JPS6059543A - Jumping device of track - Google Patents

Abstract

PURPOSE:To stabilize track jump by braking a servomechanism until the periodical width of a reproducing information signal and a tracking error signal exceeds a prescribed time width, and then braking the servomechanism. CONSTITUTION:A detecting means detects that the periodical width of a reproducing information signal SC or a tracking error signal SD outputted from a signal surface of an optical recording medium exceeds the prescribed time width. A jump signal forming means AMP1 forms a jump signal SB consisting of a driving signal part (a) for jumping with a prescribed time width TA and a braking signal part (b) following the part (a) and to be ended on the basis of detection of the detectting means. A loop switching control means SW controls the switching of a tracking servo loop so as to brake the tracking servo after braking by the part (b) of the signal SB. Therefore, the servomechanism is braked effectively and sufficiently and stable track jumping can be attained without changing the number of tracks to be jumped.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a track jump device for, for example, an optical compact disc player, which moves the beam irradiation position li1 on the signal surface of an optical recording medium in large jumps across the track. be.

BACKGROUND TECHNOLOGY AND PROBLEMS Conventionally, for example, in an optical compact disc player,
When accessing the beginning of a song by jumping the beam irradiation position across the track, this is done by combining a 1 track jump, a 10 track jump, and a 100 track jump. However, since the 1-track jump and 10-track jump are performed by monitoring the tracking error signal, a fairly accurate jump movement is performed.
The 100-track jump, in which the beam irradiation position is moved in large jumps across tracks, has a problem in that accurate jump movement is not performed.

This is because the jump movement of 100 track jumps requires a drive signal portion ao with a constant time width for jumping and a constant time width for applying braking after the jump, as shown in Figure 1 (-). Braking signal part BO
This is because the jump signal is made up of the following. That is, as can be seen from the period width of the tracking error signal shown in FIG. Due to the braking by bo, the beam slows down. However, the speed at which the beam crosses the track immediately after the intersection after the braking by the braking signal part bO is For this reason, the speed of crossing the track immediately before the jump movement varies depending on the direction in which it crosses, such as the forward or backward direction.

For this purpose, following braking by the braking signal part bo of the jump signal, the tracking servo loop is activated as shown in FIG.
Servo braking is performed by controlling the opening and closing as shown in 0).

When the speed of the beam crossing the track is fast and the period rlJ of the tracking error signal is still short, the number of trunks to be jumped may be reduced due to the fact that the time to close the servo loop is short and the servo braking is not sufficiently applied. This is because the situation changes dramatically.

Purpose of the Invention The present invention was invented in view of the above-mentioned problems, and its purpose is to increase the number of tracks to be jumped in order to move the beam irradiation position across the tracks in large jumps. To provide a trunk jumping device that allows stable truck jumping without causing significant changes in trunk jumping.

SUMMARY OF THE INVENTION A track jump device according to the present invention is as described at the beginning.

(a) a detection means for detecting that the period width of the reproduced information signal or the tracking error signal from the signal surface of the optical recording medium exceeds a predetermined time width; A jump forming a jump signal consisting of a drive signal portion of a predetermined time width for causing the jump, and a braking signal portion for applying braking after the jump, which follows the drive signal portion and ends when detected by the detection means. and signal forming means.

(C) The present invention is characterized by comprising a jump control circuit having loop opening/closing control means for controlling opening/closing of a tracking servo loop so as to apply braking subsequent to braking by the braking signal portion of the jump signal.

As a result, when the beam irradiation position is moved in a large jump across the track, braking is applied by the braking signal portion of the jump signal until the period width of the reproduction information signal or tracking error signal exceeds a predetermined time width. After that, servo braking is applied by controlling the opening and closing of the tracking servo loop. Therefore, in combination with the fact that servo braking is applied sufficiently effectively, the number of tracks to be jumped does not vary widely, and stable track jumping can be performed.

Embodiment Next, a specific embodiment in which the track jump device according to the present invention is applied to an optical compact disc player will be explained with reference to the drawings. FIG. 2 is a circuit diagram of a jump control circuit. is.

A signal diagram of a compact disc (not shown), which is an example of an optical recording medium, has tracks formed of bit strings modulated by audio information in a concentric or spiral shape. Therefore, in order to move the irradiation position of the laser beam for bit reading, which is an example of a beam on the signal surface of the compact disc, by a large jump in the radial direction of the compact disc across the track, it is necessary to
100 track jump command signal S shown in Figure (A)
^ is formed by the microcomputer.

This 100 track jump command signal 5Aij1 is given as a set input to the first flip-flop circuit (FF1), and the Q output becomes a ``H'' signal on the 1+'' terminal side of the non-inverting differential amplifier (AMPI). is given.On the other hand,
Since the second flip-flop circuit (FF2) is in the reset state, the Q output of the aL'' signal is applied to the 6-'' terminal side of the differential amplifier (AMPI).

Next, 14 hours after the first flip-flop circuit (FFI) is set, the first counter circuit section (O
A pulse signal is output from OUNT I ) and is used as the reset input of the first flip-flop circuit (FF"I ) and also as the reset input of the second flip-flop circuit v6 (FF2) (7
) is given as a set input. And a differential amplifier (
The @L" signal is applied to the 1+" terminal side of AMPI, and the "lHI' signal is applied to the IP-" terminal side.

Furthermore, after that, the second counter circuit section (00UNT2
) outputs a pulse signal and applies it as a reset input to the second flip-flop circuit (FF2), and @T, w signals are applied to the 1-'' terminal side of the differential amplifier (AMPI).

Therefore, the output waveform of the differential amplifier (AMPI) is
A jump signal SB is formed as shown in FIG.
Continuing from c, the braking signal part 1w is comprised of a braking signal part 1w for applying braking after the jump which ends with the pulse signal of the second counter circuit part (OOUNT2). Then, the jump signal SB is amplified and phase compensated by a drive amplifier (AMP2), and then given to 1c, for example, a tracking coil (OOIL) of a two-axis drive device. This two-axis drive device is configured to drive an objective lens that focuses a laser beam onto a signal surface of a compact disc in a tracking direction and a focusing direction, which are directions across the tracks.

By the way, the tracking coil (O
OIL) to the jump signal Sa to the driving amplifier (AMP2).
), the objective lens is acceleratedly moved in the tracking direction by the drive signal part a, and the objective lens that has been acceleratedly moved is braked by the braking signal part a. .

As a result, the irradiation position of the laser beam on the signal surface of the compact disc is moved by a large jump across the track. By the way, by jumping, the reproduced information signal SC has a large output when the laser beam is located on the track, and a small output when the laser beam is between the tracks, as shown in FIG. 6 (0). Become. Further, the tracking error signal SD becomes OV when the laser beam is on the track and when it is between the tracks, as shown in FIG. 60.

By the way, the first counter circuit section (OOUN'l'
l) includes a count section (OOUNTl-a), a comparison section (OOUNTl-b), and a setting section (OOUNTl-b).
-c). Therefore, the Q output of the first flip-flop circuit (FF'1) is @H"
By becoming a signal, the clock signal SE is sent to the count section (OOTJNTI-a) through an AND circuit (AND).
is given as counting input. This count section (00I
The number of clock pulses is counted in JNT1-a) and the counted value is set in the setting section (OOUNTI-c).
When the comparison unit (OOU) matches the set value corresponding to the time,
The pulse signal is output from NTI-b). That is, after the first flip-flop (FF1) is set, the signal SA is applied as a reset input.

Further, the second counter circuit section (OOUNT2) similarly includes a count section (00UNT2-a) and a comparison section (00UNT2-a).
IJNT2-b) and setting section (COTINT2-c
). And the clock signal S,
is given to the counting section (OOUNT2-a) as a counting input. However, the count section (OOUNT2-
a), the second 71J tube °7CM7 circuit (l
The Q output of i'F2) becomes the @H" signal, so the comparator circuit (oavi) of the tracking error signal SD
-t' The etch signal sF whose waveform has been shaped as shown in FIG. This count section (OOTJNT2-a) is given as a reset input through (NANDI).
), the number of clock pulses is counted in the setting section (00
For example, 0.5 m- set to TJNT2-c)
When it matches the set value corresponding to 18 hours of ec, the pulse signal is output from the comparator (OOUNT2-b). Therefore, the braking signal portion of the jump signal SB ends when the period of the tracking error signal SD exceeds a certain time width. Note that the etch detection circuit section (EDGE) includes an RO time constant circuit ('rlVB1
) and an exclusive OR circuit (1i3XOR).

VC, when the reproduced information signal Sc shown in FIG. 6 (0) as described above, closes the tracking servo loop and
When the shaft drive device is operated, the objective lens is moved in a direction in which the output of the reproduced information signal Sc becomes larger. Therefore, in the portion A of the reproduction information signal Sc shown in FIG. 6 (01), the objective lens is moved in the direction opposite to the jump movement direction, and in the portion B, the objective lens is moved in the jump movement direction. When the loop is closed at part A, servo braking is applied to the objective lens that has been moved at an accelerated rate.

Thus, the reproduced information signal SC is given to the mirror detection circuit section (MIRROR) in order to obtain a servo braking control signal. This mirror detection circuit section (MI)[)R) detects the level change of the reproduced information signal Sc and detects the level change of the reproduction information signal Sc as shown in FIG.
The signal shown in is formed.

That is, the reproduced information signal 8C passes through the coupling capacitor (01) and then passes through the diodes (Dl) to (D6
) and output as two output signals. And the output of the diode (D6) is the capacitor (
C2) and resistors (R1) (Il12). The time constant of this integrating circuit is relatively large, so that the level of the reproduced information signal SC does not change much, and a reference voltage for comparison that automatically follows the level fluctuation of the reproduced information signal is formed. On the other hand, the output of the diode (Dl) is integrated by an integrating circuit consisting of a capacitor (06) and a resistor (R3). Since the time constant of this integrating circuit is small, level fluctuations in the reproduced information signal 8c appear as they are. The two signals are then compared in a comparator circuit (00M2) to form the signal shown in FIG. 6 (Q).

By the way, this signal is one NAND circuit (NANI)
2) is directly applied to the other NAND circuit (NAND3) after being inverted by the inverter circuit (INV1). Also, both of these NAND circuits (NAND2) (NAND3
) is given an etch signal sF. And the output of the NAND circuit (NANI)2)(NAND3) is
It is applied as a set input or reset input to an RS flip-flop circuit section (FF3) consisting of a pair of NAND circuits (NAND4 (NAND5)), and a servo braking control signal SG shown in FIG. 6H is formed. The "L" signal of the braking control signal SG is the reproduction information signal 8.
It corresponds to part A of c.

By the way, the servo braking control signal Sa is generated by a pair of cascade-connected NAND circuits (NAND6) (NAND7).
It is applied to the gate circuit section (GATE) consisting of. One of the NAND circuits (NAND6) VC has the Q outputs of the first and second flip-flop circuits (FPl) (FF2) through the OR circuit (OR) further R,
O time constant circuit ('I'I■2) and buffer amplifier (
AMP3) as a gate signal. Further, it is further applied as a gate signal to the other NAND circuit (NAND7) through an inverter circuit (INV2). Thus, the control signal SG for servo braking is delayed by the RO time constant circuit force, e.g.
During the time period 1I-c, the signal is applied to the switch (SW) as a switch drive signal through the gate circuit section (GA, TFi). A switch that opens and closes this tracking loop (
SW) turns ON with the @L” signal and closes the servo loop.

The 'H' signal turns it off and opens the servo loop.

Note that the first and second flip-flop circuits (
When the Q output of either FFI) (FF2) is an “H” signal, the OR circuit (OR), inverter circuit (INV2) and NAND circuit (NAND
7), the @H" signal is applied to the switch (SW), and the servo loop is opened. Therefore, the opening and closing of the tracking servo loop by the switch (SW) VC is as shown in FIG. It becomes like this.

Therefore, the braking is caused by the braking signal portion of the jump signal SB! Then, to apply the brake, turn the switch (SW) 0N- by 5QVc to control the servo brake.
The opening/closing control of the tracking servo loop is performed by switching the OFF state. Then, switch (SW) O
The servo loop is closed in response to the A part of the reproduced information signal SC by the N state, and the tracking error signal Sn is applied to the tracking coil (OOlL) through the drive amplifier (AM)'2) to maintain constant servo braking. The braking signal portion of the jump signal So is configured to end by detecting that the time has exceeded 1tCL.
The raw information signal SC may also be used.

Furthermore, in this example, the jump movement of the laser beam irradiation position was performed by moving the objective lens using a two-axis drive device, but it was also performed by swinging or moving the entire optical system including the objective lens. It's okay.

Effect of the invention The present invention has the following advantages.

In order to move the beam irradiation position across the track in a large jump, the speed at which the beam crosses the track during the period of the reproduction information signal or the tracking error signal is set to a predetermined value in order to move the beam irradiation position across the track in a large jump. The braking signal portion immediately applies the brakes until the vehicle speed drops below the vehicle speed. Then, after the beam crosses the track at a predetermined speed or less, the opening/closing control of the tracking servo loop (servo braking is applied sufficiently effectively), and the jump is activated. Track jumping can be performed stably without the number of tracks being changed drastically. 1-Microcontroller etc. 7. c-to QiL＼de/＼人76groovehq bill←μ
Ru

[Brief explanation of the drawing]

Figures 1(A) to (0 are signal waveform diagrams for explaining the background art of the present invention and its problems, Figures 2 and 6 fA
) to fI) are drawings for explaining a specific embodiment of the track jump device according to the present invention, in which FIG. 2 is a circuit diagram of a jump control circuit, and FIG. 6 (Al to (I)
are signal waveform diagrams of various parts in the circuit diagram of FIG. In addition, in the symbols used in the drawings, (AMPl)
・・・・・・・・・ Differential amplifier (OOUN'l"1
)...Track 4th counter circuit section (0(XJ
N'r2)... -11! NI-Connection 2nd counter circuit section (OOMI)... Song Comparator circuit (, F'F'l) (F'F2)... 1st
and second flip-flop circuit (FF5)...RS flip-flop circuit section (GATE)... river-gate circuit section (
INVl)...Song/Inverter circuit (IN'v2
)・River... Inverter circuit (MIRROFL)...
Song Mirror horizontal circuit section (NAND2)・・・・・・・・・
・ NAND circuit (NAND3)・・・・・・・・・ NAND circuit (OR)・・・・・・・・・・・・ OR circuit (TIIl)--RO time constant circuit (TIME2) -, . . . , RO time constant circuit. Agent Masaru Ueya Yoshio Tsune Toshiki Sugiura

Claims (1)

[Scope of Claims] In a track jump device that moves a beam irradiation position on a signal surface of an optical recording medium in large jumps across a track, (al, reproduced information signal or tracking error from the signal surface of the optical recording medium) a detection means for detecting that the period of the signal exceeds a predetermined time width;
and a braking signal portion for applying braking after the jump, which continues the drive signal portion and ends upon detection by the detection means. (C) A track jump device characterized by comprising a jump control circuit having loop opening/closing control means for controlling opening/closing of a tracking servo loop so as to apply braking subsequent to braking by the braking signal portion of the jump signal.