JPH0514364Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a disc player, and more particularly to a disc player that plays back a disc on which program information including address information is recorded.

BACKGROUND ART In this type of disk player, recorded information is read by the information reading point of the pickup following the recording track of the disk, but when vibrations are applied to the player body from the outside, etc. The pick-up information reading point will skip over the recording track, making it impossible to obtain stable playback operation. In particular, when considering installation in an automobile that constantly vibrates, there is a high possibility that so-called truck jumping will occur frequently, and countermeasures are desired.

Summary of the invention This invention was created in view of the points mentioned above.
To provide a disk player capable of quickly and reliably detecting a track jump and smoothly performing a subsequent return operation.

The disk player according to the present invention includes a counter that counts at a constant cycle and outputs expected address information in sequence, independently of the address information read by the pick-up, and performs a count operation at a constant cycle based on the latest address information read by the pick-up. The method is characterized in that it compares the expected address information obtained by the method, determines that a track skip has occurred due to a mismatch between the two address information, and moves the pickup to the expected address.

Embodiment Hereinafter, a vehicle-mounted autoloading disk player as an embodiment of the present invention will be described with reference to the accompanying drawings.

In the figure, reference numeral 1 indicates the entire autoloading disc player.

As shown in FIG. 1, a front panel 3 forming a part of the housing 2 is provided with a slot 3a extending in the left-right direction into which a disc 5 to be played is inserted. However, the left and right direction referred to here refers to the front direction indicated by arrow Y. Therefore, the arrow X direction in the figure indicates leftward, and the arrow Z direction indicates upward. The disk 5 is of a type that records and reads signals using laser light, and has an outer diameter of about 12 cm. The front panel 3 is also provided with a group of operation buttons 6 for operating the disc player, such as play start and eject.

Inside the housing 2, mechanisms such as a loading mechanism and a pick-up moving mechanism are formed. As these mechanisms, for example, those described in the specification and drawings filed by the present applicant as Japanese Patent Application No. 1983-72041 can be used.

A block diagram of the control system is shown in FIGS. 2 and 3, which includes a host microcomputer (hereinafter referred to as host microcomputer) 200, which is the first control unit that controls the entire system, and at least an operation unit 201 and a control system. It includes a sub-microcomputer (hereinafter referred to as sub-microcomputer) 203, which is a second control unit that controls the display section 202. These microcomputers 200 and 203 are mounted on mutually separated units, and are It is connected via a voltage power line 205 and a communication line 206. Although the main power is supplied to the host microcomputer via the sub-microcomputer, it is of course possible to supply the main power directly to the host microcomputer. In addition, signals emitted from the aforementioned operation button group 6, and detection switches such as a play start switch 93 and a detection switch 103, which will be described later, are supplied to the host microcomputer 200 or the sub-microcomputer 203.

When the so-called accessory switch 207 of the automobile, which controls on/off of the main power supply, is turned on and closed, the power supply voltage V _DD stabilized by the stabilization circuit 208 rises instantaneously as shown in FIG. 4a. Reset circuit 2
The output of 09 gradually rises with a predetermined time constant with respect to the power supply voltage a as shown in FIG. 4b, and reaches a predetermined level V ₁
The host microcomputer 200 is reset when it reaches this point. The host microcomputer 200 issues a control signal after a certain period of time T has elapsed from the reset point, and
In order to supply the sub-microcomputer 203 with the power supply voltage _VDD , the power switch 210 inserted into the power line between both microcomputers is turned on. As a result, the power supply voltage V _DD supplied to the sub-microcomputer 203 and the reset circuit 211 rises as shown in FIG. 4c. The output of the reset circuit 209 gradually rises with a predetermined time constant with respect to the power supply voltage c, as shown in _FIG .
Reset.

By controlling the power supply of the sub-microcomputer 203 by the host microcomputer 200 in this manner, it is possible to maintain synchronization between the two microcomputers 200 and 203. Here, considering the case where such a synchronization method is not adopted, both microcontrollers 200,
It is necessary to provide a dedicated synchronization line for synchronizing 203, which complicates the wiring structure and increases work time.

In addition, the reset circuit 209 on the host microcomputer side
can detect a momentary interruption in the power supply voltage, and as is clear from FIG. 4, even if there is a momentary interruption in the power supply voltage, the host microcomputer 200 and the sub-microcomputer 203 are reset at a fixed timing, making it possible to maintain synchronization between the two.

The host microcomputer 200 has a built-in address memory 212 and a backup memory 213, as shown in FIG. supply is becoming available. Backup power supply is resistor _R1
The voltage is regulated by the Zener diode ZD, and the sub microcomputer 203 and host microcomputer 200
The power is supplied to the power terminal of the host microcomputer 200 via the communication line 206 between them and the diode _D1 .

The play start switch 93 is a normally closed type switch, and as shown in FIG.
It is connected in series with a detection switch 103 that detects when a disk transport tray (not shown) within the housing 2 has reached its forward movement limit position, that is, when the disk has been transported to an eject position. One end of these switch series connection circuits is connected to the input end of the sub-microcomputer 203 and is connected to a resistor.
It is connected to the power supply V _DD via R ₂ and the other end is grounded. After the performance ends, when the disc is transported to the eject position, the detection switch 103 is closed, and a low level detection signal is supplied to the input terminal of the sub-microcomputer 203. On the other hand, when the disk is pushed slightly in the loading direction at the eject position, the play start switch 93 opens, and the input terminal of the sub-microcomputer 203, which was at a low level, changes to a high level, and it is detected that a replay command has been issued. be done.

A loading mechanism (disk transport means) 214 that transports the disc inserted from the slot 3a of the housing 2 (first illustration) to a performance position, and a pick-up moving mechanism 216 that moves the pick-up 215 in the radial direction of the disc include a host. Main power is supplied through a main power switch 217 that is on/off controlled by a microcomputer 200. When this player system is used in combination with another source source, such as a tape deck or tuner, the host microcomputer 200 controls the main input to the loading mechanism 214 and pickup moving mechanism 216 when another source is input during performance. Control is performed to turn off the main power switch 217 to stop the supply of power.

In FIG. 3, program information including address information is recorded on the disk 5, and this recorded information is read by a pickup 215. The information read by the pick-up 215 passes through a demodulation circuit 218, and address information is detected in an address determination circuit 219.
5's current position is determined. The latest address information is then stored in the address memory 212 within the host microcomputer 200. 220 is pick up 2
This is a focus detection circuit that constantly monitors whether the pickup is in focus based on the output of 15, and generates an output when it is out of focus. When the output of the focus detection circuit 220 is generated, the host microcomputer 200 outputs the pick-up 21.
5 is the home position (rest position before the performance starts)
The pickup moving mechanism 216 is driven and controlled to return to the home position, and the focus is again taken at the home position. After the focus is regained, the pickup 215 is moved to the previous address stored in the address memory 21 so as to start playing again from the address immediately before the focus was lost.

During the performance, the car accessory switch 20
When the main power of the system is cut off due to 7 being turned off,
The power-off detection circuit 221 detects this and generates an output. Upon generation of this detection output, the latest address information stored in the address memory 212 is written to the backup memory 213. When the main power is supplied again, the performance starts from the address written in the backup memory 213.

The host microcomputer 200 also performs a count operation at a fixed period during the performance to pick up the pick-up 2.
a counter 222 that sequentially outputs expected address information to which 15 should move next; and an address memory 212.
The host microcomputer 220 has a built-in detection circuit 223 that constantly compares the latest address information from the counter 222 with the expected address information from the counter 222 and generates an output when they do not match.
With an output of 3, it is determined that the information reading point of the pickup 215 following the recording track of the disk 5 has skipped over that track. When it is determined that the track has skipped, the pick-up moving mechanism 21 moves the information reading point of the pick-up 215 to the expected address according to the output of the counter 222.
6 is driven and controlled.

224 is a temperature sensing element such as a thermistor, and the first
It is provided within the housing 2 shown in the figure, preferably near the pickup 215. Temperature detection circuit 22
5 generates an output when the output of the temperature sensing element 224 exceeds a predetermined range, that is, when the temperature inside the housing 2 rises abnormally. This temperature detection circuit 2
The output of 25 is valid only when the disc is set in the playing position. That is, when the temperature detection circuit 225 generates an output during the operation period of the disk loading detection switch (not shown) that detects the completion of loading the disk to the performance position, the host microcomputer 200 switches the main power switch in FIG. 217 is turned off (opened) to stop supplying power to the mechanical section, and the temperature sensor 224 is placed in a standby state until the output of the temperature sensing element 224 falls within the predetermined range.
In addition to stopping the power supply, for example, the display section 202 is also used, and when the loading of the disk is completed, the display section 202 is switched to display the temperature, so that the temperature inside the housing 2 has risen abnormally. You can also give a warning.

When the disc 5 is inserted through the slot 3a of the housing 2, the disc 5 is transported by the loading mechanism 214 to the performance position. When the play start switch 6a of the operation button group 6 arranged on the front panel 3 is pressed,
Host microcomputer 20 shown in FIGS. 2 and 3
A play start command signal is issued from 0, the turntable rotates in response, and then the pick-up 215 is driven by the pick-up moving mechanism 216 to start moving from the home position to start playing (playback). . The home position of the pick-up 215 is set at a predetermined position within the information recording range of the disk, preferably near the innermost circumference position which is the recording start position.
5 reaches the home position, a pick-up detection switch (not shown) is activated.

When playing, in FIG. 5, it is first determined in step 1 whether or not the pick-up 215 is in the home position. If it is in the home position, the focus is placed on the pick-up 215 (step 2), and the Start a read operation. Then, in step 3, based on the address information obtained by the pick-up 215, the information recording start position, which is the lead-in area of the disk, ie, TOC (Table of Contents) is determined.
The position is calculated. The TOC records the number of songs recorded on the disc, the total absolute time, the playing time of each song, etc., and must be recorded before starting a performance.
It is necessary to read the recorded information of TOC. As a method of calculating the TOC position (target address) from the current address, for example,
-Using the method proposed in No. 201994, that is, the closer you get to the target address, the more accurate the distance to the target address can be obtained, the distance to the target is repeatedly calculated until the distance to the target address reaches a constant value. There is a way to calculate and move the pick-up.

When the TOC position is calculated in step 3, the pick-up 215 is moved to the corresponding position (step 4). And TOC by pick up 215
The content is read (step 5), and the next step is to move on to the performance operation. The closer the pick-up 215's home position is to the TOC position, the more quickly it can shift to the playing operation. Note that if it is determined in step 1 that the pick-up 215 is not at the home position, the pick-up moving mechanism 216
Movement to the home position is performed by (step 6).

In a normal performance operation, as shown in FIG. 6, an initial value of the expected address M is set in step 32, and then an error check is performed in step 33. If it is determined that there is an error, the number of error detections t is increased by 1 (t=t+1) in step 34, and if the number of detections t is determined to be smaller than the predetermined number of times x in step 35, the process moves to step 33. However, if it is determined that the predetermined number of times x has been reached, a stop state is entered. step 33
If it is determined that there is no error, the number of times t of error detection is reset (t=0) in step 36, and the address of the performance frame is read (step 37).

It is determined in step 38 whether this read address (latest address) N matches the expected address M, and if they do not match, it is determined that a track skip has occurred, and a so-called muting operation is turned on to cut off the audio output. Then, in step 40, the information reading point of the pickup 215 is jumped by (M-N) addresses, that is, to the expected address, and then the process proceeds to step 33. If it is determined in step 38 that the read address N matches the expected address M, and the muting operation has been on until then,
After canceling the muting operation (step 41), return to step 33. The above series of operations is repeated until the performance ends.

When the performance is finished, the pick-up moving mechanism 21
6 and the turntable are stopped, and at the same time, the loading mechanism 214 starts a reversing operation to eject the disc 5 from the slot 3a. In addition, the pick-up 215 also has a pick-up moving mechanism 216.
The robot is then returned to its home position.
In this way, the disk 5 is recovered.

Incidentally, when it is desired to play again the disc 5 which has been played once, the play start switch 93 shown in FIG. 2 is activated by slightly pushing the disc in the disc insertion direction, and the play is started again.

It should be noted that although the autoloading disk player is shown for use in a vehicle, it goes without saying that it can also be used indoors for home use.

Effects As explained above, according to the present invention, the counter is provided with a counter that counts at a constant cycle and outputs the expected address information in sequence, independently of the address information read by the pick-up, and the latest address read by the pick-up is The information is compared with the expected address information obtained by a constant cycle counting operation, and it is determined that a track jump has occurred due to a mismatch between the two address information, and the pick-up is moved to the expected address. A disk player can be obtained which can quickly and reliably detect a jump and can smoothly perform a subsequent return operation. In such a disk player, especially when a track jump occurs due to a dropout, the track jump will occur again even if the pick-up is returned to the original address, and this will be repeated. However, by using the above control method, This is useful because the playback operation can be performed smoothly.

[Brief explanation of the drawing]

FIG. 1 is a schematic perspective view showing the entire in-vehicle autoloading disk player according to the present invention, FIGS. 2 and 3 are block diagrams showing the control system, and FIG.
The figure is a waveform diagram of each part a to d in FIG. 2, and FIGS. 5 and 6 are flowcharts for explaining the operation of the control system shown in FIGS. 2 and 3. Explanation of symbols of main parts, 2...Housing, 2
b... Lid body, 3... Front panel, 3a... Slot, 5... Disk, 6... Operation button group,
6a...Play start switch, 93...Play start switch, 103...Detection switch,
200...Host microcomputer, 203...Sub microcomputer, 209, 211...Reset circuit, 212
... Address memory, 213 ... Backup memory, 214 ... Loading mechanism, 215 ...
Pickup, 220...Focus detection circuit,
224...Temperature sensing element.

Claims (1)

[Scope of utility model registration request] a pick-up for reading program information including address information from a disk on which the program information is recorded; a pick-up moving means for moving the pick-up in a radial direction of the disk;
a memory circuit that stores the latest address information read by the pick-up; a counter that counts independently of the address information read by the pick-up at a constant cycle and sequentially outputs expected address information; a detection circuit that detects a mismatch between address information and expected address information of the counter; and a control circuit that drives and controls the pickup moving means to move the pickup to the expected address according to the output of the counter when the output of the detection circuit is generated. A disc player characterized by comprising: