second detector is provided on a reproducing device for detecting the disc carried to the device and for producing a second signal. A sensing circuit is provided for sensing a temporary reduction of a voltage of power supplied to the system and for producing a temporary reduction signal. A control means is provided to be responsive to the first signal and to the temporary reduction signal for operating a carrying device to carry the disc in an unloading direction, and in a loading direction when the disc reaches a predetermined position.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a system for reproducing a recording medium, and more particularly relates to a car CD player. 
     In the car CD player, when a user inserts a CD (compact disc) in an opening of the player, the CD is automatically carried in the player and mounted on a turntable of the player. When the user depresses an eject button, the CD is discharged. 
     The car CD can be operated by positioning the key switch at the ACC (accessory) if the engine is stopped. When the key switch is positioned at the START in order to start the engine, the power supply to the CD player is temporarily stopped so as to keep the rated voltage to the starter of the engine. 
     If the key switch is rotated to the START during the carrying of the CD to the turntable or to the opening, the CD may begin an unexpected operation or affect the carrying operation when the power is supplied to the CD player after the starting of the engine. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to provide a reproducing system which may properly continue to carry the CD after the starting of the engine. 
     According to the present invention, there is provided a system for reproducing a recording medium, the system having a reproducing device, a carrying device for carrying a recording medium inserted in an opening of the system to the reproducing device, the system comprising, a first detector for detecting the recording medium inserted in the opening and for producing a first signal, a second detector provided on the reproducing device for detecting the recording medium carried to the device and for producing a second signal, sensing means for sensing a temporary reduction of a voltage of power supplied to the system and for producing a temporary reduction signal, control means responsive to the first signal for operating the carrying device to carry the recording medium in a loading direction, and responsive to the first signal and to the temporary reduction signal for operating the carrying device to carry the recording medium in an unloading direction, and in a loading direction when the recording medium reaches a predetermined first position. 
     The control means is also responsive to disappearance of the second signal and to the temporary reduction signal for operating the carrying device to carry the recording medium in the loading direction, and in the unloading direction when the recording medium reaches a predetermined second position. 
     A third detector is provided at the predetermined first position for producing a third signal for carrying the recording medium in the loading direction when the recording medium reaches the third detector. 
     The third detector is disposed at a position inner than the first detector. 
    
    
     BRIEF DESCRIPTION OF DRAWINGS 
     FIG. 1 is a perspective view showing a main part of a reproducing system mounted on a car; 
     FIGS. 2 a  and  2   b  are plan views showing a tray and a CD; 
     FIG. 3 is a diagram showing an arrangement of photodetectors; 
     FIGS. 4 a  to  4   d  are photodetectors; 
     FIGS. 4 e  and  4   f  are tables for explaining operation of the photodetector; 
     FIG. 5 is a block diagram showing a control circuit for controlling a loading mechanism; 
     FIGS. 6 to  9  are illustrations for explaining disc loading operation; 
     FIG. 10 shows output waveforms of the photodetector and switches; 
     FIG. 11 shows a waveform of a detector; 
     FIGS. 12 to  14  show various discs; and 
     FIG. 15 is a plan view of an adapter. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to FIG. 1, the system of the present invention has a pair of disc carrying mechanisms  1  and  2 , a reproducing device  3 , a pair of shafts  5   a  and  5   b  mounted on a fixed chassis  5 . 
     The reproducing device  3  has a clamp mechanism  3 , a pickup mechanism  4  mounted on a movable chassis  6 . 
     The pickup mechanism  4  is horizontally rotatably mounted on the movable chassis  6  by a shaft  8  and vertically rotatably mounted on a shaft  7  on the chassis. 
     A drive pin  11  is engaged with a guide hole  9  of the movable chassis  6  and with an elongated hole  10  of the pickup mechanism  4 . By moving the drive pin  11 , the pickup mechanism  4  and the cramp mechanism  3  are rotated about the shaft  8 . 
     A home switch HSW is provided on the pickup mechanism  4 . 
     The clamp mechanism  3  has a circular hub  3   a  for clamping a disc DS on a turntable (not shown). 
     As shown in FIG. 2 a , a tray  12  has a disc supporting plate  12   b  having a V-shaped notch  12   a . On the both sides of the plate  12   b , there is provided a pair of holes  12   c ,  12   d  in which shafts  5   a ,  5   b  (FIG. 1) are to be engaged. 
     In the V-shaped notch  12   a , the pickup mechanism  4  and clamping mechanism  3  are to be positioned at the reproduction of the disc DS. 
     In the present embodiment, six trays  12  are stacked and supported by the shafts  5   a ,  5   b.    
     An elevating mechanism (not shown) is provided to be engaged with side plates of a lowermost tray so as to elevate the stack of the trays along the shafts  5   a ,  5   b.    
     The disc carrying mechanisms  1 ,  2  are positioned toward the tray in the operating state (FIG. 2 a ), and retracted in the non-operating state (FIG. 2 b ) when the trays are vertically moved. 
     The disc carrying mechanism  1  comprises a roller  1   a  and an engaging plate  1   b . The roller  1   a  is connected to a rotating shaft of a motor  13  by a transmitting mechanism  1   c  composed by a gear mechanism and a belt mechanism so as to be rotated. 
     The disc carrying mechanism  2  has the same construction as the mechanism  1 . Thus, when an operation switch is operated, the rollers  1   a ,  2   a  are rotated, thereby carrying the disc DS inserted in the front opening and in the space between the rollers  1   a ,  2   a  to the turntable and discharging the disc. 
     FIG. 12 shows a CD DS 1  of 12 cm diameter, FIG. 13 shows a Maxi single CD DS 2  of 12 cm diameter, and FIG. 14 shows a CD DS 3  of 8 cm diameter. 
     The 12 cm CD of FIG. 12 has a center hole of 15 mm inner diameter, a clamping area of 33 mm diameter, and a program area between the clamping area and the periphery. The Maxi single CD of FIG. 13 has a same central hole and a clamping area as the 12 cm CD, and a program area between the clamping area and the circle of 50 mm-82 mm. An outside area AR may be transparent or opaque, and may be painted and drawn. The 8 cm CD of FIG. 14 has a same center hole and a clamping area as the 12 cm CD, and an outside program area. 
     FIG. 15 shows an adapter AD. The adapter has a 12 cm diameter and a circular hole BR having a diameter of about 80 mm in which the 8 cm CD can be set. Thus, the 8 cm CD can be used as the 12 cm CD with the adapter. 
     A controller for controlling the disc carrying mechanisms  1 ,  2  will be described hereinafter with reference to FIGS. 3 and 4. 
     Referring to FIG. 3, there is provided a first photodetector P 1  outside the roller  1   a , a second photodetector P 2  inside the roller  2   a , and a mechanical side switch PSW at the disc carrying plane of the roller  2   a.    
     The first and second photodetectors P 1  and P 2  are disposed at a distance smaller than the diameter of the 8 cm CD. The first photodetector P 1  detects the insertion of a CD in order to drive the rollers  1   a ,  2   a , and the second photodetector P 2  detects a rear periphery of a discharged CD, thereby stopping the rollers  1   a  and  2   a.    
     The side PSW contacts with the 12 cm CD between the roller  2   a  and the engaging plate  2   b , thereby detecting the existence of the 12 cm CD. The distance between the first photodetector P 1  and the side switch PSW is larger than the diameter of 8 cm CD. 
     Referring to FIGS. 4 a  and  4   b , each of the photodetectors P 1  and P 2  comprises a photodiode and phototransistor which are opposed. As shown in the truth table of FIG. 4 e , when the phototransistors are closed by the CD, the outputs SP 1  and SP 2  become high H. 
     Referring to FIGS. 4 c  and  4   d , when the CD contacts with the switches PSW and HSW, outputs SPSW and SHSW of transistors become low L as shown in FIG. 4 f.    
     Referring to FIG. 5, the control circuit comprises a CPU  14 , roller driving motor  13 , motor driving circuit  15 , actuator driving circuit  16  for driving the elevating mechanism, spindle motor  4   a  (FIG. 1) of the pickup  4 , temporary power cut off detecting circuit  17 , and ROM  18  storing a program for controlling the reproduction system. Furthermore, there is provided a push button operating section  19 , display  20  and a power source circuit  21 . 
     The operation for loading discs are described with reference to FIGS. 6 through 9. 
     Referring to FIG. 6, when the 12 cm CD DS 1  or the adapter in which the 8 cm CD DS 3  is mounted is inserted in the opening of the reproducing system, the first photodetector P 1  detects the inserted CD DS 1  earlier than the second photodetector P 2 . Therefore, the output SP 1  becomes H earlier than the output SP 2 . In response to the output SP 1 , the CPU  14  operates the driving motor  13  at a time tm so that the carrying rollers  1   a ,  2   a  are rotated in the forward direction. Thus, the loading of the CD starts. When the CD closes the side switch PSW, the output SPSW becomes low at a time tc. 
     When the CD reaches the home position, the home switch HSW is closed, thereby the output SHSW becomes low. In response to the output SHSW, the CPU stops the driving of the rollers  1   a ,  2   a.    
     Referring to FIG. 7 when the Maxi single CD is inserted in the opening, the first photodetector P 1  detects the inserted CD DS 1  earlier than the second photodetector P 2 . Therefore, the output SP 1  becomes H earlier than the output SP 2 . In response to the output SP 1 , the CPU  14  operates the driving motor  13  at a time tm so that the carrying rollers  1   a ,  2   a  are rotated in the forward direction. Thus, the loading of the CD starts. When the CD closes the side switch PSW, the output SPSW becomes low at a time tc. 
     When the CD reaches the home position, the home switch HSW is closed, thereby the output SHSW becomes low. In response to the output SHSW, the CPU stops the driving of the rollers  1   a ,  2   a.    
     Referring to FIG. 8 when the Maxi single CD is inserted in the opening. 
     When a Maxi single disc having a transparent outside area AR is inserted, the outputs SP 1  and SP 2  are produced at positions shown by solid lines in FIG.  7 . 
     Referring to FIG. 8 when an adapter AD on which an 8 cm CD is not mounted is inserted in the opening, the first photodetector P 1  detects the inserted adapter AD earlier than the second photodetector P 2 . Therefore, the output SP 1  becomes H earlier than the output SP 2 . In response to the output SP 1 , the CPU  14  operates the driving motor  13  at a time tm so that the carrying rollers  1   a ,  2   a  are rotated in the forward direction. Thus, the loading of the CD starts. 
     When the hole BR reaches the first photodetector P 1 , the output SP 1  becomes L at a time tAD. The CPU determines that the adapter without 8 cm CD is inserted based on the fact that the output SP 1  becomes low L before the output SPSW. 
     The CPU operates to rotate rollers  1   a ,  2   a  in the reverse direction, thereby discharging the adapter AD. 
     Referring to FIG. 9, when the 8 cm CD DS 3  is inserted in the opening, the first photodetector P 1  detects the inserted CD DS 3  earlier than the second photodetector P 2 . Therefore, the output SP 1  becomes H earlier than the output SP 2 . In response to the output SP 1 , the CPU  14  operates the driving motor  13  at a time tm so that the carrying rollers  1   a ,  2   a  are rotated in the forward direction. Thus, the loading of the CD starts. 
     In the case of the 8 cm CD, the output SPSW does not become L, and the output SP 1  becomes L. The CPU detects the insertion of the 8 cm CD DS 3  based on the fact that the output SP 1  becomes low in the condition that the output SPSW is L. Based on the detection of 8 cm CD, the CPU  14  rotates the rollers  1   a ,  2   a  in the reverse direction, thereby discharging the 8 cm CD. 
     The unloading operation will be described with reference to FIG.  10 . 
     When a user instructs the unloading of a desired CD on one of the trays  12 , the pickup mechanism  4  and clamp mechanism  3  are returned to the retracted position of FIG. 1, and the stack of trays is vertically moved so that the tray mounting the desired CD is positioned at the rollers  1   a ,  2   a . Thus, the unloading operation starts. 
     As shown in FIG. 10, outputs SP 1 , SP 2 , SPSW and SHSW are produced when the disc passes the photodetectors P 1 , P 2 , switches DSW, HSW. 
     When the output SPSW becomes L, and the output SP 2  becomes L (time tb), the CPU  14  stops the rotation of the rollers  1   a ,  2   a  (time ts). As a result, the CD stops in the condition that the CD is gripped by the rollers  1   a ,  2   a  and engaging plates  1   b ,  2   b . Therefore, the CD is prevented from falling away from the opening of the reproducing device. 
     When the user takes out the CD, the output SP 1  becomes L. Thus, the unloading of the CD finishes. 
     In the above described loading operation of the 12 cm CD or the adapter AD mounting the 8 cm CD shown in FIGS. 6 and 7, if the power supplied from a battery  100  (FIG. 5) of the car is temporarily cut or reduced at the starting of the engine of the car, the CD may be stopped in a period τ of FIGS. 6 and 7, where the output SPSW is to be at the low L. 
     When the period of the temporary cut of power supply ends and the power is supplied to the reproducing system, the CD is carried thereby the output SPSW becomes H. Next, when the output SP 1  becomes L, the condition is equal to the condition of the 8 cm CD at the time tr of FIG.  9 . Therefore, the CPU  14  misjudges the CD as the 8 cm CD, so that the 12 cm CD or the adapter is discharged. 
     The present invention is to resolve such trouble. 
     When the power supply is temporarily cut during the loading or unloading of the CD, the temporary power cut detection circuit  17  of FIG. 5 detects the reduction of the voltage VBT of the power and produces a cut signal SB at a high level as shown in FIG.  11 . 
     In the loading operation, in response to the signal SB, the CPU  14  operates to rotate the rollers  1   a  and  2   a  in the reverse direction after the recovery of the power supply, so that the CD is carried in the discharge direction. When the CD passes the photodetector P 2  and the output SP 2  becomes L, the CPU operates to rotate the rollers  1   a  and  2   a  in the feeding direction. When the home switch HSW is operated by the CD and the output SHSW becomes L, the rotation of the rollers are stopped. Thus, the CD is loaded on the turntable, and the CD is normally reproduced. 
     In the unloading operation, in response to the signal SB, the CPU  14  operates to rotate the rollers  1   a  and  2   a  in the forward direction after the recovery of the power supply, so that the CD is carried in the loading direction. When the CD contacts with the home switch HSW and the output SHSW becomes L, the CPU operates to rotate the rollers  1   a  and  2   a  in the reverse direction. When the CD passes the photodetector P 2 , and the output SP 2  becomes L, the rotation of the rollers are stopped. Thus, the CD is unloaded from the system. 
     In accordance with the present invention, if the power supply is temporarily cut during loading or unloading, the CD is normally carried after resupply of the power.