JP2797807B2 - Direction determination device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention discriminates a relative moving direction between a light spot and a track on an optical disc (hereinafter, referred to as "moving direction").
This is related to a direction discriminating apparatus.

[0002]

2. Description of the Related Art In recent years, optical discs have been applied in a wide range of fields, and especially in applications requiring random access such as karaoke, data files, and external storage of computers, high-speed access operations and data transfer are required. . Therefore, in a direction discriminating device required for pulling in tracking control, it is important to stably discriminate a direction even during a high-speed access operation and a high-speed rotation operation (high transfer rate).

A conventional direction discriminating apparatus is disclosed, for example, in Japanese Patent Application Laid-Open No. 51-117005.

Hereinafter, a conventional direction discriminating apparatus will be described. FIG. 5 shows a block diagram of this conventional direction discriminating apparatus. In FIG. 5, 1 is an optical disk on which information signals are recorded in a predetermined track form, 2 is a rotating means for rotating the optical disk 1, and 3 is a light spot formed by condensing a light beam on the information surface of the optical disk 1. An optical pickup that outputs a recorded information signal and a relative position error (hereinafter, abbreviated as a relative error) between a track and a light spot in a disk radial direction by detecting the reflected light;
4 is a tracking actuator for moving the optical pickup 3 in the radial direction of the disk, 5 is tracking driving means for driving the tracking actuator 4, 6 is a tracking error signal generating means for generating a tracking error signal from the output of the optical pickup 3, and 8 is tracking. Tracking control means 9 for performing tracking control with an error signal as an input, detects a relative movement direction between a light spot and a track by using the tracking error signal and a recording information signal output of the optical pickup 3 as inputs (hereinafter, abbreviated as direction detection). Direction detecting means, 12 is upper limit means for limiting the output of the tracking control means 8 with a positive constant value '+ a', and 13 is lower limit for lowering the output of the tracking control means 8 with a negative constant value '-a'. Limiting means, 1
Reference numeral 4 denotes second selection means for selecting either the output of the upper limit means 12 or the output of the lower limit means 13 according to the output of the direction detection means 9, and 15 the tracking control based on the output of the tracking error signal generation means 6. The tracking control settling detecting means 16 for detecting that the control signal is settled, and the tracking control settling detecting means 16 selects either the output of the second selecting means 14 or the output of the tracking control means 8 based on the output of the tracking control settling detecting means 15. 3 means of selection,
Reference numeral 17 denotes a tracking control loop opening / closing command generating means for generating a tracking control loop opening / closing command, and 18 selects either the output of the third selecting means 16 or the 0 level according to the output of the tracking control loop opening / closing command generating means 17. This is the fourth selection means to be performed.

[0005] The operation of the direction discriminating apparatus configured as described above will be described below.

When pulling in tracking control, first, the fourth selecting means 1 selects and outputs the 0 level.
8 is switched so as to select the output of the third selecting means 16 in response to a command from the tracking control loop opening / closing command generating means 17. That is, the tracking control loop is closed from the open state. In this tracking control loop, a relative error is detected by the optical pickup 3, this becomes a tracking error signal by the tracking error signal means 6, and the tracking control means 8 performs phase compensation for stabilizing the tracking control. When the tracking control loop is closed and the tracking control is not settled, the direction detecting means 9 detects the relative moving direction, and the second selecting means 14 determines whether the output of the upper limit means 12 is obtained by the second selecting means 14. The output of the lower limit means 13 is selected. The output of the second selector 14 is input to the tracking driver 5 through the third selector 16 and the fourth selector 18 to drive the tracking actuator 4. That is, when the light spot moves relatively from the inner circumference to the outer circumference, the upper limit is applied and only the driving force from the outer circumference to the inner circumference is applied. When the light spot moves relatively from the outer circumference to the inner circumference, the lower limit is applied. Only the driving force from the inner circumference to the outer circumference is applied. in this way,
Since the driving force is applied in the direction to stop the relative movement, the tracking control is easily settled. When the tracking control is settled, the limiter is released by the third selecting means 16, and the output of the tracking controlling means 8 is input to the tracking driving means 5 through the third selecting means 16 and the fourth selecting means 18, The tracking actuator 4 is driven to perform normal control. In this way, tracking control can be drawn.

Next, a specific operation of the direction detecting means 9 will be described. FIG. 6 is a block diagram of a conventional direction detecting means, FIG. 7 is a waveform diagram showing each waveform when the optical pickup moves relatively from the outer periphery to the inner periphery of the optical disk, and FIG. FIG. 7 is a waveform diagram showing waveforms when the optical pickup is moved.

In FIG. 6, reference numeral 31 denotes an envelope detection / binarization means for detecting an envelope of a recorded information signal, comparing the detected envelope with a predetermined value, and binarizing the detected information signal. , 32 are inputting the tracking error signal and binarizing it, and 33 are inputting the output of the envelope detection and binarizing means 31 as input and detecting the first edge detecting means. , 34 receive the output of the binarization means 32 as input and detect the second edge detection means, and 35 receive the output of the envelope detection / binarization means 31 as input and provide second edge detection means. A first D flip-flop which latches at the rising edge of the output of 34; and a second D flip-flop which latches at the rising edge of the output of the first edge detection means 33 with the output of the binarization means 32 as input. , 37 as inputs the output of the D flip-flop 35, a third D flip-flop which latches on the rising edge of the D flip-flop 36. In addition, A, C to G, and X to Z indicate respective signals in the waveform diagrams of FIGS.

7 and 8, the horizontal axis represents time, and the vertical axis represents voltage. A is a recorded information signal, B is an envelope detection signal that has detected the envelope of the recorded information signal A, C is a tracking error signal, and D is a signal obtained by comparing the envelope detection signal B with a predetermined value. Valued off-track signal,
E is a signal obtained by detecting the edge of the off-track signal D, F is a track cross signal obtained by binarizing the tracking error signal C, G is a signal obtained by detecting the edge of the track cross signal F, and X is the first D flip-flop 35. Output signal of Y
Is the output signal of the second D flip-flop 36, and Z is the third output signal.
, Ie, the output signal of the direction detecting means 9.

First, when the optical pickup moves relatively from the outer circumference to the inner circumference of the optical disk, the recorded information signal A and tracking error signal C are respectively converted into an envelope detection / binarization means 31 and a binarization means. By means 32, FIG.
The waveforms shown in FIGS. Then, in the first D flip-flop 35, the off-track signal D is latched at the rising edge of the signal G that has detected the edge of the track cross signal F, and has an output waveform as indicated by X in FIG. Further, in the second D flip-flop 36, the track cross signal F is latched at the rising edge of the signal E that has detected the edge of the off-track signal D, and has an output waveform as indicated by Y in FIG. From FIG. 7, the waveform of the output signal X of the first D flip-flop 35 is always at the 0 level at the rising edge of the output signal Y of the second D flip-flop 36. The signal Z is always at the 0 level. As described above, when the optical pickup relatively moves from the outer circumference to the inner circumference of the optical disk, the output Z of the direction detecting means 9 is output at the 0 level.

When the optical pickup moves relatively from the inner circumference to the outer circumference of the optical disk, the same consideration is given.
, The output signal Z of the third D flip-flop 37 is always at one level.

[0012]

However, in the above-described conventional configuration, when the relative speed of the track and the light spot in the disk radial direction (hereinafter, abbreviated as relative speed) is high,
The difference between the frequency of the recorded information signal itself and the frequency of its envelope becomes small, and the envelope cannot be detected correctly, so that the direction detecting means malfunctions.

The present invention solves the above-mentioned conventional problems, and always performs a correct direction determination irrespective of the relative speed, and performs a direction determination for stably performing track pull-in at the time of high-speed access and high-speed operation. It is intended to provide a device.

[0014]

In order to achieve this object, a direction discriminating apparatus according to the present invention comprises a relative speed detecting means which receives an output of an optical pickup as an input, and a relative moving direction which receives an output of the optical pickup as an input. Direction detection means and light spots are initialized before jump operation starts
Track jump means that moves in the radial direction of the disc in accordance with the jump direction, and selection means that selects a value corresponding to the output of the direction detection means and the jump direction in accordance with the output of the relative speed detection means.

[0015]

[0016]

According to the present invention, when the relative speed exceeds a certain value by the above-described configuration, the relative speed is initially set before the jump operation is started.
By outputting a value according to the preset jump direction as a direction discrimination signal, the correct direction discrimination is always performed regardless of the relative speed, and the track pull-in at the time of high-speed access and high-speed operation is performed stably. .

[0017]

An embodiment of the present invention will be described below with reference to the drawings. In addition, as a conventional technology, relative speed
If the value exceeds a certain value, the previous value held direction detection result
Is output as a direction discrimination signal.
This will be described as an embodiment, and then the features of the present invention will be described in a second embodiment.
As an example, a description will be given focusing on differences from the first embodiment.

FIG. 1 shows a first embodiment of the present invention, and is a block diagram of a direction discriminating apparatus for performing initial pull-in of tracking control. In FIG. 1, 1 is an optical disk on which information signals are recorded in a predetermined track form, 2 is a rotating means for rotating the optical disk 1, and 3 is a light spot formed by condensing a light beam on the information surface of the optical disk 1. By detecting the reflected light, an optical pickup for outputting a recorded information signal and a relative position error (hereinafter, abbreviated as a relative error) between the track and the optical spot in the disk radial direction, and the optical pickup 3 moves the optical pickup 3 to the disk radius. 5 is a tracking driving means for driving the tracking actuator 4, 6 is a tracking error signal generating means for generating a tracking error signal from the output of the optical pickup 3, and 7 is a relative speed from the output of the optical pickup 3. The relative speed detecting means 8 for detecting receives a tracking error signal as an input. Tracking control means for performing tracking control, 9 detects the direction of relative movement between the light spot and the track as input a recording information signal output of the tracking error signal and the optical pickup 3 (hereinafter, abbreviated as direction detection) direction detection means, 1
0 is a holding means for storing the newest output from the direction detecting means 9, and 11 is a first means for selecting either the output of the direction detecting means 9 or the output of the holding means 10 according to the output of the relative speed detecting means 7. Selection means 12, upper limit means 12 for upper-limit limiting the output of the tracking control means 8 with a positive constant value '+ a', and reference numeral 13, lower limit limit for lowering the output of the tracking control means 8 with a negative constant value '-a' Means 14 for selecting one of the output of the upper limit means 12 and the output of the lower limit means 13 according to the output of the first selection means 11;
5 is based on the output of the tracking error signal generation means 6
A tracking control settling detecting means 16 for detecting that the tracking control is settled, and selects one of the output of the second selecting means 14 and the output of the tracking control means 8 according to the output of the tracking control settling detecting means 15. The third selecting means 17 is a tracking control loop opening / closing command generating means for generating a tracking control loop opening / closing command, and the reference numeral 18 is the output of the tracking control loop opening / closing command generating means 17 and the output of the third selecting means 16 is set to 0.
This is a fourth selection means for selecting one of the levels.

The operation of the direction discriminating apparatus of the present embodiment configured as described above will be described below.

First, the fourth selecting means 18 which selects and outputs the 0 level is switched so as to select the output of the third selecting means 16 in response to a command from the tracking control loop opening / closing command generating means 17. That is, the tracking control loop is closed from the open state. Here, when the disk eccentricity is small, the relative speed before the pull-in of the tracking control is low, so the output of the relative speed detecting means 7 selects the output of the direction detecting means 9 by the first selecting means 11. Then, the method of limiting the output of the tracking control means 8 is switched in accordance with the output of the direction detecting means 9, that is, the direction discrimination signal, so as to drive in the direction in which the relative movement is stopped. This is the same as the conventional example. However, when the disk eccentricity is large, or when the disk rotation speed is high to increase the transfer rate, the relative speed before the pull-in of the tracking control is high. In this embodiment, the first selection means 11 selects the output of the holding means 10, that is, the direction detection result of which the previous value was held, based on the output of the relative speed detection means 7, and outputs this as a direction determination signal. About this behavior,
This will be described in detail with reference to FIG.

FIG. 3 shows the operation of the first embodiment of the present invention, and is a waveform chart showing waveforms when the optical pickup moves relatively from the outer circumference to the inner circumference of the optical disk. FIG.
In the graph, the horizontal axis represents time, and the vertical axis represents voltage. A is a recorded information signal, B is a tracking error signal,
C is a direction detection signal, D is a relative speed signal, E is an output signal of the first selection means, that is, a direction discrimination signal, and 'e' is a maximum value of the relative speed at which the value of the direction detection signal C is definitely correct. It is.

First, the relative speed detecting means 7 detects the actual relative speed from the output of the optical pickup 3. This detection method may be any method, but here, as an example, the zero cross time interval of the tracking error signal is measured.

Now, when the waveform of the relative speed is like D, while the value is larger than 'e', the direction detection signal does not detect the correct direction as shown by C. Therefore,
In such a case, data before the relative speed becomes 'e' is output as a direction determination signal. That is, the output of the holding means 10 is selected by the first selecting means 11. FIG.
In the case of, the direction detection signal indicates that the relative speed is'
Since the level was 0 until it exceeded e ', the 0 level was stored in the holding means 10, and when the relative speed exceeded' e ', the output of the holding means 10 was selected by the first selecting means 11, and The level is output. Usually, the relative speed is D
Since it changes continuously as shown in (1), there is no problem even if the previous value is held. This is because the relative speed always becomes smaller than 'e' before the direction of the speed changes.
In this case, the direction discrimination signal is always at the 0 level as indicated by E, and indicates a correct value.

As described above, according to this embodiment, the relative speed detecting means (7) for detecting the relative speed using the output of the optical pickup (3) as an input, and the relative movement using the output of the optical pickup (3) as an input. Direction detecting means (9) for detecting a direction, holding means (10) for storing the latest output from the direction detecting means (9), and direction detecting means (9) according to the output of the relative speed detecting means (7). ) And the output of the holding means (10) are provided with the selection means (11), so that the direction can always be correctly determined even if the rotation speed is high or the eccentricity is large and the relative speed is high. In addition, the initial pull-in operation of the tracking control can be stably performed.

FIG. 2 is a block diagram of a direction discriminating apparatus according to a second embodiment of the present invention, in which tracking control is performed after jumping to an arbitrary track. In the figure, reference numerals 1 to 9 and 12 to 16 are the same as those in the configuration of FIG. 1 is different from FIG. 1 in that an acceleration pulse generating means 19 for generating an acceleration pulse for performing a track jump is provided.
Track jump control means 20 for controlling a track jump, and fifth selection means 21 for selecting 0 level or 1 level based on the output of the track jump control means 20
The first selecting means 11 selects either the output of the direction detecting means 9 or the output of the fifth selecting means 21; and the fourth selecting means 18 selects the track jump controlling means 2
The point is that one of the output of the third selection means 16 and the acceleration pulse generation means 19 is selected by the output of 0.

The operation of the direction discriminating apparatus configured as described above will be described below. First, the output of the acceleration pulse generator 19 is selected by the fourth selector 18 in accordance with a command from the track jump controller 20. Then, the acceleration pulse is input to the tracking driving means 5, and the light spot jumps to a target track. When the light spot reaches the target track or the acceleration time reaches a certain time, the output of the third selecting means 16 is selected by the fourth selecting means 18 by the command of the track jump control means 20, and tracking is performed. Close the control loop.

Normally, if the tracking control loop is closed at such a timing, the relative speed is high and the direction detection malfunctions, so that the tracking control cannot be pulled in stably. However, in the present embodiment, it is possible to always pull in stably.
Hereinafter, this operation will be described in detail with reference to FIG.

FIG. 4 is a waveform chart showing the operation of the second embodiment of the present invention. In FIG. 4, the horizontal axis represents time, and the vertical axis represents voltage. J is an acceleration pulse, K is a signal representing the speed of the tracking actuator, T0 is the jump start time, T1 is the jump end time, and va is the speed of the tracking actuator at time T1.

Now, it is assumed that an acceleration pulse as shown in FIG. 4J is applied to the tracking actuator 4 through the tracking actuator driving means 5 at time T0.
The speed of the tracking actuator 4 at this time is as shown by K. Assuming that the velocity va of the tracking actuator 4 at the time T1 is sufficiently higher than the relative velocity due to the eccentricity of the disk, the relative velocity at the time T1 becomes almost va. Therefore, at the moment when the application of the acceleration pulse is completed and the tracking control loop is closed, it can be considered that the relative movement direction matches the jumping direction. Therefore, after the jump is completed and before the tracking control loop is closed, the direction is initially set by the fifth selecting means 21 in advance in the inner circumferential direction when jumping in the inner circumferential direction and in the outer circumferential direction when jumping in the outer circumferential direction. After the tracking pull-in is performed and the relative speed detecting means 7 detects that the relative speed has decreased, the direction detecting means 9 switches to the direction discrimination signal actually measured.

As described above, according to this embodiment, the relative speed detecting means (7) for detecting the relative speed by using the output of the optical pickup (3) as an input and the relative movement using the output of the optical pickup (3) as an input. A direction detecting means (9) for detecting a direction and a selecting means (11) for selecting one of an output of the direction detecting means (9) and a predetermined value according to an output of the relative speed detecting means (7) are provided. Thereby, even if the jump speed is high, the direction can always be correctly determined, and the pull-in operation of the tracking control can be stably performed. Also, the first
As compared with the embodiment, the configuration of the apparatus can be simplified by the amount of the elimination of the holding means.

In the first embodiment, the relative speed detecting means 7 measures the zero-crossing time interval of the tracking error signal, but the signal obtained by binarizing the envelope of the recorded information signal by comparing it with a predetermined value. For example, a method such as measuring the period of the data may be used.

In the second embodiment, the tracking control loop is closed after the application of the acceleration pulse. However, the track jump operation itself may be performed by any acceleration / deceleration method.

In the first and second embodiments, the direction detection is used for the pull-in of the tracking control. However, since the present invention is a direction discriminating apparatus, the present invention is not limited to the pull-in of the tracking control. It can be applied to various uses, such as discriminating a direction during a tracking jump.

The direction detecting method may be any method as long as the direction is detected based on information obtained from the optical pickup.

Each means in the first and second embodiments can be realized by any of hardware, software, analog processing, and digital processing.

[0036]

As described above, according to the present invention, the output of the direction detecting means and the output of the track jumping means are initialized in advance in accordance with the output of the relative speed detecting means by the selecting means .
Since a value is selected according to the jump direction , correct direction determination is always performed irrespective of the relative speed, and track pull-in can be performed stably during high-speed access and high-speed operation.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a direction discriminating apparatus according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a direction discriminating apparatus according to a second embodiment of the present invention.

FIG. 3 is a waveform chart showing the operation of the direction discriminating apparatus according to the first embodiment of the present invention.

FIG. 4 is a waveform chart showing the operation of the direction discriminating apparatus according to the second embodiment of the present invention.

FIG. 5 is a block diagram showing a configuration of a conventional direction discriminating apparatus.

FIG. 6 is a block diagram showing an internal configuration of a direction detecting means 9 in FIG.

FIG. 7 is a waveform chart showing the operation of the conventional direction discriminating apparatus.

FIG. 8 is a waveform chart showing the operation of the conventional direction discriminating apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Optical disk 2 Rotation means 3 Optical pickup 7 Relative speed detection means 9 Direction detection means 10 Hold means 11 First selection means 21 Fifth selection means

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G11B 7/08-7/095 G11B 21/08-21/10

Claims (1)

(57) [Claims] A rotating means for rotating an optical disk on which an information signal is recorded in a predetermined track form; a light beam being condensed on an information surface of the optical disk to form a light spot, and the reflected light is detected. An optical pickup that outputs the information signal and a relative position error between the track and the optical spot in the disk radial direction; a relative speed detection unit that receives an output of the optical pickup; and an output of the optical pickup. wherein the direction detecting means for detecting the relative movement direction between the light spot and the track advance first the light spot jump operation is started earlier as
A track jump means for moving the disk radial direction in response to the period setting the jump direction, the selection means in response to an output of said relative speed detecting means, for selecting a value corresponding to the output and the jump direction of the direction detection means Direction discriminating device provided with.