JPH04205822A - Information recording and reproduction device - Google Patents

Abstract

PURPOSE:To achieve a stable and accurate seek operation by selecting an output of a speed detection means with a selection means which receives a switching signal which is output by detecting a center of a positional fluctuation of an objective lens and then performing speed control so that a speed difference between a recording medium and the objective lens is equal to 0. CONSTITUTION:A selection circuit 19 which receives a switching signal of an operation circuit 17b switches to a speed signal of a differential circuit 18 and outputs to a tracking control circuit 21 through a switching circuit 20. Then, the tracking control circuit 21 controls speed of a holder 5 so that a speed of an objective lens 4 reaches 0. On the other hand, a sequence control circuit 22 instructs switching so that a tracking error signal(TES) of a reproduction circuit 14 is output from the switching circuit 20 after a certain amount of time after the switching signal is generated. Then, the tracking control circuit 21 is positioned at a beam spot of a main beam 31 to a target track according to TES and completes seek operation and at the same time maintains tracking control state where the track follows, thus enabling seek accuracy to be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an information recording/reproducing apparatus that is resistant to vibrations of an objective lens, always stable, and capable of accessing a target track in a short time.

[Prior Art] In recent years, instead of using a magnetic head, it has become possible to optically write information and read recorded information by focusing laser light and irradiating it onto a recording medium. Optical information recording and reproducing devices have been put into practical use.

In order to accurately record/reproduce information, this type of information recording/reproducing device uses focus control to control the focus of the optical spot of the objective lens, and the objective lens to follow the skew and eccentricity of the track. It is necessary to perform tracking control. The holder that fixes the objective lens is attached to the head carriage on which the optical head is mounted using wires and plate springs so that it can move freely in the direction of focus control and the direction of tracking control. It is maintained calmly.

For example, when performing a seek operation, the distance from the current track to the target track is calculated, and the head carriage is moved according to the calculated distance using a scale that allows the position of the head carriage to be detected as a reference. and,
After the head carriage is in a stationary state with respect to the scale after the movement is completed, the optical spot is turned on to the track directly below the objective lens, the track number is confirmed, and the seek operation is completed.

By the way, mechanisms for performing focus control and tracking control are performed by respective actuators. This actuator is composed of a coil provided on a holder that fixes the objective lens, and a permanent magnet provided outside the holder. The holder is driven by passing a current through the coil in an external magnetic field created by a permanent magnet, and focus control and tracking control are performed. These controls are based on the balance between the force that drives the holder and the force of the springs that support the holder, and the balance can easily be lost due to non-uniformity of the external magnetic field or non-uniformity of each spring. , unnecessary vibration is likely to occur in the holder.

Japanese Patent Publication No. 62-15933 discloses that an optical head is equipped with a position detector that can detect the position of the objective lens in the radial direction of the recording medium in order to prevent unnecessary vibrations from occurring in the holder when the head carriage accelerates or decelerates. What is installed inside is disclosed.

In this conventional example, the position of the objective lens detected by position detection is fed back to perform tracking control, thereby preventing harmful effects caused by unnecessary vibrations.

In other words, during the seek operation, the position detector detects the position so that the optical axis of the objective lens does not deviate from the center position, which is the balance point of the spring that holds the objective lens, due to the force associated with acceleration and deceleration of the head carriage. The position of the objective lens is controlled by feed-panking.

[Problems to be Solved by the Invention] However, since it is difficult to attach the position detector to a holder to which the objective lens is fixed and perform detection, it is placed on the Herad carriage side. Therefore, vibrations occur in the holder due to the force accompanying acceleration and deceleration of the head carriage. This tendency is particularly strong during a seek operation, and the vibration is not necessarily parallel to the optical axis of the objective lens, but may be a rolling movement like a pendulum or other complex vibrations. That is, the position of the objective lens detected by the position detector and the actual position of the objective lens do not correspond to one objective.

Therefore, in the conventional example, during a seek operation, the objective lens just before track-on shifts due to vibration and moves onto a track different from the target track, resulting in deterioration of seek accuracy. Also, the next track-on operation may be started while the objective lens is still vibrating.
There is a drawback that the seek operation is delayed by the time it takes for the vibration to settle down, or if there is large vibration, tracking may be lost.

The present invention has been made in view of the above circumstances, and is an information recording system that does not lose tracking even when vibration of the objective lens occurs due to seek operation, correctly on-tracks, and performs high-speed and stable seek operation. The aim is to provide remade products.

[Means and effects for solving the problem] In order to achieve the above-mentioned object, an information recording/reproducing apparatus according to the present invention includes a light source that emits light, and a light beam from the light source that is focused onto a recording medium. an optical head provided with an objective lens to form a light spot; a drive means for moving the optical head relative to a track on a recording medium; and a driving means for driving and controlling the objective lens to form a light spot into a track on the recording medium. An information recording and reproducing apparatus for recording/reproducing information, comprising a tracking means for determining a position above the recording medium, and a speed detecting means for detecting a relative speed between the recording medium and the objective lens;
a positional fluctuation detecting means for detecting a relative positional fluctuation between the recording medium and the objective lens, determining the center of the positional fluctuation, and outputting a switching signal at the center position; a selection means for switching so that an output signal from the speed detection means is output to the tracking means in order to control the speed of the objective lens when a switching force signal of the fluctuation detection means is output; After the switching means switches, an on-track operation for positioning the optical spot to the target track is started.

With this configuration, when the optical head is driven by the drive means during seek, the selection means receives the switching signal output by the position fluctuation detection means that detects the center of the position fluctuation of the objective lens, and the selection means receives the switching signal output from the speed detection means. Along with selecting the output,
The optical spot is positioned on the target track by controlling the speed through the tracking means so that the speed difference between the recording medium and the objective lens becomes zero.

[Example] Hereinafter, the present invention will be described in detail with reference to the drawings.

1 to 8 relate to one embodiment of the present invention, in which FIG. 1 is a schematic configuration diagram of an optical card information recording and reproducing device, FIG. 2 is an explanatory diagram showing a light spot on an optical card, and FIG. Figure 3 is a waveform diagram showing the relationship between the track on the optical card and the total light amount signal and tracking error signal as the relative position of the light spot changes, and Figure 4 shows the relative position change in the opposite direction to Figure 3. 5 is a waveform diagram showing the relationship between the total light amount signal and the binarized total light amount signal, FIG. 6 is a schematic configuration diagram of the switching signal generation circuit, and FIG. 7 is a waveform diagram showing the relationship between the total light amount signal and the binarized total light amount signal. An explanatory diagram showing the operation of the up/down counter of the signal generation circuit,
FIG. 8 is an explanatory diagram showing the operation of the switching signal generation circuit.

An optical card information recording/reproducing apparatus 1 as an information recording/reproducing apparatus shown in FIG. 1 records/reproduces information onto/from an optical card 2 as a recording medium.

The optical card 2 shown in FIG. 2 has a plurality of recording tracks 2a on which data is recorded and guide tracks 2b that serve as tracking guides, and a main beam 31 and a sub-beam 32° from an optical head, which will be described later. 33 is irradiated. The reflected light of the main beam 31 becomes a total light amount signal, which will be described later, and the difference between the reflected lights of the sub beams 32 and 33 becomes a tracking error signal, which will be described later. Further, in the figure, C is the center of tracking, and the tracking error signal indicates a relative deviation between the center of the main beam 31 and the tracking center C, and the center of the main beam 31 coincides with the tracking center C. At this time, the total light amount signal becomes maximum.

The optical card information recording and reproducing device 1 includes an optical radar 3 for irradiating a light spot 2 with a light spot and reading recorded information.

The optical head 3 includes a light source (not shown), an objective lens 4 that collects light from the light source, a holder 5 that fixes the objective lens, and a head carriage 6 that holds the holter 5 using, for example, four wires 6a. a position detection member 7 fixed to the holder 5 in the head carriage 6; a position detector 8 fixed in the head carriage 6 and detecting the position of the objective lens 4 by a change in the position of the position detection member 7; An optical detector 9 is fixed within the head carriage 6 and detects reflected light from the optical card 2.

The optical card information recording/reproducing device 1 also includes a voice coil motor (hereinafter abbreviated as VCM) 10 that drives the optical head 3, a linear scale 11 that detects the position of VCMl(1), and a position of VCMIO. It is provided with a VCM control circuit 12 as a controlling driving means, and a phase compensation circuit 13 for compensating the output phase of the position detector 8.

Furthermore, the optical card information recording/reproducing device 1 includes a reproducing port 1114 that generates a total light amount signal, a tracking error signal (hereinafter abbreviated as TES), and a focus error signal (not shown) from the output of the optical detector 9. , a first binarization circuit 15 that binarizes the total light amount signal, a second binarization circuit 16 that binarizes the TES, and a VCMIO based on the binarized total light amount signal and TBS. a switching signal generation circuit 17 as a position fluctuation detection means that detects vibrations in the tracking direction between the optical card 2 and the objective lens 4 after the movement of the optical card 2 and the objective lens 4 is completed, and outputs a switching signal when the amount of displacement is zero; A differential circuit 18 as a speed detection means detects the relative moving speed of the optical card 2 and the objective lens 4 by the TBS of the reproduction circuit 14, and the phase compensation is performed according to the switching signal of the switching signal generation circuit 17. One selection circuit is provided as selection means for switching the output of the circuit 13 or the output of the differentiating circuit 18.

Furthermore, the optical card information recording/reproducing device 1 operates a selection circuit 1 according to an instruction from a sequence control circuit to be described later.
A switching circuit 20 that switches and outputs either the output signal of 9 or the TES of the reproducing circuit 14, and the lens of the phase compensation circuit 13 that is in the initial stage of the seek operation and is connected to the lens of the phase compensation circuit 13 via the switching circuit 19 of FIG. a tracking control circuit 21 that controls the position of the holder 5 based on a position signal;
Switching of the switching circuit 20 and the VCM control circuit 1
2, and a sequence control circuit 22 that performs various types of control.

When the selection circuit 19 outputs a switching signal from the switching signal generation circuit 17 during a seek, the selection circuit 19 selects a differential output from the phase compensation circuit 13. ! Outputs 818 and differentiates circuit 1
The tracking control circuit 21 controls the holder 5 based on the speed signal 8, and decelerates the holder 5 so that the objective lens 4 changes from a vibrating state to a stationary state. Further, the switching circuit 20 receives an instruction signal from the sequence control circuit 22 when the objective lens 4 is in a stationary state, and performs an on-track operation using the TBS. That is, during seek, the tracking control circuit 21 first performs position control based on the lens position signal from the phase compensation circuit 13, and then adjusts the velocity of the differential aperture N18 at the center position of the amount of variation of the vibrating objective lens 4. Speed control is performed by signals, and on-track operation is performed in a state where the objective lens 4 does not vibrate.

In response to instructions from the sequence control circuit 22, the VCM control circuit 12 controls the output of the tracking control circuit 21, which inputs the TBS of the regeneration circuit 14 through the switch 12a during read/write, to hold it with the wire 6a. VCMIO so that the objective lens 4 is at the center position.
It is designed to control the position of. Also, at the time of seek, the CM control circuit 12 inputs the output signal of the linear scale 11 via the switch 12a, and
It is designed to control the position of.

As shown in FIG. 6, the switching signal generation circuit 17 inputs the total light amount signal binarized by the first binarization circuit 15 to a clock terminal, and the second binarization circuit 1
6 up/down control the binarized TBS (U
/D) terminal, the up-down counter 17a performs up-counting and down-counting, and the median value of the maximum and minimum count outputs of the up-down counter 17a is determined, and the vibration of the objective lens 4 is determined. and an arithmetic circuit 17b that outputs a switching signal to one of the selection circuits when the central value is reached.

When the IJ/D terminal is "H", the up/down counter 17a counts down in synchronization with the rising edge of TBS input to the clock terminal, and the U/D terminal is "H".
When the uptown counter 17a is reset (R), the uptown counter 17a is reset (R
) terminal is configured to set the counter output to zero in response to a reset signal "L" from the sequence control circuit 22.

The operation of this embodiment will be described below with reference to the drawings.

During the seek operation, based on the VCMIO position signal detected by the linear scale 11, ■CM control circuit 1
2 drives and accelerates VCMIO to move the objective lens 4 to the target track.

At the same time, the holder 5 connects the position detection member 7, the position detector 8, and the phase compensation circuit 1 so that the output of the position detector 8 becomes zero.
3. The position is controlled by a loop consisting of one selection circuit, the switching circuit 20, and the tracking control circuit 12. Therefore, the holder 5 is moved so that the objective lens 4, which is held by the wire 6a, is always maintained at the center position.

However, the holder 5 may vibrate due to the rapid acceleration operation of the VCMIO. This is particularly noticeable when performing a high-speed seek operation to shorten access time.

At this time, in the apparatus of the embodiment, the holder 5 is switched from position control to speed control. Its operation will be described below.

The broken lines in FIGS. 3 and 4 indicate the relationship between the total light amount signal output from the reproduction circuit 14 and TES when the objective lens 4 has completed moving to the tracking center C position in FIG. 2 due to the seek operation. It shows. Also, the solid line in the same figure is
The relationship is shown in a state where the objective lens 4 is vibrating after the movement of the objective lens 4 is completed. And Figure 3 shows I.
The objective lens 4 is moving (vibrating) in the direction a in Fig. 1 with respect to the center C, and the total light intensity signal in Fig. 1(a) is different from the TES in Fig. 1(b). This shows that the phase advances. In addition, FIG. 4 shows a state in which the objective lens 4 is moving (vibrating) in the b direction in FIG. 1 with respect to the track center C, and the total light amount signal in FIG. T of
This shows that the phase lags behind the ES.

The first binarization circuit 15 becomes "H" when the total light amount signal shown in FIG. 5(a) is higher than the internally set comparator level, and becomes "L" when Figure 5 (
The resulting binary signal is shown in b).

Further, the second binarization circuit 16 similarly binarizes the TBS.

When the objective lens 4 is moving (vibrating) in the direction a in FIG. 1, the binarized total light amount signal and TBS have the relationship shown in FIG.
When the D terminal is always low, the up/down counter 1
At the clock terminal 7a, a binary total light amount signal rises. Therefore, the output of the up/down counter 17a continues to count up. Further, when the objective lens 4 is moving in the b direction in FIG. 1 (G movement), the output of the up/down counter 17a counts down.

FIG. 7 shows that after the movement of VCMIO is completed, the objective lens;
The figure illustrates the relationship between the amount of positional displacement of the objective lens 4 and the count output of the up/down counter 17a in a state where the lens is vibrating. Note that the horizontal axis is the time axis.

d in FIG. 7 is the time when the VCMIO movement is completed, e in FIG. 7 is the time when the arithmetic circuit 17b detects the maximum value (for example, 3), and f in FIG. (For example, -9) is detected. The arithmetic circuit 17b is
At time g in FIG. 7, the arithmetic circuit 17b outputs the maximum value (3
) and the minimum value (=9), and at the same time a switching signal is output to the selection circuit 19 and the sequence control circuit 22.

Since the up/down counter 17a counts at the rising edge of the signal, no matter which direction the objective lens 4 moves in the a direction or the b direction in FIG. The spot will be located in front of the tracking center C shown in FIG. Therefore, when the arithmetic circuit 17b outputs a switching signal (g in FIG. 7), it is always a period in which the light spot of the main beam 31 enters the target track 2a and heads toward the tracking center C. , this is the best timing to start decelerating the objective lens 4 in order to track the target track 2.

In the device of this embodiment, the selection circuit 19 receives the switching signal from the arithmetic circuit 17b, switches it to the speed signal from the differentiating circuit 18, and outputs it to the tracking control circuit 21 via the switching circuit 2o. The tracking control circuit 21 controls the speed of the holder 5 so that the speed of the objective lens 4 becomes zero.

On the other hand, the sequence control circuit 22 that receives the switching signal from the arithmetic circuit 17b executes (
At time h in FIG. 7), switching is instructed so that the TBS of the reproduction circuit 14 is output from the switching circuit 20. Then, the tracking control circuit 21 completes the seek operation by positioning the optical spot of the main beam 31 to the target track according to the TBS, and maintains the tracking control state of following the track.

Incidentally, during read/write, the holder 5 is driven and tracking control is performed according to the output of the tracking control circuit 21 which inputs the TBS of the reproducing circuit 14, and the output of the tracking control circuit 21 is used to control the output through the switch 12a. VCMIO to maintain the center position of objective lens 4.
The position of the head carriage 6 is controlled by.

Further, in the apparatus of this embodiment, the head carriage 6 is moved while the optical card 2 is stationary, and then the optical card 2 is moved again to confirm the target track.

For example, during seek, from the position control state of the objective lens 4 based on the lens position signal from the position detector 8, the optical path of the main beam 31 is adjusted to
The arithmetic circuit 17b outputs a switching signal at the timing when the object enters and moves toward the tracking center C, and the speed of the objective lens 4 is controlled by the speed signal of the differential circuit 18 to stop the vibration of the objective lens 4. I can do it. Furthermore, the sequence control circuit 22 can position the light spot on the target track 2 at the timing when the objective lens 4 is stationary after the movement of the head carriage 6 is completed.

Therefore, immediately before track-on, the objective lens is stationary, and it is possible to prevent the objective lens from moving onto a track different from the target track, thereby improving seek accuracy. Further, even if the next track-on operation is started while the objective lens is in a vibrated state, or even if the objective lens is subject to large vibrations, it is possible to prevent tracking failure.

Furthermore, compared to the case where the vibration of the objective lens 4 naturally settles down, the access time can be shortened because the speed is controlled so that the vibration of the objective lens 4 becomes zero.

In this embodiment, a device using an optical card as a recording medium is exemplified, but an information recording/reproducing device such as an optical disk or a magneto-optical disk may also be used.

Furthermore, the present invention can be applied to any information recording/reproducing apparatus of read-only type, write-once type, or rewritable type.

[Effects of the Invention] As described above, according to the information recording and reproducing apparatus of the present invention, when the optical head is driven by the drive means during seek, the position fluctuation detection means detects the center of the position fluctuation of the objective lens. The selection means that receives the switching signal outputted by
In addition to selecting the output of the speed detection means, the speed is controlled via the tracking means so that the speed difference between the recording medium and the objective lens becomes zero, and the light spot is positioned on the target track, so that the light spot is positioned on the target track immediately before the track is on. Due to the deviation of the vibration of the objective lens, it is possible to prevent on-tracking to a track different from the target track, and even when the vibration of the objective lens is large, tracking will not be lost, allowing stable and accurate seek operation. This has the effect of shortening access time.

[Brief explanation of the drawing]

1 to 8 relate to one embodiment of the present invention, in which FIG. 1 is a schematic configuration diagram of an optical card information recording and reproducing device, FIG. 2 is an explanatory diagram showing a light spot on an optical cart, and FIG. Figure 3 is a waveform diagram showing the relationship between the track on the optical card and the total light amount signal and tracking error signal as the relative position of the light spot changes, and Figure 4 shows the relative position change in the opposite direction to Figure 3. 5 is a waveform diagram showing the relationship between the total light amount signal and the binarized total light amount signal, FIG. 6 is a schematic configuration diagram of the switching signal generation circuit, and FIG. 7 is a waveform diagram showing the relationship between the total light amount signal and the binarized total light amount signal. An explanatory diagram showing the operation of the up/down counter of the signal generation circuit,
FIG. 8 is an explanatory diagram showing the operation of the switching signal generation circuit. 1... Optical card information recording/reproducing device 2... Optical card 3... Optical head 4... Objective lens 5 - Holder 6... Head carriage 8
...Position detector 10...VCM 12...
VCM control circuit 17...Switching signal generation circuit 17a...Uptown counters 1, 7 b...Arithmetic circuit 18...Differentiating circuit 2
1...Tracking control circuit 22...Sequence control circuit 21st! ! Fig. 3 Fig. 41!1 Fig. 5 Fig. 6/- Rittoi-kun - Fig. 7

Claims (1)

[Scope of Claims] An optical head provided with a light source that emits light, an objective lens that focuses the light beam from the light source onto a recording medium to form a light spot, and a track on the recording medium and the light beam. Information recording/reproduction for recording/reproducing information, comprising a drive means for relatively moving a head, and a tracking means for driving and controlling the objective lens to position a light spot on a track of the recording medium. In the apparatus, a speed detecting means for detecting a relative speed between the recording medium and the objective lens; detecting a relative positional change between the recording medium and the objective lens, and determining the center of the positional change. Also, a position variation detection means for outputting a switching signal at the center position, and a speed detection means for controlling the speed of the objective lens when the switching force signal of the position variation detection means is output during a seek operation. and a selection means for switching so that an output signal from the output signal is output to the tracking means, and after the switching means makes the switch, an on-track operation for positioning the optical spot to the target track is started. Recording and playback device.