JPS6240671A - Track jumping-over control circuit for disk reproducing device - Google Patents

Abstract

PURPOSE:To make the correct track jumping-over and the pulling-in to the track servo after the jumping-over easy by supplying the time constant circuit part included in the holding means at the reproducing condition of the disk to the phase compensating action of the tracking error signal. CONSTITUTION:The main laser beam irradiated and reflected to the disk is light-received by a main beam detector 11. In the vicinity of the detector 11, subbeam detectors 12 and 13 are provided, and the light-received subbeam is supplied to a tracking error signal generating circuit 14. In the usual disk reproducing condition, a switch 21 is turned on, a sample holding circuit 22 supplies a tracking error signal TE to an adder circuit 15 as it does. When the track jumping-over is requested, the switch 21 comes to be off, a pulse P from a kick pulse generating circuit 19 is supplied through a phase compensating circuit 16 and an amplifying driving circuit 17 to a tracking actuator coil 18 instead of a signal TE, and the jumping-over can be executed without fail and the servo pulling-in after that can be executed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a disc playback device such as a compact disc player, and particularly to an improvement in a track skip control circuit that enables accurate track skipping.

[Technical Background of the Invention] As is well known, in optical disc playback devices such as compact disc players and video disc players, a desired portion of an information signal recorded on a disc is reproduced. It has a so-called search function that allows you to search quickly. This search function is realized by using a predetermined kick pulse to move the objective lens, which is a pickup element built into an optical pickup for reading information signals recorded on the disc, in the radial direction of the disc, that is, in the tracking direction. It is something that will be done.

FIG. 4 shows such conventional track jumping/control means. That is, numeral 11 in the figure is a main beam detector, which receives a main laser beam that is irradiated onto the disk and reflected through an objective lens (not shown). This main beam detector 11 is
It is configured in a so-called 4-division format with four light-receiving areas a to d, and the signal output from each light-receiving area a to d is used to generate a focus error signal corresponding to the deviation from the focused position of the objective lens. , RF multiplied signal generation, etc.

Further, a pair of sub-beam detectors 12 and 13 are provided near the main beam detector 11. The sub-beam detectors 12 and 13 each receive a pair of sub-laser beams that are irradiated onto the disk through the objective lens and reflected.

The signals outputted from the sub-beam detectors 12 and 13 are respectively supplied to a tracking error signal generation circuit 14 and used to generate a tracking error signal TE corresponding to the track deviation of the objective lens. The tracking error signal TE generated by the tracking error signal generation circuit 14 is sent to the adder circuit 15. The signal is supplied via a phase compensation circuit 16 and an amplification drive circuit 7 to a tracking actuator coil 18 for moving the objective lens in the tracking direction.

Here, the kick pulse KP generated by the kick pulse generation circuit 19 is supplied to the addition circuit 15. However, under normal disc playback conditions,
Since the kick pulse KP is not generated, the tracking error signal TE is supplied as it is to the tracking actuator coil 1B via the compensation circuit IB and the amplification drive circuit 17, where it is controlled so that the objective lens follows the track. tracking servo is performed.

When track skipping is requested in the disc playback state as described above, first, the switch 20 is turned on.
The tracking error signal TE is no longer supplied to the adder circuit 15. Then, the kick pulse generation circuit 19 generates a kick pulse KP corresponding to the direction and distance to be jumped, and this kick pulse KP replaces the tracking error signal TE and drives the addition circuit 159, phase compensation circuit 16, and amplification. The signal is supplied via a circuit 17 to a tracking actuator coil 18, where the objective lens is moved in the direction of the target position.

[Problems of Background Art] However, the following problems occur in the conventional track skipping control means as described above.

That is, it is assumed that the objective lens is now being moved in the tracking direction by the tracking servo, as shown by the solid line in FIG. Note that in FIG. 5, line A indicates the position of the objective lens when the voltage applied to the tracking actuator coil 18 is at the "0" level. The position of the objective lens on this line A is the center within the movement range of the objective lens.

Here, if track skipping is requested at time T[, if we ignore the kick pulse KP, the tracking error signal TE will no longer be supplied to the adder circuit 15 when the switch 20 is turned on, so tracking When the voltage applied to the actuator coil 18 reaches the "0" level, the objective lens approaches the center position, that is, line A, due to the time constant of the phase compensation circuit 18 and the physical characteristics of the objective lens drive mechanism. A biasing force is applied to the

Therefore, a biasing force is applied to the objective lens to move it in eight directions along a line as shown by the dotted line in FIG. 5 from time Tl.

Here, considering the kick pulse KP, if a kick pulse KP is generated that moves the objective lens from the position shown at time T1 to the point I in FIG. This means that it is moved in one point direction against the urging force that moves it in eight directions.

Therefore, at time T2, when the generation of the kick pulse KP is stopped and the tracking servo is restored, the position of the objective lens becomes point ■ in Fig. 5, and the objective lens cannot reach the correct position (point 1). It is something that will disappear.

Also, suppose that, contrary to the above, a kick pulse KP is generated that moves the objective lens in the direction of line A from the position of the objective lens at time TI. Then, the objective lens receives a biasing force to move it in the direction of line A and a kick pulse K.
The movement force caused by P in the same direction is added, resulting in too much acceleration, so even if the generation of the kick pulse KP is stopped at time T2, the objective lens cannot be focused on the target position by the tracking servo. It is. For this reason, it is still impossible to bring the objective lens to the correct position.

[Object of the Invention] The present invention has been made in consideration of the above circumstances, and provides an extremely good disc that can perform accurate track jumping and also allows the pickup element to be easily drawn into the tracking servo after track jumping is completed. An object of the present invention is to provide a track skip control circuit for a playback device.

[Summary of the Invention] That is, the track skipping control circuit of the disc playback device according to the present invention controls the pickup element based on the tracking error signal in the disc playback state, and also controls the pickup element at the time when track skipping is requested. The level of the tracking error signal at is held, and the pickup element is controlled by a signal obtained by adding a kick pulse to the held tracking error signal, and furthermore, in the disc playback state, the time constant included in the holding means is By making the circuit part serve as a phase compensation function for the tracking error signal, accurate track jumping can be performed, and the pickup element can be easily pulled into the tracking servo after track jumping is completed. It is something.

[Embodiment of the Invention] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. In FIG. 1, the same parts as in FIG. 4 are indicated by the same symbols, and only the different parts will be explained here. That is, the difference from the conventional method is that a switch 21, a sample hold circuit 22 consisting of a resistor R1, a capacitor C1, and an operational amplifier OPl are interposed between the tracking error signal generation circuit 14 and the addition circuit 15. It is.

First, in a normal disc playback state, the switch 21 is in an on state, and the sample hold circuit 22 is in a sample state.

That is, in this sample state, the sample hold circuit 22 directs the tracking error signal TE output from the tracking error signal generation circuit 14 to the addition circuit 15 as it is.

In this case, the kick pulse generation circuit 19 generates a kick pulse K
Since P is not generated, the tracking error signal TE supplied to the adder circuit 15 is directly sent to the phase compensation circuit 1.
6, and thereafter stable tracking servo is performed.

In this case, the resistor R constituting the sample and hold circuit 22
A time constant circuit portion consisting of 1 and a capacitor CI is used as a part of the phase compensation circuit IG.

When track skipping is requested in the disc playback state as described above, first, the switch 21 is turned off.
The kick pulse generation circuit 19 generates a kick pulse KP corresponding to the direction and distance to be jumped. This kick pulse KP is the tracking error signal T.
In place of E, "two-note addition circuit 151 phase compensation circuit 16
The signal is supplied to the tracking actuator coil 18 via the amplification drive circuit 17, where the objective lens is moved in the direction of the target position.

In this case, it is assumed that the objective lens is moved in the tracking direction by the tracking servo, as shown by the solid line in FIG. Note that in FIG. 2, line A indicates the position of the objective lens when the voltage applied to the tracking actuator coil 18 is at the "0" level, as described above, and the position of the objective lens on line A is is the center within the movement range of the objective lens.

If track skipping is requested at time T3, if we ignore the kick pulse KP, the level of the tracking error signal TE at the time the switch 21 is turned off will change as the switch 21 is turned off. , as shown by the dotted line in FIG.
It will now be held at 2. Therefore, the objective lens remains in the position at time T3 when track skipping was requested.

That is, the objective lens is no longer moved in the direction of line A in FIG. 2 as in the conventional case.

Here, considering the kick pulse KP, the kick pulse KP moves the objective lens to point I in FIG. 2 at time T3.
If , the kick pulse KP is used only to move the objective lens held at the position at the time T3 mentioned above in one point direction. Therefore, at time T4, when the generation of the kick pulse KP is stopped and the tracking servo is restored, the objective lens position will be at the desired one point, and it will be possible to reach the correct position. be.

In addition, conversely to the above, if a kick pulse KP is generated that moves the objective lens in the direction of line A from the position of the objective lens at time T3, the objective lens is moved only by the force of movement in the direction of line A due to the kick pulse KP. When the kick pulse KP is stopped from being generated at time T4, the objective lens can be easily focused on the target position by the tracking servo.

Therefore, according to the configuration of the above embodiment, the sample and hold circuit 22 is used to hold the tracking error signal TE at the time when track skipping is requested, and the kick pulse KP is applied to the held tracking error signal TE. Since the objective lens is moved to the target position using a signal that is added to , the objective lens can be easily pulled into the tracking servo after track skipping is completed.

Furthermore, since the time constant circuit portion consisting of the resistor R1 and capacitor Ct that constitutes the sample and hold circuit 22 is used as part of the phase compensation circuit 16, the configuration can be simplified. .

FIG. 3 shows a modification of the above embodiment, in which the addition circuit 15 and the sample hold circuit 22 are integrated.
Furthermore, this is an attempt to further simplify the configuration.

In this case, under normal disc playback conditions, resistors R1 and R
2 and the capacitor CI are part of the phase compensation circuit 16. Further, in the track jumping state, the tracking error signal TE is held by the time constant of the resistor R1 and the capacitor CI, and at this time the kick pulse KP is supplied to the phase compensation circuit 16 with a gain of R4/R3.

In the above embodiment, an optical disk reproducing apparatus has been described, but the present invention is not limited to an optical type, and can of course be applied to, for example, a capacitance type disk reproducing apparatus.

It should be noted that the present invention is not limited to the above-mentioned embodiments, and can be implemented with various modifications without departing from the gist thereof.

[Effects of the Invention] Therefore, as detailed above, according to the present invention, accurate track jumping can be performed, and
l. It is possible to provide an extremely good track skip control circuit for a disc playback device that can easily pull the pickup element into the tracking servo after rack skip is completed.

[Brief explanation of the drawing]

1 and 2 are block circuit configuration diagrams and operation explanatory diagrams showing an embodiment of the track skip control circuit of a disc playback device according to the present invention, respectively, and FIGS. 1 and 2 are block diagrams showing a modification of the same embodiment. Circuit configuration diagram, Figures 4 and 5
The figures are a block circuit diagram showing a conventional track skipping control means and an explanatory diagram of its operation, respectively. 1.1... Main beam detector, 12.13...
・Sub beam detector, 14...Tracking error signal generation circuit, 15...Addition circuit, 16...Phase compensation circuit, 17...Amplification drive circuit, 18...Tracking actuator coil, 19...Kick Pulse generation circuit, 20... switch, 21... switch,
22...Sample hold circuit.

Claims (1)

[Claims] A pickup that reads information signals recorded on a disk via a pickup element supported movably in the tracking direction, and generates a tracking error signal corresponding to the track deviation of the pickup element based on the signal read by the pickup. a tracking error signal generating means for generating a tracking error signal; a driving means for driving the pickup element in the tracking direction based on a tracking error signal output from the tracking error signal generating means; a track skipping means for generating and supplying the kick pulse to the driving means instead of the tracking error signal,
holding means for guiding the tracking error signal to the driving means in a state in which the disc is being reproduced and holding the level of the tracking error signal at that time in a state in which the track skipping is requested; addition means for adding a kick pulse generated by the track skipping means to the tracking error signal and guiding it to the drive means; A track skip control circuit for a disc reproducing apparatus, characterized in that the track skip control circuit is adapted to perform a phase compensation function on the tracking error signal.