JPH07249251A - Device for detecting disk loading of optical disk player - Google Patents

Abstract

PURPOSE:To improve reliability of the disk loading detection by detecting the disk loading without using a mechanical switch. CONSTITUTION:An amplifier 16 inputs a drive signal (s) of a loading motor simultaneously when the loading of a disk 6 is started and amplifies the signal (s) to output it to an optical pickup 10, and lights and drives a laser light source, and drives an objective lens 10-1 to the closest position to the disk 6. A level comparator 12 compares an output level of a photodetector 10-2 receiving a reflected laser beam from the disk 6 with a reference level, and a fall differential circuit 14 differentiates the fall of the output of the level comparator 12. Further, an AND gate 15 outputs the output of the fall differential circuit 14 as a loading detection signal (e) only for a loading period of the disk 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disc mounting detector for detecting that a disc of an optical disc player has been mounted.

[0002]

2. Description of the Related Art As shown in FIG. 3, a conventional disk mounting apparatus for an optical disk player is equipped with a roller lever 2 for vertically moving a transfer roller 1 for transferring a disk tray (not shown) and a clamper 3. And a clamper arm 5 that is urged in the disc clamp direction by the elastic force of the pressure spring 4. There is. The roller lever 2 is rotated clockwise by a drive device (not shown) when the disc is loaded or ejected, and counterclockwise when the recorded contents of the disc are read out, that is, when the disc is played.

Therefore, when the disc is mounted, the roller lever 2 is rotated clockwise to the position shown in FIG. 3, and the disc tray on which the disc 6 is mounted is mounted on the transfer roller 1 by a loading motor (not shown). Transferred to the position. When transferred to the mounting position, the roller lever 2 is driven counterclockwise. Following the counterclockwise rotation of the roller lever 2, the clamper arm 5 is rotated clockwise by the elastic force of the pressure spring 4 to bring the clamper 3 into pressure contact with the transferred disk 6. By this pressure contact, the disk 6 is pressed against a turntable (not shown) and can be rotationally driven by the turntable. Further, the driving of the loading motor is stopped based on the timing when the disc 6 is transferred to the mounting position.

Here, the disc mounting detection is performed by the cooperation of the microswitch 7 and the control circuit 8. That is, by driving the roller lever 2 in the counterclockwise direction, the actuator of the micro switch 7 is pressed by the roller lever 2, and the contact point of the micro switch 7 is switched to the ON state. The ON output from the microswitch 7 which has been switched to the ON state is sent to the control circuit 8. The controller 8 which receives the ON output from the micro switch 7 detects that the disk 6 is mounted.

[0005]

However, according to the above-mentioned conventional disc mounting detection device of the optical disc player, the disc mounting detection is performed based on the output of a mechanical switch such as a micro switch, so that the disc mounting detection is performed. There is a problem that the contacts of the mechanical switch are damaged or deteriorated as the number of times increases.

It is an object of the present invention to provide a disc mounting detection device for an optical disc player with improved reliability of mounting detection.

[0007]

DISCLOSURE OF THE INVENTION A disc mounting detection device for an optical disc player according to the present invention is a drive for driving a laser light source of an optical pickup to be turned on at the same time as loading of a disc and driving an objective lens to a position closest to the disc. Means, a level comparator for comparing the output level of the photodetector receiving the reflected laser light from the disk with a reference level, a detection means for detecting the trailing edge of the output of the level comparator, and during the loading of the disk. And a gate means for sending the output of the detecting means, and the output of the gate means is used as a disc loading detection signal.

The disc mounting detection device of the optical disc player of the present invention comprises a driving means for driving the laser light source of the optical pickup to light up and driving the objective lens to the closest position of the disc simultaneously with the start of loading the disc, A level comparator that compares the output level of the photodetector that receives the reflected laser light with a reference level, a detection unit that detects the trailing edge of the output of the level comparator, and a delay unit that delays the output of the detection unit. Gate means for transmitting the output of the delay means only during the loading period of the disk, and the output of the gate means is used as a disk mounting detection signal.

[0009]

In the disc mounting detection device of the optical disc player of the present invention, the laser light source of the optical pickup is turned on at the same time as the loading of the disc is started, and the objective lens is driven to the closest position of the disc by the driving means for clamping. The disc is lowered to. On this way, when the disc position reaches the in-focus position, the output that becomes the maximum level is output from the photodetector, and this output level is compared with the reference level in the level comparator,
The trailing edge of the output from the level comparator is detected by the detecting means. The output of the detection means during the loading period of the disk is output from the gate means as the disk loading detection output. Therefore, the disc mounting detection can be detected without using a mechanical switch, and the reliability of the mounting detection is improved. Further, in this case, since the mounting is detected based on the reflected light from the disk 6, the detection reliability is improved.

Further, when the delay means for delaying the output of the detecting means is provided so that the output of the delay means is sent out from the gate means only during the loading period of the disc, the reliability is improved in the same manner as described above. Besides, the generation timing of the mounting detection signal can be delayed by the delay means.

[0011]

EXAMPLES The present invention will be described below with reference to examples. Figure 1
FIG. 1 is a block diagram showing a configuration of an embodiment of a disc mounting detection device of an optical disc player according to the present invention.

The disk mounting apparatus in this embodiment is shown in FIG.
A case similar to the conventional case shown in FIG. 1 is illustrated, and the description of the transfer roller 1, the roller lever 2, the clamper 3, the pressure spring 4, and the clamper arm 5 is omitted to avoid duplication.

Reference numeral 10 denotes an optical pickup, which includes a laser light source (not shown), an objective lens 10-1 for irradiating the disk 6 with a laser beam from the laser light source to focus on the information recording surface, and an optical lens from the disk 6. A photodetector 10-2 provided with four photodiodes arranged at the apexes of a square for receiving reflected light and converting it into an electric signal, and focusing for describing a relative distance between the objective lens 10-1 and the disk 6 later. A focusing actuator coil (not shown) that drives the objective lens 10-1 for controlling based on the error signal is provided.

The output from the photodetector of the optical pickup 10 is supplied to the preamplifier 11 for amplification. Preamplifier 11
Is an objective lens 10-1 for reflecting laser light from the disk 6.
The signal output from the photodetector 10-2 received via (the signal obtained by adding the outputs of the four photodiodes forming the photodetector), that is, the output from the photodetector 10-2 based on the main spot. The signal is amplified and sent to the digital signal processing circuit as the signal a, and is also output from the photodetector 10-2 based on the sub-spot (from the sum of the outputs of the two photodiodes at the positions of the diagonal line, the other diagonal line). The output obtained by subtracting the sum of the outputs of the two photodiodes at the position) is amplified and sent as a focusing error signal. The focusing error signal is supplied to the servo signal processing circuit 13, the servo signal processing circuit 13 performs phase compensation, and the signal is sent to the focusing actuator coil.

Here, the optical pickup 10, the preamplifier 11 and the servo signal processing circuit 13 are usually provided in the optical disc player regardless of the disc mounting detection.

The disk loading detection apparatus of this embodiment includes a level comparator 12 which receives a signal a as an input and compares the level of the signal a with a reference level d, and an output b of the level comparator 12 as an input. A falling differentiating circuit 14 for differentiating the falling of the output, a driving signal s of the loading motor, and a signal obtained by inverting the output of the falling differentiating circuit 14 are input, and the AND gate 15 sends out the output as a mounting detection signal e. And an amplifier 16 for amplifying the driving signal s of the loading motor and sending the output to the focusing actuator coil and sending it to the laser light source as a driving instruction signal for the laser light source.
Here, the loading motor is configured to rotate during the period in which the drive signal s is being sent, and stop when the drive signal s disappears.

When a disc loading instruction is issued, the roller lever 2 is located at the position shown in FIG. 1, and the driving signal s is supplied to the loading motor. Upon receiving the drive signal s, the loading motor rotates, and the disc tray on which the disc 6 is placed is transported to the mounting position through the transport roller 1. When transferred to the mounting position, the roller lever 2 is driven counterclockwise. Following the counterclockwise rotation of the roller lever 2, the clamper arm 5 is rotated clockwise by the elastic force of the pressure spring 4, and the clamper 3 is brought into pressure contact with the transferred disk 6. As described above, the disc 6 is brought into press contact with a turntable (not shown) by this press contact so that it can be rotationally driven by the turntable.

In this case, the driving signal s of the loading motor is amplified by the amplifier 16 and the amplifier 1
Upon receiving the output of 6, the laser light source is started to be turned on and the laser light emission is started. Further, in response to the output of the amplifier 16, the focusing actuator coil drives the objective lens 10-1 to the position closest to the disk surface, that is, to the top dead center. Further, the gate of the AND gate 15 is controlled to be opened by the driving signal s of the loading motor.

Further, when the disk 6 is lowered to press the turntable, the laser light source is already driven and emits light, and the objective lens 10-1 is lifted to the top dead center. , A position where the laser beam is focused by the objective lens 10-1 while the disk 6 descends and is pressed against the turntable.
That is, the disc 6 passes through the focal point position.

Therefore, the focusing error signal is output from the preamplifier 11 while the disk 6 descends and is pressed against the turntable. The signal a has a maximum level at the time when the disc 6 passes the in-focus position, and the level decreases as the disc 6 moves away from the in-focus position and moves downward, as shown in FIG. The waveform is as shown in. Therefore, the level comparator 12 outputs a high potential output as shown in FIG. 2B while the level of the signal a exceeds the reference level d.

The output from the level comparator 12 is fall-differentiated by the fall differentiating circuit 17, the pulse shown in FIG. 2C is sent from the fall differentiating circuit 14, and the AND gate 15 detects the mounting of the disk 6. Signal e
Is output. In this case, when the drive signal s of the loading motor is not supplied to the AND gate 15, the gate of the AND gate 15 is closed, so that the mounting detection is performed even if the output of the falling differential circuit 14 is generated. No signal e is sent out. Therefore, the mounting detection signal e is not output by the reflected light from the disk 6 during the performance period when the mounting is completed and the information of the disk 6 is being read.

In the above embodiment, the driving of the loading motor may be stopped by the output of the AND gate 15, that is, the disc mounting detection signal e.

In the above embodiment, the level of the signal a is maximum at the focus position of the disk 6, so the fall timing of the level comparator 12 is determined by the selection of the reference level d, and this fall is the mounting detection signal e. Is generated, the reference level d given to the level comparator 12
The generation timing of the mounting detection signal e can be temporally shifted by changing the level of. Further, instead of changing the level of the reference level d, the falling differentiation circuit 14
Delay circuit 17 for delaying the output of
The output of 7 may be supplied to the AND gate 15. Since the generation timing of the mounting detection signal e can be temporally adjusted in this manner, when the mounting detection signal e is used as the stop signal of the loading motor, it is easy and convenient to adjust the stop position of the disc tray. Is.

As described above, according to this embodiment, it is not necessary to use a mechanical switch, and the reliability of mounting detection is improved. Further, in this case, the laser light source is driven together with the driving of the loading motor, and the objective lens 10-
Since 1 is driven to the position closest to the disc 6, the mounting is detected based on the reflected light from the disc 6, so that the detection reliability is improved.

[0025]

As described above, according to the disc mounting detection device of the optical disc player of the present invention, the disc mounting detection can be detected without using a mechanical switch and is not deteriorated by the number of detections, and the mounting detection can be performed. It has the effect of improving reliability. Further, in this case, the mounting is detected based on the reflected light from the disk 6, so that the reliability of the detection is improved.

Further, when the delay means for delaying the output of the detecting means is provided so that the output of the delay means is sent out from the gate means only during the loading period of the disc, the reliability is improved as in the above case. In addition, there is an effect that the generation timing of the mounting detection signal can be delayed by the delay means.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of a disc mounting detection device of an optical disc player according to the present invention.

FIG. 2 is a timing chart for explaining the operation of an embodiment of the disc mounting detection device of the optical disc player according to the present invention.

FIG. 3 is a schematic diagram of a disc mounting device of an optical disc player.

[Explanation of symbols]

 6 Disc 10 Optical Pickup 10-1 Objective Lens 10-2 Photodetector 12 Level Comparator 14 Falling Differentiation Circuit 15 AND Gate 17 Delay Circuit e Mounting Detection Signal s Loading Motor Drive Signal

Claims (2)

[Claims] 1. A driving means for lighting and driving a laser light source of an optical pickup and driving an objective lens to the closest position of the disc at the same time when the loading of the disc is started, and a photodetector which receives a reflected laser beam from the disc. The gate includes a level comparator for comparing the output level with the reference level, a detecting means for detecting the trailing edge of the output of the level comparator, and a gate means for sending the output of the detecting means only during the loading period of the disc. A disc mounting detection device for an optical disc player, wherein the output of the means is a disc mounting detection signal. 2. A drive means for turning on and driving a laser light source of an optical pickup at the same time as the start of loading of a disc and driving an objective lens to a position closest to the disc, and a photodetector receiving a reflected laser beam from the disc. A level comparator for comparing the output level with a reference level, a detection means for detecting the trailing edge of the output of the level comparator, a delay means for delaying the output of the detection means, and a delay means for the delay means only during a disc loading period. A disc mounting detection device for an optical disc player, comprising: gate means for transmitting an output, wherein the output of the gate means is a disc mounting detection signal.