JPH01173438A - Track jump device - Google Patents

Abstract

PURPOSE:To switch control from track jump control to track follow-up control by switching the control from the track jump control to the track follow-up control after a timing means counts prescribed time when jump instruction is inputted. CONSTITUTION:When a driving controller 17 outputs the jump instruction to a control logic circuit 19 and starts a timer 20, the control logic circuit 19 turns a switch 11 off and the switch 12 on according to the leading edge of a binarization signal from a binarization circuit 18, and switches the control from the track follow-up control to the track jump control. Next, when the next leading edge of the binarization signal is inputted from the binarization circuit 18, or when the time-up signal of the timer 20 is inputted, the controller logic circuit 19 turns the switch 11 on and the switch 12 off. Thus, the control can be switched from the track jump control to the track follow-up control.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an l/rack jump device used in optical disk devices and the like.

2. Description of the Related Art In general, optical disk devices and the like include a semiconductor laser that outputs a beam, an objective lens that focuses the beam and irradiates it onto a recording medium such as an optical disk, and an objective lens that collects the reflected light of the beam from the recording medium. It has an optical pink amplifier equipped with elements etc. that receive light through it.

This optical pink-up objective lens can be minutely moved in the radial direction of the recording medium so that the beam follows tracks on the recording medium (tracking), or closely seeks or jumps between tracks.

FIG. 2 shows a track jump device in a conventional optical disk device.

In FIG. 2, a sinusoidal tracking error signal is obtained based on the difference between the target displacement and the actual displacement of the objective lens 26, and this tracking error signal is converted into two by the binarization circuit 28 as shown in the lower part of FIG. The control logic circuit 29 turns off the switch 21 and turns on the switch 22 in response to the rise of this binary signal and a jump command from the drive controller (D-C) 27 to perform track jump control (speed control). do, then 2
At the next rising edge of the value signal, the switch 21 is turned on and the switch 22 is turned off to perform trunk follow-up control.

In the above configuration, when controlling the beam to follow the track of the recording medium, the switch 21 is turned on and the switch 22 is turned off under the control of the control logic circuit 29. In this case, the tracking error signal is phase compensated. The signal is stabilized by the circuit 23 and input to the drive circuit 24 via the switch 21.

1 drive circuit 24, this tracking error signal is
The objective lens is minutely moved in the radial direction of the recording medium so that the beam follows the track of the recording medium.

On the other hand, when controlling the beam to jump between tracks on the recording medium, the switch 21 is turned off and the switch 22 is turned on under the control of the control logic circuit 29. In this case, the tracking error signal is detected by the speed detection circuit. 26 to obtain the actual relative velocity signal of the objective lens 26 to the track, and the difference between the target velocity signal and this actual velocity signal is input to the drive circuit 24 via the switch 22.

The drive circuit 24 controls the objective lens to move slightly in the radial direction of the recording medium so that this signal becomes rOJ, and as a result, the beam jumps between tracks on the recording medium.

Therefore, in the above conventional example, the track following control is switched to track jump control (speed control) by the rising edge of the binary signal of the tracking error signal and the jump command, and the beam reaches the target track at the next rising edge of the binary signal. It is possible to detect this and switch from track jump control to track following control.

Problems to be Solved by the Invention However, with the above-mentioned conventional truck jump device,
In order to switch from track jump control to track following control at the second rising edge of the binary signal of the tracking error signal, the objective lens decelerates due to disturbance etc. during track jump control, and the relative speed of the objective lens to the track becomes lower than that of the target track. If it becomes "0" just before,
There is a problem that the second rising edge of the binarized signal is not detected and the objective lens moves in the opposite direction to the direction of the target track, resulting in a longer time for the beam to access the target track.

In view of the above problems, the present invention provides a track jump device that can reliably switch from track jump control to track following control even when the second rise of the binary signal of the tracking error signal is not detected during track jump control. The purpose is to provide

Means for Solving the Problems In order to solve the above problems, the present invention provides a means for timing a predetermined time when a jump command is input, and when the jump command is input and the binarized signal rises. When switching from track following control to track jump control,
The track jump control is switched to the track following control when the next binary signal rises or when the timer measures a predetermined time.

According to the above-described structure, the objective lens decelerates due to disturbance etc. during track jump control, and the relative speed of the objective lens to the track becomes "o" just before the target track, and the second rising edge of the binarized signal occurs. Even if the jump command is not detected, the track jump control can be switched to the track following control after a predetermined period of time has elapsed by the timer after the jump command.

EXAMPLES Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of a track jump device according to the present invention.

In FIG. 1, 13 is a phase compensation circuit that stabilizes a sinusoidal tracking error signal caused by the difference between the target displacement and the actual displacement of the objective lens 16; A switch 14 that is turned on when controlling the object to follow the trunk of the object lens is a drive circuit that drives the objective lens so that the input signal becomes rOJ.

16 is a speed detection circuit for differentiating the tracking error signal and obtaining an actual relative speed signal with respect to the trunk of the objective lens 15; 12 is a speed detection circuit for differentiating the tracking error signal to obtain an actual relative speed signal with respect to the trunk of the objective lens 15; and 12, under the control of the control logic circuit 1e, the beam moves between tracks of the recording medium. This is a switch that is turned on when controlling the vehicle to jump, and in this case, the difference between the target speed signal and this actual speed signal is input to the drive circuit 14 via the switch 12. 17 is a track following A drive controller (DRC) outputs a jump command for switching from control to track jump control, 18 is a binarization circuit that binarizes a tracking error signal, and 19 controls switches 11 and 12 as described later. control logic circuit,
2o is a timer that measures a predetermined time (for example, 1 m5ec).

Next, the operation of the embodiment according to the above configuration will be explained.

In Fig. 1, when controlling the beam so that it follows the track of the recording medium, the control logic 1
9 turns the switch 11 on and the switch 12 off. In this case, the tracking error signal is stabilized by the phase compensation circuit 13 and input to the drive circuit 14 via the switch 11.

Therefore, 1. The drive circuit 14 moves the objective lens 14 minutely in the radial direction of the recording medium so that this tracking error signal becomes rOJ, and controls the beam so that it follows the track of the recording medium as a result.

Here, when the drive controller 17 outputs a jump command to the control logic circuit 19 and starts the timer 20, the control logic circuit 19 switches the switch
1 is turned off and switch 12 is turned on to switch from track following control to track jump control.

The tracking error signal is differentiated by the speed detection circuit 16 to obtain an actual speed signal, and the difference between the target speed signal and this actual speed signal is input to the drive circuit 14 via the switch 12. , the drive circuit 14 moves the objective lens 16 slightly in the radial direction of the recording medium so that this signal becomes "o", and controls the beam to jump between the tracks of the recording medium as a result.

Next, the controller logic circuit 19 turns on the switch 11 and turns off the switch 12 when the next rising edge of the binarized signal from the binarization circuit 18 is input or when the time-up signal of the timer 20 is input. to switch from track jump control to track following control.

Therefore, even if the objective lens 16 decelerates due to disturbance or the like during track jump control and the relative speed of the objective lens 16 to the track becomes "○" just before the target trunk, the switch from track jump control to track following control is reliably made. , the beam can access the target track.

As described in detail, the present invention provides a means for timing a predetermined time when a jump command is input, and when the jump command is input and the binarized signal rises, the track control is started from the track following control. Since the track jump control is switched to the track following control when the next binary signal rises or when the timer measures a predetermined time, the track jump control is switched to the track following control. Even if the objective lens decelerates and the relative speed of the objective lens to the track reaches rOJ just before the target track, and the second rising edge of the binary signal is not detected, the track jump control can be reliably changed to the track following control. Can be switched.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of a track jump device according to the present invention, and FIG. 2 is a block diagram showing a conventional track jump device. 11.12... Switch, 13... Phase compensation circuit,
14... Drive circuit, 15... Objective lens, 16...
Speed detection circuit, 17... Drive controller, 18
...binarization circuit, 19° control logic circuit, 20...timer.

Claims (1)

[Claims] means for driving an objective lens so that the beam follows a track on a recording medium based on a tracking error signal, and driving the objective lens so that the beam jumps between tracks on the recording medium based on a speed signal; means for timing a predetermined time when a jump command is input;
When the binary signal rises, the speed signal is input to the driving means, and when the next binary signal rises, or when the timer measures a predetermined time. and means for switching the tracking error signal to be input to the driving means.