JPS6057549A - Detection for defective disk of dad player mounted on vehicle - Google Patents

Abstract

PURPOSE:To detect surely the defect of a disk on the way of reproducing by storing preliminarily the troubled quantity of a desired disk in accordance with the number of times of sound skip of a focus servo system and performing the detecting action of a defective disc if the number of times of sound skip of the prescribed disc in the next reproducing goes larger than the stored value by a prescribed allowable value. CONSTITUTION:An audio output is taken out from an optical system 12 through a demodulating amplifier 25, and the demodulated signal output has a sound skip signal due to a trouble of the surface of the disk, and this sound skip signal is stored in a buffer memory 28 through a sound skip detecting circuit 26. This first data is used as a reference and is compared with the number of times of sound skip in the next and following reproducing; and if the variance exceeds a prescribed allowable value, it is detected as a defect data. A comparator 34 is provided for the purpose of comparing the number of times of sound skip in the current reproducing in the buffer memory 28 with the first stored value in the second and following disk reproducing, and a signal is outputted to an alarm circuit 36 to perform a desired alarm action if the difference exceeds the allowable value.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for detecting a defective disk in a DAD player for a vehicle. The present invention relates to a method for detecting a defective disk in a DAC player that issues a warning as defective.

BACKGROUND TECHNOLOGY Digital audio discs (DADs) have advantages such as being able to obtain extremely good sound quality compared to conventional groove-type records or cassette tapes, and being able to access a desired location on the disc in a short time. Due to these characteristics, efforts have been made in recent years to develop and put into practical use a vehicle DAD player that can play the DAD inside a vehicle.

However, unlike ordinary household DAD players, the user of this J:Una vehicle DAD player is often the driver of the vehicle, and for this reason, the operation of the player is complicated. This may interfere with driving, and for this reason, it is recommended that CAD players for vehicles be able to start and stop playback with a simple operation.
It is important.

It is preferable that this operation tH1 also effectively acts on the selection of defective disks. That is, I)A
In D, any disturbance on the disc surface, such as scratches or dust, will significantly reduce the playback quality, so
c Defective disks can be reliably eliminated, r t'J, but in the case of DADs for vehicles, the storage conditions are relatively poor, and the frequency of occurrence of defective disks is high. It is difficult to prevent the occurrence of defective disks.

Therefore, in a DΔD player for a vehicle, it is desired to reliably predict and detect a defective disc during playback, and thereby issue a warning to improve storage conditions in the vehicle interior. is 1 in the same month,
It was common for users, especially drivers, to issue defective discs after the fact.

Purpose of the Invention The present invention has been devised in view of the above-mentioned conventional problems, and its purpose is to provide a system that does not require any operation on the part of the user.
To provide an improved method for detecting a defective disk in a DAD player for a vehicle, which reliably predicts a disk defect during playback and automatically warns the user of the defect to improve storage conditions.

Structure of the Invention In order to achieve the above objectives, the present invention provides the following features:)71--
In a DAD play V for a vehicle that controls the distance between the disk and the pickup to a predetermined value using the servo system, the failure m of the desired disk is stored in advance in the number of skips of the force servo system, and the next predetermined value is stored. The present invention is characterized in that a disc is detected as a defective disc when the number of sound skips on the disc is greater than the stored value by a predetermined value of +17.

Embodiment 1 Below is a diagram of 1. <Q of the present invention? A preferred embodiment will now be described.

FIG. 1 shows a focus servo system of a DAD player to which the method of the present invention is applied, in which a laser beam emitted from a laser diode 10 is focused onto a bit surface of a disk 14 via an optical system 12. be done.

A portion of the optical system 12 (hs+) outputs the distance between the pickup and the pin 1- as a signal 100, which is compared with the target 1+Q 102. These comparison values are extracted with feedback No. 8 from a focus driver, which will be described later, and then supplied to an error detector 16 to detect momentary focus errors. The focus error is amplified 2
! After being amplified to a predetermined magnitude at step i18, it is supplied as a focus drive signal to the focus driver 22 via the phase compensator 20, and the focus driver 22 moves the actuator 24 to adjust the focus of the G-11 beam.

Therefore, according to the focus servo system shown in FIG. 1, even if the distance between the disk 14 and the pickup varies by a factor of j: due to vehicle vibrations, the actuator 24 follows these vibrations and compensates for the vibrations. be able to.

A-
The demodulated signal output includes a skip signal due to a fault on the disk surface, and this skip signal is stored in a buffer memory 28 via a skip detection circuit 26.

Therefore, the contents stored in the buffer memory 28 indicate the number of failures in the disc currently being played.

As described above, in the present invention, the number of skips in the disc currently being played is stored in an arbitrarily selected memory at the time of the first playback, and the next time's sound is recorded based on this initial data. The feature is that when the number of jumps is compared with the initial value and the fluctuation at that time exceeds a predetermined tolerance value, it is detected as defective data.

In order to store the number of first skips, n memories 30 are provided in the apparatus shown in FIG. 1, and the stored value of the buffer memory 28 is stored in a predetermined memory 30.

A control circuit 32 is provided to control storage and readout of the buffer memory 28 and the plurality of memories 30. A control signal indicating whether this is the second or subsequent disc for which the number of skips has been recorded is input, and a predetermined control signal is output to each buffer memory 28, 30 based on this input signal.

A comparator 34 is provided to compare the number of skips currently being played in the buffer memory 28 with the first stored value when playing the disc for the second and subsequent times, and the comparator 34 includes a predetermined tolerance value. By this, it is determined whether or not the fluctuation range of the number of skips from the second time onwards exceeds the allowable value with respect to the initial value, and if such a allowable value is exceeded, a signal is sent to the alarm circuit 36. is output to perform the desired alarm action.

FIG. 2 shows a preferred embodiment of the method for detecting a defective disc according to the present invention, in which a predetermined detection operation is performed using the aforementioned first national disc.

Immediately after the device starts from star 1 and the disc is loaded, playback starts, and during this playback, the number of skips described above is stored, and the stored value is sequentially updated and stored in the buffer memory 28.

During such re-writing, if the user performs an eject operation, a predetermined termination operation consisting of stopping the device, ejecting the disk, and turning off the power is performed; however, if such eject operation is not performed, The apparatus determines whether the disc currently being played back is a recorded disc or not, and if it is an unrecorded disc, the above-mentioned skip count is repeated and the playback ends.

Then, as soon as the playback is completed, the control circuit 32 stores the number of skipped sounds during this playback in a predetermined memory 30.
Ru. The stored memory 30 simultaneously stores the disk numbers of the seven corresponding disks, and based on these disk numbers, the control circuit 32 arbitrarily stores the memory 30 corresponding to a desired disk.
It is possible to read the contents of

On the other hand, if the disc currently being played is a recorded disc, the control circuit 32 reads out the stored contents of a predetermined memory 30 based on the disc number, and compares this initial value with the comparator circuit 32.
At the same time, the skip values in the buffer memory 28 are sequentially supplied to the comparison circuit 34. Therefore, the comparator circuit 34 sequentially stores the number of skips, that is, the number of failures, of the disk currently being played back as the initial value, and sends a defective disk signal (if the storage condition remains Then, a signal indicating that it will become unusable sooner or later is outputted to the alarm circuit 36.

Therefore, it is possible to easily detect a change in the failure value for a disk in which failures have increased in subsequent storage conditions since the first time it was played back, and to issue a desired warning effect.

In the embodiment shown in FIG. 2, the playback itself can be continued after the warning is given by sound or lamp, but in the present invention, it is also preferable to perform the end operation of the player at the same time as the warning.

Further, in the present invention, the number of memories 30 is equal to the number of disks used, but it is also possible to sequentially erase the stored contents of the corresponding memory 30 for disks that no longer require defective determination. It is also possible to perform the determination according to the present invention only on a specific disc.

Detailed description of the invention: According to the present invention, obstacles that are relatively easy to play when stored in a vehicle can be automatically detected during playback without the need for special operations, and faithful reproduction can be achieved. If there is a possibility that the disc may not play properly, please play it immediately.
The ttl2 and IJI output functions are automatically performed, and it becomes possible to warn the user that the disc storage condition in the vehicle compartment has improved.

Therefore, it is possible to minimize the number of operations required by the user, especially the driver, and allow him or her to concentrate on driving the vehicle.

[Brief explanation of drawings]

FIG. 1 is a block circuit diagram showing an example of a control circuit including a focus servo system to which the method for detecting a defective disk according to the present invention is applied, and FIG. FIG. 3 is a flowchart diagram that does not represent a preferred embodiment; 14... Disk, 16... Error detector, 26... Skip detection circuit, 28... Buffer 7 memory, 30... Memory, 32... Control circuit, 3/I... Comparison 36...Alarm circuit. Agent: Patent attorney Kenji Yoshida (1 other person) Figure 1 Figure 2

Claims (1)

[Claims] (1) In a vehicle DAD player that uses a focus turbo system to control the interval between a disk and a pink-up to a predetermined value, the failure m of a desired disk is memorized in advance by the number of skips of the focus servo system, and A method for detecting a defective disk for a DAD player for a vehicle, characterized in that a defective disk is detected when the number of skips exceeds the stored value by a predetermined tolerance or more.