JPS63304430A - Moving direction detector for information read point of information recording disk player - Google Patents

Abstract

PURPOSE:To detect surely the moving direction of a read point by discriminating the relation of a phase of a tracking error signal in opposite phase depending on the information read point moving direction with respect to a mirror signal in response to the output envelope of a pickup. CONSTITUTION:If a track jump takes place at a read point S1, an RF signal is caused from a photoelectric conversion element 1 and after the envelope is detected, the level is compared with a prescribed level Vr by a comparator 12 and a low level signifies the read point in the track and high level represents the point in the between the tracks. A tracking error signal from the differential amplifier 4 is compared with a 0 potential by a comparator 5 to obtain a rectangular wave signal. The leading/ trailing is detected by the circuit 6 to obtain a short pulse. The pulse represents the 0 potential of the error signal and a mirror signal level is caused to the output Q of the DFF 11 at the point of time of pulse. A mirror latch signal and a rectangular signal are EX-ORed 13 and a detection signal is obtained via the LPF 14 an the inverter 15. The signals at high level, the read point shows the jumping state toward the outer circumference and in case of a low level, the jumping state toward the outer circumference and both detects clearly the state.

Description

TECHNICAL FIELD The present invention relates to an information recording disc player, and more particularly to a device for detecting the moving direction of an information reading point of a pickup during a track jump.

BACKGROUND ART In information recording disc players, a track jump is performed to jump over tracks on a disc during double speed playback, slow playback, or search mode. When reproducing information recorded on an information recording disk using a constant linear velocity force type, when moving the information reading point of the pick amplifier from the outer circumferential side of the disk to the inner circumferential side, the rotation of the spindle motor is accelerated, and the information is When the reading point is jumped from the inner circumferential side to the outer circumferential side of the disk, the rotation of the spindle motor is decelerated. When controlling the rotation speed of the spindle motor by changing the voltage applied to the spindle motor, a larger rotational torque is required when moving the information reading point from the outer circumferential side to the inner circumferential side. It is considered better for high-speed access to change the magnitude of the applied voltage according to the moving direction of the information reading point.

In addition, in players that play information recording discs with constant rotational speed and force, such as so-called CAV discs,
The gain of the RF (high frequency) signal processing system or the tracking error signal processing system may be controlled depending on the position of the information reading point in the disk radial direction. It is useful to know the direction of movement of.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an information reading point moving direction detecting device for detecting the moving direction of an information reading point in an information recording disc player.

The information reading point movement direction detecting device of the present invention changes according to the amount of deviation of the information reading point of the pickup in the disk radial direction with respect to the recording track of the disk, and the center position of the recording track and the center position between adjacent tracks is set as a reference. means for generating a tracking error signal as a level, and means for generating a mirror signal indicating whether the information reading point is within the trunk or between the trucks based on the envelope of the read high frequency signal output from the pickup; It is characterized by comprising a determining means for determining the moving direction according to the phase relationship between the tracking error signal and the mirror signal.

Embodiments Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

In the optical information reading point movement direction detection device which is an embodiment of the present invention shown in FIG. 1, there are three beam spots obtained by converging a laser beam, that is, an information reading spot S1 and When the spot S1 moves relative to the disk, a pair of preceding and following tracking information detection spots S2 and S3 are irradiated from a pickup (not shown) to the recording track T of the disk with the positional relationship shown in the figure. Ru. The reflected light from these beam spots enters photoelectric conversion elements 1 to 3 built into the pickup.

The photoelectric conversion element 1 is constituted by four mutually independent light-receiving elements arranged so as to be divided into four by two straight lines perpendicular to each other on the light-receiving surface, and the total output of these elements is the read RF multiplied signal.

Each output of the photoelectric conversion element 2.3 is supplied to a differential amplifier 4 to detect a difference in surface output, and this difference output becomes a tracking error signal.

This tracking error signal is supplied to a tracking servo system (not shown) and a zero cross comparator 5.
supplied to An edge detection circuit 6 is connected to the output of the zero cross comparator 5. The edge detection circuit 6 includes an EX-OR circuit 7 that takes the exclusive OR of the output signal of the zero cross comparator 5 and the ground level, and
A resistor 8a and a capacitor 8b connected to the output of the circuit 7
EX- which takes the exclusive OR of the LPF (low pass filter) 8 and the output signal of LPF 8 and the ground level.
OR circuit 9 and E which takes the exclusive OR of the output signal of zero cross comparator 5 and the output signal of EX-OR circuit 9.
It consists of an X-OR circuit 10. The signal output from the edge detection circuit 6 is the clock terminal C of the D flip-flop 11.
K is supplied.

On the other hand, after the envelope of the RF multiplied signal is detected by an envelope detection means (not shown), it is supplied to a comparator 12 and compared with a predetermined level Vr, and the comparison output becomes a mirror signal. The mirror signal indicates whether the information reading spot is located within a track or between tracks. This mirror signal is supplied to the input end of the D flip-flop 11.

An EX-OR circuit 13 is connected to the output terminal Q of the D flip-flop 11, and the EX-OR circuit 13 takes the logical sum of the output signal of the flip-flop 11 and the output signal of the zero-cross comparator 5. An LPF 14 including a resistor 14a and a capacitor 14b is connected to the output J of the EX-OR circuit 13. The output signal of LPF14 is sent to inverter 15
The information is then output as an information reading spot moving direction detection signal.

In this configuration, when the information reading spot S1 makes a track jump, an RF multiplied signal is generated from the photoelectric converter 1 as shown in FIG. 2(a). After the envelope of this RF multiplied signal is detected, it is compared with a predetermined level Vr in a comparator 12, resulting in a mirror signal consisting of high and low levels as shown in FIG. 2(b). A low level portion of the mirror signal indicates that the information reading spot is located approximately within the recording track of the disk, and a high level portion indicates that the information reading spot is approximately located between the recording tracks of the disk. On the other hand, from the differential amplifier 4, as shown in Fig. 2 (C)
As shown in the figure, a tracking error (No. 2 or 2) occurs. The tracking error signal is compared with the ground potential (OV) in the zero cross comparator 5, and when the tracking error signal is higher than the ground potential, it becomes high level, and when it is below the ground potential, it becomes low level. The rectangular wave signal that becomes the level is shown in Figure 2 (d).
obtained as shown in . The rising and falling edges of this rectangular wave signal are detected by the edge detection circuit 6 and become edge pulses with a short time width as shown in FIG. 2(e). The edge pulse indicates the ground potential point of the tracking error signal, and is supplied to the D flip-flop 11, and the mirror signal level at the point of generation of the edge pulse is generated at the output terminal Q (mirror) of the D flip-flop 11.

FWD (forward) jump state in which the information reading spot jumps from the inner circumference side to the outer circumference side of the disc;
REV that jumps from the outer side of the disc to the inner side
In the (reverse) jump state, Fig. 2(b),
As shown in (c), the phase of the tracking error signal differs by 1800 from the mirror signal. Therefore, in the FWD jump state, the mirror latch signal output from the D flip-flop 11 almost matches the rectangular wave signal output from the zero cross comparator 5, as shown in the FWD jump portion of FIG. 2(f). As a result, EX
- When the OR circuit 13 takes the exclusive OR of the mirror latch signal and the rectangular wave signal, the output level of the EX-OR circuit 13 becomes a low level, or the time of the rise and fall of each signal is slightly F in Figure 2 (g) for the error.
As shown in the WD jump portion, a high level pulse with a short time width is generated when the tracking error signal reaches the ground potential. Since this high level pulse is removed by the LPF 14, the output level of the LPF 14 becomes completely low level. Furthermore, this low level output is inverted by the inverter 15 provided for waveform shaping, so the output of the inverter 15 becomes a high level as shown in the FWD jump part in FIG. 2(h), and this high level is at the information reading spot. represents the FWD jump state in which the disk jumps from the inner circumference side to the outer circumference side.

On the other hand, in the REV jump state, as shown in the REV jump portion of FIG. 2(f), the mirror latch signal has a substantially opposite phase relationship with the rectangular wave signal output from the zero cross comparator 5. As a result, EX-OR circuit 13
When the exclusive OR of the mirror latch signal and the rectangular wave signal is taken, the output level of the EX-OR circuit 13 becomes a high level. Due to the small time error of , a low level pulse with a short duration occurs at the ground potential point of the tracking error signal, as shown in the REV jump portion of FIG. 2(g). Since this low level pulse is removed by the LPF 14, the output level of the LPF 14 becomes completely high level. Furthermore, this high level output is inverted by the inverter 15 provided for waveform shaping, so the output of the inverter 15 becomes a low level as shown in the REV jump part of FIG. This represents a REV jump state in which the reading spot jumps from the outer circumferential side of the disk to the inner circumferential side.

If the voltage applied to the spindle motor during trunk jump is controlled using the detection signal obtained by the information reading point moving direction detection device of the present invention, high-speed access becomes possible, especially in the case of a search.

As a drive circuit for such a spindle motor, for example, as shown in FIG. 3, a circuit consisting of an operational amplifier 21, an input resistor 22, offset resistors 23, 24, feedback resistors 25, 26, and a switch 27 is used. In this drive circuit, the switch 27 is turned on in response to a detection signal indicating an FWD jump, short-circuiting the feedback resistor 25, so that the voltage applied to the spindle motor output from the operational amplifier 21 becomes low during the FWD jump, and the switch 27
During the off-state REV jump, the applied voltage output from the operational amplifier 21 becomes higher on the negative side than during the FWD jump.

In the above embodiment, since the inverter 15 is provided to shape the waveform of the output No. 13 of the LPF 14, the high level output is changed to WF in the FWD jump state.
Although a low level output can be obtained in the REV jump state, the present invention is not limited to this, as long as the output level is different between the FWD jump state and the REW jump state.

Further, if the circuit determines whether the FWD jump state or the REV jump state is in the state based on the phase relationship with the tracking error signal, the circuit is not limited to the above-mentioned embodiment.
It may be configured to maintain and output the output level.

Effects of the Invention As described above, in the information reading point moving direction detecting device of the present invention, the phase of the tracking error signal is opposite to the mirror signal according to the read RF multiplied signal envelope depending on the information reading point moving direction. Since we determine the phase relationship,
The moving direction of the information reading point can be detected reliably.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing an embodiment of the present invention, FIG. 2 is a waveform diagram showing the operation of each part of the apparatus shown in FIG. 1, and FIG. 3 is a circuit diagram showing a spindle motor drive circuit. Explanation of symbols of main parts 1 to 3...Photoelectric conversion element 4...Operation amplifier 5...Zero cross comparator 6...Edge detection circuit 7.9, 10.13 ...EX-OR circuit 8.1
4...LPF

Claims (2)

[Claims] (1) An information reading point moving direction detecting device for detecting the moving direction of the information reading point of a pickup when the information reading point of a pickup makes a track jump in an information recording disc player, the information reading point moving direction detecting device detecting the moving direction of the information reading point of the pickup when the information reading point of the pickup makes a track jump. means for generating a tracking error signal that varies according to the amount of deviation in the disk radial direction and becomes a reference level at the center position of the recording track and at the center position between adjacent tracks; means for generating a mirror signal indicating whether the information reading point is within a track or between tracks based on an envelope; and determining the moving direction according to a phase relationship between the tracking error signal and the mirror signal. 1. An information reading point movement direction detecting device comprising: a determining means for detecting a moving direction of an information reading point. (2) The determining means determines that the moving direction is from the inner circumferential side to the outer circumferential side of the disk when the tracking error signal is delayed in phase by 90 degrees with respect to the mirror signal, and 2. The information reading point moving direction detecting device according to claim 1, which determines that the moving direction is from the outer circumferential side to the inner circumferential side of the disk when the tracking error signal has a 90° lead phase.