JPH0679379B2 - Optical disc control track detector - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disc control track detecting device, and more particularly to a device capable of detecting a control track of an optical disc at high speed.

2. Description of the Related Art As a conventional optical disc control track detecting device, there is one shown in FIG.

In this figure, reference numeral 1 is a pickup arranged facing the optical disk 2, and 3 is a position sensor for detecting the position of the pickup. The pickup 1 reads data on the surface of the optical disc 1 while moving along the optical disc 2. Further, the pickup 1 emits an optical signal 4 toward the position sensor 3, and the position sensor 3 detects the position of the pickup 1 by the optical signal 4. The user area 2a is located in a certain area near the outer circumference of the optical disc 2, and the user area 2a
A control track 2b is provided closer to the center than the control track 2b. The position sensor 3 is installed so as to extend from the outer peripheral end of the user area 2a of the optical disc to the center side of the control track 2b, and a gap 5 is formed between the control track 2b and the end surface of the position sensor 3 on the center side. To be done. Then, in order to detect the control track 2b of the optical disc 1, normally, the pickup 1 is moved from the user area 2a to the center side with respect to the optical disc 2 before the data recording, and the pickup 1 controls the control track 2b. The PEP modulation signal is detected at the point where the control track 2b is reached, and the control track 2b is detected. Of course, the optical disc 2 can detect the control track 2b even after data is recorded.

However, in such a conventional optical disk control track detecting device, since the position sensor that can linearly cover the entire surface of the optical disk 2 cannot be manufactured inexpensively, the control track 2b is not manufactured. There is no choice but to narrow the interval 5 between the end surface of the position sensor 3 and the position sensor 3. As a result, the structure shown in FIG. 2 is formed, making it difficult to position the pickup 1 in a narrow space on the center side, and the pickup 1 must be moved from the outside even when detecting the control track 2b. Therefore, after the data is recorded in the user area 2a of the optical disc 2, the data similar to the control track 2b is read in the user area 2a portion, which makes the determination difficult, and the detection time for performing this determination processing is increased. There was a problem that it became long.

The present invention has been made in view of the above problems, and an object thereof is to provide an optical disc control track detection device capable of performing control track detection in a short time regardless of before and after recording of data in a user area of an optical disc. Is.

Means for Solving the Problems In order to achieve the above-mentioned object, the present invention controls to a position corresponding to the center side of a control track of an optical disc, separately from a position sensor for detecting the position of a pickup of an optical disc control track detection device. The gist of the present invention is to prevent an increase in detection time by providing a track detection sensor and searching the control track from the center side of the optical disk.

When detecting the working control track, the pickup is moved from the center of the optical disk. Since no data is recorded on the center side of the control track of the optical disc, the pickup detects the PEP modulation signal recorded on the control track without erroneously detecting a signal similar to the PEP modulation signal. Judge as detection of control track. Therefore, even after the data is recorded in the user area, the control track can be detected without increasing the time.

Embodiment FIG. 1 is a diagram schematically showing an embodiment of an optical disk control track detecting device according to the present invention.

In this figure, reference numeral 11 is a pickup arranged facing the optical disc 12, and 13 is a position sensor for detecting the position of the pickup. The pickup 11 reads the recorded data on the surface of the optical disc 11 while moving in the radial direction with respect to the optical disc 12. The pickup 11 also emits an optical signal 14 toward the position sensor 13, and the position sensor 13 receives the optical signal 14 to detect the physical position of the pickup 11. The optical disk 12 has a disk shape, and the user area is located in a certain area near the outer circumference.
12a, a control track 12b is provided inside the user area 12a, that is, on the center side. Position sensor 13
In order to cover the movement range of the pickup 11, it is installed so as to extend from the outer peripheral end of the user area 12a of the optical disk to a little closer to the center than the control track 12b.
A space 15 is formed between the control track 11b and the end surface of the position sensor 13 on the center side.

Further, in this embodiment, the second sensor 16 is provided on the center side of the control track 12b or the position sensor 13 as a sensor for detecting the control track.
Then, between the second sensor 16 and the control track 12b, the spindle motor for driving the pickup 11 and the physical size of the pickup 11 and the inside of the control track 12b of the optical disk 12 are determined from the range in which the existence of the reflective film is guaranteed. A space 17 is formed. A reflection type sensor is used as the second sensor 16 and detects that the pickup 11 is above this.

The operation of the optical disc control track detecting device having such a configuration will be described below.

When detecting the control track 12b, first the pickup 11 is set on the center side of the optical disc 12,
From there, it is moved to the outside of the optical disc 11 in the radial direction while performing the signal detection operation. Since no data is recorded on the part of the optical disk 12 closer to the center than the control track 12b, the pickup 11 proceeds without erroneously detecting a signal similar to the PEP modulated signal. Then, when the pickup 11 reaches the control track 12b, the PEP modulation signal recorded on the control track 12b is detected, and this detection is determined as the detection of the control track 12b. Therefore, even after the data is recorded in the user area, the control track can be detected without increasing the time.

As described above, according to the present invention, a control track detecting sensor is provided at a position closer to the center of the control track than the position sensor, and the control track is searched from the center of the optical disc. The advantage that the optical disc control track can always be detected in a fixed time regardless of before and after recording in the user area is obtained.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram schematically showing an embodiment of an optical disc control track detection device according to the present invention, and FIG. 2 is a diagram schematically showing an example of a conventional optical disc control track detection device. is there. 11 ... Pickup, 12 ... Optical disk, 12a ... User area, 12b ... Control track, 13 ... Position sensor, 14 ... Optical signal, 16 ... Second sensor (control track detection sensor).

Claims (1)

[Claims] 1. A pickup arranged to face an optical disk having a user area and a control track provided closer to the center of the user area, a position sensor for detecting the position of the pickup, and a control track for the optical disk. An optical disc control track detection device comprising a control track detection sensor provided at a position closer to the center side, and adapted to search the control track from the center side of the optical disc.