JPH01194146A - Optical information recording and reproducing device - Google Patents

Abstract

PURPOSE:To avoid a malfunction to detect an AT abnormality by a relative displacement by a simple means by detecting the auto focusing AT abnormality and detecting an AT error level by a tracking error in parallel. CONSTITUTION:An AT error level detecting circuit 12 is provided, whether a tracking error signal Et outputted from an AT control circuit 4 is more than a prescribed value or not is discriminated and when it exceeds the prescribed value, a signal Eh is outputted to a system controller 1. Since a second detecting means 12 to detect the AT error is provided like this, even when a relative change occurs between a recording carrier and an optical head main body by a disturbance such as an oscillation from the outside and a first detecting means 11 detects the AT abnormality, when the detection output of the second detecting means 12 is within a prescribed error range, the AT abnormality detection output by the first detecting means 11 is invalidated and the action of a system is continued.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an optical information recording and amphibious device, and more particularly to abnormality detection in tracking control for causing a light spot to follow a track on a record carrier.

[Prior Art] Conventionally, an optical head of an optical information recording/reproducing device includes a light source such as a laser, a collimator lens that converts the light beam from the light source into a parallel light beam, and a collimator lens that narrows down this light beam to form a minute light spot on the recording surface of a record carrier. It is composed of an optical system such as an objective lens that illuminates the recording surface, and a photodetector that receives the light beam reflected by the recording surface.

During recording, a beam of light modulated by predetermined information and focused by an objective lens is irradiated onto the recording surface 1- of the record carrier, and information is recorded by causing a temperature rise or chemical reaction on the recording surface. Also, during playback, a light beam reflected from the recording surface and optically modulated by the recorded information is received by a photodetector, and the detected optical signal is converted into an electrical signal to obtain the desired playback information. It is something.

Record carriers used for recording and reproducing such optical information include optical video disks, optical digital audio disks, optical cards, and the like. The information to be recorded is, for example, recorded on concentric or spiral tracks in the case of a disc-shaped carrier (hereinafter referred to as an optical disc), and in a plurality of tracks arranged in parallel in the case of a card-shaped carrier. Ru. This information track is caused by unevenness, the presence or absence of bits, changes in reflectance, changes in magnetization direction, etc.

In order to accurately record information without causing problems such as crossover between information tracks, it is necessary to control the irradiation position of the light spot in a direction perpendicular to the scanning direction of the information pattern (auto tracking, In addition, in order to irradiate the light beam as a stable minute spot despite the bending and mechanical errors of the record carrier, it is necessary to control the light beam in the direction perpendicular to the recording surface (autofocusing, (hereinafter referred to as rATJ). Also,
AT and AF are necessary even during amphibious life.

FIG. 4 is a block diagram showing the configuration of such a conventional optical information recording and recording device.

In the figure, a system controller 1 controls motors 2 and 3, a Δ'F control circuit 4, and an AF control circuit 5 to control information recording and reproduction on an optical card C.

The driver 2 reciprocates the optical card C in the direction of arrow a in the figure, thereby irradiating the light spot from the optical head 6 along the information track on the optical card C. Further, the motor 3 controls the movement of the optical head 6 in a direction perpendicular to the information track of the optical card CL.

The optical head 6 includes a light source 6a such as a semiconductor laser, and a collimator lens 6 that converts the light beam from the light source 6a into a parallel light beam.
b, a beam splitter 6C, and an objective lens 6d, and irradiates the recording surface -L of the optical card C with a light beam for recording and reproduction.

The optical head 6 also has a beam splitter 6e, condensing lenses 6f and 6g, and photoelectric converters 6h and 61, and the photoelectric converters 6h and 61 convert the light beam reflected on the recording surface of the optical card C into tracking signals and The signal is converted into a focusing signal and supplied to the AT control circuit 4 and the AF control circuit 5.

The AT control circuit 4 and the AF control circuit 5 move the objective lens 6d by passing a drive current through the tracking coil 61 and the focusing coil 6k of the optical head 6 to perform AT and AF control.

The position sensor 10 detects the relative position between the objective lens 6d and the optical head main body 6 using the tracking coil 6J, and its detection output St is supplied to the AT abnormality detection circuit 11 to determine whether or not there is a tracking abnormality.

Figure 5 shows the AT abnormality detection circuit I! 6 is a circuit diagram showing the configuration of the circuit, and FIG. 6 is a waveform diagram for explaining its operation.

In FIG. 5, the output SL of the position sensor 10
(see Fig. 6) is input to the relative speed detection circuit 11a to detect the relative speed between the objective lens 6d and the optical head 6, and is sent to the comparator llb as a voltage signal Sv (Fig. 6B) proportional to the speed. Output. comparator ll
b is a tracking abnormality detection signal Sh (Fig. 6C
) is output to the system controller 1 to report an abnormality.

Upon receiving this abnormality detection signal sh, the system controller l immediately issues a command to stop the operation.

[Problems to be Solved by the Invention] In the conventional example described above, when the relative position between the record carrier and the optical head body changes due to disturbance such as external vibration, the objective lens is moved to correct the amount of change. ,
If the amount of change is within the tracking range, the light spot can accurately follow the information track. However, in the conventional example, A i
``Since an abnormality is detected, there was a problem in that the AT abnormality was detected even though the previous spot was accurately following the information track, and the abnormality was reported to the system controller.

[Means for Solving the Problems] The optical information recording/reproducing device of the present invention scans a light spot formed by a focusing means of an optical head along a plurality of information tracks formed on a record carrier. In an optical information recording and reproducing apparatus that records and/or reproduces information, a first detection detects a tracking abnormality by detecting a relative speed between the light condensing means and the optical head in the 1rI information track arrangement direction. and second detection means for detecting a tracking error of the light spot by detecting the relative position between the information track and the light spot, the detection output of the first detection means being at a predetermined speed. Even if a tracking abnormality is detected beyond the range, when the detection output of the second detection means is within a predetermined error range, the detection output of the first detection means is invalidated. .

[Function] According to the present invention, by providing the second detection means for detecting the AT error, a relative change occurs between the record carrier and the optical head main body due to external disturbance such as vibration, and the first detection means detects the AT error.
Even if the second detection means detects an abnormality, if the detection output of this second detection means is within a predetermined error range, that is,
When the light spot has settled down to such an extent that it can follow the information track, the AT abnormality detection output by the first detection means is invalidated, and the system continues to operate.

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

FIG. 1 is a block diagram showing an embodiment of an optical information recording/reproducing apparatus according to the present invention. In addition, in this figure, the same parts as in FIG. 4 are given the same reference numerals, and detailed explanation will be omitted.

In this embodiment, a T error level detection circuit 12 is provided to determine whether the tracking error signal EL outputted from the AT control circuit 4 is greater than or equal to a predetermined value (↑11). It is configured to sometimes output the signal ah to the system controller 1, and the other configurations are the same as in FIG. 4.

FIG. 2 is a circuit diagram showing the configuration of the AT error level detection circuit 12, and FIG. 3 is a waveform diagram for explaining its operation.

In Fig. 2, the tracking error signal EL (Fig. 3 A
) is input to comparators 12a and +2b. The output of the comparator 12b is the signal El, which is the comparison voltage.
High level when greater than 1, comparator 1
The output E[- of 2c becomes high level when the signal Et is smaller than the comparison voltage 2. The OR circuit 12d is a signal Er÷
or Ef-, it is determined that the tracking error q1 exceeds a predetermined value, and AT
The system controller 1 outputs the error detection signal Eh (FIG. 3B) to the system controller l, and outputs the tracking abnormality detection signal sh from the AT abnormality detection circuit 11 and the AT error detection signal +5h from the AT error i2 level detection circuit 12. It is determined that the AT is abnormal only when both of them become high levels, and control such as immediately reducing the operation of each part to 1F is performed.

Note that in the embodiment described in 1i; 1, an information recording + 1G generation device using an optical card was described, but the record carrier is not limited to this, and the present invention can be applied to optical discs, optical desolation, etc. The effect remains the same.

[Effects of the Invention] As described above in detail, according to the present invention, when detecting a tracking abnormality and stopping the system, the AT abnormality is detected based on the relative speed between the objective lens and the optical head;
By combining this with AT error level detection based on tracking error, the record carrier and optical head may change relative to each other due to external vibrations even though tracking is operating normally, and this may cause the objective lens to change. It is possible to avoid, by a simple means, a malfunction in which Ar1"4 is detected due to relative displacement between the optical head and the optical head.

[Brief explanation of the drawing]

1 is a block diagram showing an embodiment of an optical information recording/reproducing device according to the present invention; FIG. 2 is a circuit diagram showing an embodiment of an AT error level detection circuit; FIG. 3 is a block diagram showing an embodiment of an AT error level detection circuit; 4 is a block diagram showing the configuration of a conventional optical information recording/reproducing device. FIG. 5 is a circuit diagram showing the configuration of an AT abnormality detection circuit. , FIG. 6 is a waveform diagram for explaining the operation of FIG. 5. FIG. C... Optical card... System controller 4 ・A T control circuit 5-A F control circuit 6... Optical head 6 d-... Objective lens lO - Position sensor 11... A' Abnormality detection circuit +2-...ATzH difference level detection circuit

Claims (1)

[Claims] (1) In an optical information recording and reproducing device that records and/or reproduces information by scanning a light spot formed by a focusing means of an optical head along a plurality of information tracks formed on a record carrier. , a first detection means for detecting a tracking abnormality by detecting a relative velocity between the light focusing means and the optical head in the information track arrangement direction; and a first detection means for detecting a relative position between the information track and the optical spot. and a second detection means for detecting a tracking error of the light spot, and even if the detection output of the first detection means exceeds a predetermined speed range and a tracking abnormality is detected, the second detection means detects the tracking error. An optical information recording/reproducing device characterized in that the detection output of the first detection means is invalidated when the output is within a predetermined error range.