JPH01196734A - Drive device for optical disk - Google Patents

Abstract

PURPOSE:To prevent operator's erroneous judgement in case of the occurrence of surface inclination due to a factor other than the defect of an optical disk itself by detecting and displaying that a tracking error signal continuously exceeds a prescribed value. CONSTITUTION:The laser light from a light source 1 is reflected on a surface 8 of an optical disk 7 and is focused on the center part of a four-divided photo diode 11 through a beam splitter 4, a knife edge 10 which intercepts the upper half of the light, etc. Though output RF and TE signals of the diode 11 indicate fixed values when the laser light as the checking light is in the in-focus state to perform tracking, thee signals exceed specific threshold values when the laser light traverses a groove or is inclined, and this state is detected by values of these signals. The surface inclination of the optical disk to a drive table is displayed when these values continuously exceed prescribed values, thus preventing the operator from erroneously judging the optical disk itself to be defective.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an optical disc drive device n that supports, for example, an optical disc on a drive table, rotates it, and optically reads information recorded on the optical disc.

(Conventional technology) This type of conventional optical disc drive device.

If the surface inclination when setting an optical disk on the drive table exceeds a predetermined value, tracking failure may occur or the rotational drive may stop. Incidentally, it has been empirically recognized that such a surface inclination of the optical disk with respect to the drive table that exceeds a predetermined value is often caused by foreign matter such as dust adhering to the magnetic plate for chucking the disk.

However, in conventional optical disk drive devices, there is no means for directly detecting the surface inclination of the optical disk with respect to the drive table, so even if the surface inclination is caused by foreign matter, tracking failure or drive stoppage may occur. If this occurs, there is a risk that the operator may mistakenly judge that the optical disk itself is defective.

(Object of the Invention) The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide an optical disc drive device that can detect that the surface inclination exceeds a predetermined value.

(Structure of the Invention) In order to achieve the above object, an optical disc drive device according to the present invention is an optical disc drive device that supports an optical disc on a drive table, rotates it, and optically reads information recorded on the optical disc. a tracking error detection means for detecting a tracking error signal of the optical disc; a determination means for determining whether the detection signal by the tracking error detection means has continuously exceeded a predetermined value; and a display means for displaying that the surface of the drive table is inclined with respect to the drive table.

Hereinafter, the present invention will be explained in detail based on preferred embodiments.

FIG. 1 shows an optical disc drive unit (H) according to an embodiment of the present invention.

First, to explain the configuration, the cliff conductor laser element 1 is a light source that outputs laser light, and the laser light output from the semiconductor laser element 1 is converted from a divergent light to an Iε destination by a coupling lens 2. , the wavelength is converted by a wavelength conversion plate. This laser light passes through the beam splitter 4 and the λ/4 handler 5 and enters the objective lens 6.

The objective lens 6 is connected to an actuator (not shown), and the actuator moves in the focusing direction (optical axis direction) and the tracking direction (parallel to the disk surface), respectively, according to the focusing servo control signal and the tracking servo control signal. Move the objective lens 6.

Next, the laser beam guided by the objective lens 6 is
It is reflected by the standby surface 8 of the optical disk 7 and enters the objective lens 6 by 1[l]. The reflected light incident on the objective lens 6 is converted into a traveling light, passes through the λ/4 plate 5, and is further reflected by the beam splitter 4.

When one reflected light passes through the convex lens 9, since the upper half of the optical axis is blocked by the knife IO, only the lower half is focused and focused on the center of the odd diode 11 (divided into four parts).

Each portion of the four-division photodiode 11 is connected to a preamplifier 12 as shown in FIG. 2, for example. The preamplifier 12 converts the optical signal received by each part of the 4-split photodiode 11 into an electrical signal, and outputs the RF multiplied signal as a TE multiplied signal which is a tracking error signal.

That is, when the laser beam serving as the inspection light is focused and tracking, the reflected light is focused on the center of the 4-split photodiode 11, so the RF multiplied signal indicating the tracking state is a constant signal. Output. On the other hand, when the laser beam crosses the groove, the T
An E-fold signal is obtained. These signals are determined by the groove and bit geometry. The above four-division photodiode 11
The preamplifier 12 constitutes tracking error detection means.

The preamplifier 12 inputs the signal to a comparator l:3 which serves as a TE multiplied signal determination means. A threshold value setter 4 is connected to the input side of the comparator 13, and a CRT is connected to the output side as a display means.
+5 is connected. The threshold value setter 14 sets the threshold value Δ1 of the 1'E signal to be detected as shown in FIG. 4, for example.
A2 can be set. The threshold (lI'iAl is set, for example, from the 0 level to the + side, and the threshold value 2 is set, for example, from the O level to one side. The threshold values A1 and A2 determine whether or not the information on the optical disc 7 can be read, for example. Although the threshold value is set as a threshold value for determination, it goes without saying that it may be set to another value.In this case, the cause of the surface inclination of the optical disc can be estimated to some extent.

Philippine IP! 2 unit 13 compares the TE multiplied signal from the preamplifier 12 with the threshold value set in the threshold value setter 14 with 1 and A2. The comparator 13 determines that the absolute value of the TIE signal continuously exceeds the threshold 4Q or is continuously smaller than the threshold A2, that is, TI? , when it is determined that the absolute value of the signal has continuously exceeded the threshold value Δ2, a signal is output to CRT+5, and the signal is output to CRT+5.
5 displays to inform the operator that the optical disc 7 is tilted relative to the drive table.

Next, the effect will be explained.

In the above configuration, if the TE signal input from the preamplifier 21 to the comparator 13 is, for example, the a signal shown in FIG. Displays that the surface is tilted to the + side with respect to the drive table. Furthermore, when the TE signal is the b signal in the figure, the b signal is continuously smaller than the threshold value A2, so the CRT + 5 indicates that the optical disk is tilted to one side with respect to the drive table. .

If the optical disk 7 has a large surface inclination, 'I'
E signal indicates offset. This is often due to foreign matter such as dust adhering to the disk chucking magnetic plate. Therefore, in this embodiment, for example, CR'"+5" can be configured to display that a foreign object is attached to the optical disk.

As mentioned above, in this embodiment, the absolute value of the TE signal is the threshold value Δ
If it exceeds l and Δ2, the CRT 15 can display a message indicating that foreign matter is attached to the optical disc. For this reason,
The operator can detect that the surface inclination of the optical disk 7 is due to adhesion of foreign matter5, and even if tracking failure or drive stoppage occurs, the operator will not mistakenly judge that the optical disk itself is defective.

Note that the present invention is not limited to the above-mentioned embodiments; for example, if the video signal is not continuous but is a periodic or irregular signal, it may be caused by the optical disc itself or is a problem with another drive system, etc., so the CRT +
5 may be configured to display that fact.

Furthermore, it is of course possible to use a buzzer or the like that generates a warning sound instead of the CRTl 5 as the display means.

(Effects of the Invention) As explained above, according to the present invention, the configuration is such that it is possible to detect and display that the tracking error signal continuously exceeds a predetermined value, so that the operator can identify the cause of the surface inclination. Even though the optical disk itself is not defective, the error I'
11 can be prevented from being disconnected.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram of an optical disk drive device according to an embodiment of the present invention, FIG. 2 is a circuit diagram of FIG. 1, FIG. 3 is a diagram showing a general tracking error signal, and FIG. 4 is a diagram showing a general tracking error signal. FIG. 3 is a diagram showing a tracking error signal according to a main part of the present invention. 7... Optical disk 11... 4-split photodiode 12... Preamplifier 13... Comparator (determination means) +5... CRT (display means) Special r [Applicant: Ricoh Co., Ltd.

Claims (1)

[Claims] An optical disc drive device that supports and rotates an optical disc on a drive table and optically reads information recorded on the optical disc, comprising a tracking error detection means for detecting a tracking error signal of the optical disc, and the tracking error detection means. and a display means for displaying that the optical disc is tilted relative to the drive table based on the determination by the determination means. An optical disc drive device featuring: