JPH0423276A - Generating signal phase accuracy monitoring device for servo writer - Google Patents

Abstract

PURPOSE:To quickly take stage action when phase shift is generated by generating the same pattern signal successively for plural or more times of revolution setting an index signal as an origin, and detecting a timing difference. CONSTITUTION:When a command is sent from a microcomputer 15 to a pattern generation circuit 9, the circuit 9 is synchronized with a clock signal generated at a PLL 8 setting the index signal generated from a rotary encoder 5 as the origin and generates the same two servo pattern signals (a) during two times of revolution of a recording medium 3. In the first time of revolution of the servo pattern signal (a), the servo pattern signal (b) is sent to a read/write circuit 11 with the pattern circuit 10, and the timing difference between the servo pattern signal (d) immediately after write and the servo pattern signal (c) generated in the second time of revolution is inspected at a timing inspection circuit 14. By using such constitution, it is possible to quickly take the stage action when the phase shift is generated when the servo pattern is written.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a generated signal phase accuracy monitoring device in a servo writer device that writes servo patterns on a recording medium.

[Prior Art] When producing an in-air disk as a high-density recording medium, a servo pattern used for positioning a magnetic head must be written at a predetermined position with high precision and correctly. In the case of a servo pattern characterized in that all synchronization marks within a servo sector are aligned with each other, for example, in a pattern that requires phase alignment of servo pattern signals between adjacent tracks as shown in FIG. A phase shift during pattern writing becomes a fatal defect. Here, phase alignment is a technology that allows signals to be written at the same position in the circumferential direction of the recording medium any number of times, and is related to the write head, media chucking mechanism, spindle, encoder, etc. It is.

Conventional devices for inspecting the presence or absence of phase shift when writing servo patterns include: After writing the servo pattern, the recording medium is placed in a drive and the written servo pattern is used to determine the position of the magnetic head. While doing so, initialization data was written, and the quality of the servo pattern including the phase shift pattern of the recording medium was checked to see if an error occurred at this time.

Another device is to continuously reproduce the servo pattern on the recording medium, generate the same servo pattern continuously in synchronization with the rotating shaft, and check how much this servo pattern deviates from the pattern on the recording medium. The phasing performance of the servo writer device was periodically checked while observing it with an oscilloscope or the like.

Furthermore, in another device, after writing a servo pattern, the magnetic head is placed between the two (2) racks of the servo pattern, and the amplitude of the signal in the part where the phase originally matches is checked, and the phase is changed depending on the shape of the amplitude. It was used to check whether there is any phase shift and to check the degree of phase matching.

[Problems to be Solved by the Invention] A drawback of such an inspection device is that when checking initialization data when writing, only the phase alignment cannot be inspected independently, and the cause of the defect may be due to a phase alignment misalignment. Since it is not possible to identify whether or not the servo writer device is defective, it is not possible to determine whether or not there is a defect in the servo writer device, and no process action can be taken.Furthermore, since defective products are discovered during the initialization process, products with defective phase alignment may also be rejected during the process. As a result, production efficiency deteriorates.

In addition, as another device, if you want to periodically check the phase alignment performance of the servo writer device while observing with an oscilloscope or the like how much the servo pattern on the recording medium is out of alignment, it is necessary to perform regular inspections. Therefore, it is necessary to stop the production of the servo writer device each time, and checking it takes time and man-hours.

Furthermore, when checking the degree of phase matching by placing the magnetic head between two tracks of the servo pattern and inspecting the amplitude of the phase matching signal after writing the servo pattern,
Similarly, it takes time to check, and the productivity of the servo writer device deteriorates.

In order to eliminate the above-mentioned drawbacks of the conventional device for inspecting the presence or absence of a phase shift in a signal generated by a servo writer device, the purpose of the present invention is to provide a method for quickly taking process action when a phase shift occurs when writing a servo pattern. In addition, by inspecting the presence or absence of a phase shift during the production of servo writer devices, it is possible to prevent defective products with a phase shift from being passed on to the next process, increasing production efficiency, and reducing the equipment and man-hours required to check the phase shift. The goal is to make it unnecessary.

[Means for Solving Problem 11] In order to solve the above problems, the generated signal phase accuracy monitoring device of the present invention provides a servo writer device for writing a servo pattern on a recording medium. means for generating an index signal; means for generating the same servo pattern signal for two or more consecutive rotations using the index signal as a starting point; means for reading out the written servo pattern signal, and means for detecting a timing difference between the servo pattern signal generated after the second revolution and the read servo pattern signal read from the servo pattern written on the recording medium. It is characterized by having the following.

[Operation] This invention uses index number 248, which is generated in synchronization with the rotation of the recording medium, as the starting point, and continues to be the same while the recording medium rotates for two or more rotations, that is, during the writing period and the reading period of the servo pattern. A servo pattern signal is generated, the servo pattern signal generated during the first rotation is written on a recording medium, and a servo pattern No. 15 is read from the written servo pattern after the second rotation.
The phase accuracy of the generated signal is monitored by detecting the timing difference with the continuously generated servo pattern signal.

[Example] Hereinafter, an example of the present invention will be described in detail based on the accompanying drawings.

FIG. 1 shows a block diagram of a servo writer device including a generated signal phase accuracy monitoring device according to the present invention.

A servo writer device is used to encode servo patterns onto a recording medium, and this servo writer device has a precision spindle 1. A recording medium 3 is set at one end of a rotating shaft 2 of a spindle 1. A rotary encoder 5 is connected to the other end of the rotating shaft 2 of the spindle 1 through a highly rigid coupling 4 in the rotational direction.By integrating the rotary encoder 5 with the spindle 1, the rotation of the recording medium 3 is controlled. It is transmitted to the rotary encoder 5 with high precision. The rotating shaft 2 of the spindle 1 is connected to the motor 7 by a pulley 19 that also serves as a flywheel and an elastic belt 20, and vibrations caused by the rotation of the motor 7 are transferred to a rotary encoder 5.
and spindle 1.

The rotary encoder 5 sends an index signal and a rotation pulse signal synchronized with the rotation of the rotation shaft 2 of the recording medium 3 to the PLL 8, and the PLL 8 creates a clock signal based on these signals. From this PLLEI, the index signal is sent to the pattern generation circuit 9 and the pattern gate circuit 1.
0, and also sends a clock signal to the pattern generation circuit 9. The pattern generation circuit 9 constitutes a means for generating the same servo pattern signal continuously for two or more rotations using the index No. 243 as a starting point using a clock signal. This servo pattern signal (a) is sent to the pattern gate circuit 10,
When writing to the recording medium 3, the servo pattern signal (b) is sent to the read/write circuit 11 for writing and reading. This read/write circuit 11 is electrically connected to a head carriage 13 having a magnetic head 12, which constitutes a writing means for writing a servo pattern onto the recording medium 3, and also constitutes a reading means for reading the written servo pattern. The means are constituted.

A timing test circuit 14 is connected to the read/write circuit 1, and a pattern gate circuit 10 is connected to the timing test circuit 14. This pattern gate circuit 10 detects the servo pattern signal ( C) is sent to the timing inspection circuit 14, and this timing inspection circuit 14 sends the servo pattern signal (C) to the timing inspection circuit 14.
) and the read servo pattern signal (d) read from the servo pattern written on the recording medium 3 (d).

The timing check circuit 14 includes a microcomputer 15.
is connected to the microcomputer 15, and information for determining the phase shift of the generated signal of the servo pattern is sent to the microcomputer 15.

The microcomputer 15 outputs command signals to the mechanical controller 16 and the stage controller 17 based on information for determining phase shift and operation signals from external switches and the like. The stage controller 17 controls the stage 18 so that the magnetic head 12 is positioned on an arbitrary track.
control.

The mechanical controller 16 drives the motor 7 and controls a recording medium supply/discharge mechanism (not shown) on the basis of command signals.

Next, the operation of the generated signal phase accuracy monitoring device of the servo writer device will be explained.

As shown in FIG. 2, the servo writer device uses the index signal as a starting point during the servo pattern writing period T1. A servo pattern reading inspection period T2 and a head movement period T3 are set sequentially.

A command is sent from the microcomputer 15 to the pattern generation circuit 9. This pattern generation circuit 9 is synchronized with a clock signal using the index signal generated from the rotary encoder 5 as a starting point, and is operated during a period other than the head movement period T3 in which the magnetic head 12 moves, while the recording medium 3 rotates twice, that is, the servo pattern is generated. A servo pattern signal (a) is generated during write period child 1 and servo pattern read test period T2. Here, the two servo pattern signals (a) generated by the pattern generation circuit 9 are completely the same. This servo pattern signal (a) is sent to the read/write circuit 11 for the first rotation using the pattern gate circuit 10, and the same servo pattern signal (C) is sent to the timing inspection circuit for the second rotation. Send to 14th.

On the other hand, when the read/write circuit 11 finishes writing the servo pattern for one rotation, the magnetic head 12 reads out the servo pattern just written for the next rotation, and this servo pattern signal (d) is sent to the timing check circuit 14.

Therefore, the servo pattern signal (C) sent from the pattern gate circuit 10 and the read servo pattern signal (d) are input to the timing inspection circuit 14 at the same time.

The timing of both servo pattern signals (C) and (d) is '! This will be explained using Figure J3 and Figure 4.

The servo pattern signal (a) in FIG. 3 is a signal generated by the pattern generation circuit 9, and the servo pattern signal (b) is a servo pattern signal (C) indicating a signal sent by the pattern gate circuit 10 during writing. is exactly the same as the servo pattern signal (b), but is a signal sent to the timing inspection circuit 14 during inspection. The servo pattern signal (d) is a signal read by the magnetic head 12 and sent to the timing inspection circuit +4 via the read/write circuit 11.

FIG. 4 is an enlarged view of the part surrounded by the dotted line in FIG. 3, showing the timing of the servo pattern signal (C) and the servo pattern signal (d). The difference X between the servo pattern signal (C) and the servo pattern signal (d) indicates a phase shift, and this is inspected by the timing inspection circuit 14.

Next, this timing inspection circuit will be explained.

It is also possible that the phase shift exceeds the minimum pulse interval of the servo pattern signal. In this case, measuring the phase shift for every pulse requires a complicated circuit. Also, considering that the phase shift does not change rapidly with small rotation angles of spindle 1, an effective method is to treat a group of pulse trains with narrow pulse intervals as one block and inspect each block separately. becomes.

For example, in the servo pattern in Figure 4, the first three
The test was divided into three blocks: a pulse, one pulse in the middle, and the last four pulses.

The circuit configuration of this timing inspection circuit will be explained using FIG. 5.

The servo pattern signals (C) and (d) are applied to each retriggerable monostable multivibrator 30.31
The exclusive OR circuit 32
is input to. In this exclusive OR circuit 32, the phase shift between the first and last pulses of each block is indicated by the exclusive OR of the two blocked signals, and is inputted to an AND circuit 33. The pulse width indicating the amount of phase shift is detected using the clock 34 and the counter 35, the digital comparator 36 discriminates whether the pulse width is small or small, and the result is temporarily stored in the flip-flop 37 for inspection by the microcomputer 15. You can send information.

By performing the phase shift test in this manner, the phase performance of the servo writer device can be monitored.

[Effects of the Invention] As described above, the present invention detects the timing difference between the servo pattern signal generated after the second rotation of the recording medium and the read servo pattern signal read from the servo pattern written on the recording medium. The servo pattern readout inspection period is used to inspect the readout servo pattern signal when inspecting the already written servo pattern signal, rather than directly comparing the phases of two actually written adjacent tracks. Phase performance is monitored by comparing the pattern signal with the servo pattern signal generated by the pattern generation circuit, allowing for efficient real-time monitoring.

Therefore, if a phase shift occurs when writing a servo pattern, process action can be taken quickly, and by monitoring the presence or absence of a phase shift during the production of the servo writer device, defective products with a phase shift can be passed on to the next process. Therefore, production efficiency can be improved, and the need for phase shift checking equipment and man-hours can be eliminated.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a servo writer device including a generated signal phase accuracy monitoring device according to the present invention, and FIG. 2 is an explanatory diagram showing the timing of writing, reading, and head B movement of a servo pattern starting from an index signal. , Fig. 3 is an explanatory diagram showing the timing of the pattern signal, Fig. 4 is an enlarged explanatory diagram showing the timing of the pattern signal, Fig. 5 is a specific circuit configuration diagram of the timing inspection circuit, and Fig. 6 is an explanatory diagram showing the timing of the pattern signal. FIG. 2 is an explanatory diagram of a servo pattern characterized in that synchronization marks are aligned with each other. In the figure, 1 is a spindle, 2 is a rotating shaft, 3 is a recording medium,
5 is a rotary encoder, 7 is a motor, 9 is a pattern generation circuit, 10 is a pattern gate circuit, 11 is a read/write circuit, 12 is a magnetic head, ! 4 is a timing inspection circuit, 15 is a microcomputer, 16 is a mechanical controller, and 17 is a stage controller. Patent Applicant: Konica Co., Ltd.

Claims (1)

[Claims] In a servo writer device for writing a servo pattern on a recording medium, means for generating an index signal synchronized with the rotation of the recording medium, and means for generating the same servo pattern signal for two or more consecutive rotations starting from this index signal. a means for writing a servo pattern signal generated in the first rotation onto a recording medium and reading out the written servo pattern signal in the second and subsequent rotations, a servo pattern signal generated in the second and subsequent rotations, and a recording medium. A generated signal phase accuracy monitoring device in a servo writer device, comprising means for detecting a timing difference between a read servo pattern signal read from a servo pattern written in the servo pattern.