JPH01107341A - Recording and reproducing device for electric wire - Google Patents

Abstract

PURPOSE:To improve an access speed by detecting deviation between the position of an electronic beam source and the center of a track from the jogging of the electronic beam source due to a fine adjusting mechanism and a distance change between the electronic beam source and a recording medium, and returning the electronic beam source onto the center of the track. CONSTITUTION:A signal which is obtained by adding DC component to the output of an oscillator 11 drives a piezo-electric element 7 by using a control circuit 12, a cathode tip 5 is vibrated in a V-groove in the radial direction of the disk 1, a detection circuit 13 fetches the change of a driving voltage in piezo-electric element 6, required for making an electric field radiation current at that time constant. The size of dislocation can be known from the output voltage of the oscillator 11, and the direction of dislocation can be known from correspondence between the differential waveform and the driving waveform of the piezo-electric element 6. A detection circuit 13 detects the deviation between the position of the center of the groove and the center of the vibration of the cathode tip 5 and it is inputted to a control circuit 12 as a tracking single. Thus, the electronic beam source can accurately be positioned at high speed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an information recording/reproducing apparatus using an electron beam, and particularly to an electron beam recording/reproducing apparatus suitable for high-density recording.

[Conventional technology]

As one type of electron beam recording/reproducing apparatus, a recording/reproducing method using a rotating disk as a recording medium has been attracting attention in recent years because the recording medium can be exchanged and, in principle, large-capacity recording is possible. This method is similar to magnetic disks and optical disks.

However, when using an electron beam, the positioning method during recording and reproduction, that is, the tracking method, becomes more important in order to effectively utilize its high convergence. As a tracking method, a method using scattered electrons from the recording track has been proposed in Japanese Patent Laid-Open No. 60-29953.

In this method, at least two detection means such as secondary electron beams are installed with a track in between near the position where the electron beam is irradiated onto the recording disk, and the outputs of these means are compared.
This is a tracking method.

[Problem that the invention seeks to solve]

The above conventional technology does not consider the need to install a dedicated detector to detect secondary electrons, etc., and instead moves a movable electron beam source in the radial direction of the disk. When used in a recording/reproducing system, there is a problem in that the recording/reproducing head, which is a movable part, becomes heavy and the access speed becomes slow.

SUMMARY OF THE INVENTION An object of the present invention is to provide an electron beam recording and reproducing apparatus that can perform accurate tracking and that does not slow down access speed.

[Means for solving problems]

The above object is to provide an electron beam recording and reproducing apparatus having a recording medium having convex or groove-shaped tracks for recording an electron beam, and an electron beam source for irradiating the recording medium with an electron beam.
a fine movement mechanism for finely moving the electron beam source in a direction perpendicular to the track substantially within a recording surface; and a detection means for detecting a distance between the electron beam source and the recording medium; The shift between the position of the electron beam source and the center of the track is detected from the slight movement of the electron beam source and the distance change between the electron beam source and the recording medium caused by the slight movement, and the electron beam source is moved to the center of the track. This is achieved by an electron beam recording/reproducing device characterized in that it has means for pulling back onto the center.

The fine movement mechanism described above may be of any type. For example, a method may be used in which a piezoelectric element is attached next to the electron beam source and the electron beam source is slightly moved by changing the driving voltage of the piezoelectric element. The direction of the microtremor is determined by the fact that the recording medium is a disk and
When the track has a concentric or spiral shape,
Its radial direction. It is preferable that the fine movement be less than or equal to the width of the track because the deviation between the position of the electron gun and the position on the center of the groove can be easily determined. The track may be a groove or a convex portion, but if the shape of the track changes due to recording, for example, if a hole is formed in the track, it is preferable that the track be a groove. There are various recording methods in electron beam recording, and in addition to changing the shape of the recording member, there are also cases where the material is partially changed. In such cases, the track may be a groove or a convex part. There may be.

The distance between the electron beam source and the recording medium may be measured by any method. For example, a weak field emission current is passed from an electron gun, and the distance can be determined from this current.

[Effect]

In a recording/reproducing apparatus using an electron beam, an electron beam source can be positioned at a desired position on a recording medium quickly and accurately without using a dedicated detector. This results in
Reliable recording and playback is possible even with minute recording pits.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG.

In FIG. 1, a disk 1 has a diameter of 6 inches and has a V-shaped track groove 2 having a width of 0.3 mm and a depth of 0.1 mm. A recording film consisting of a nitrocellulose film 3 with a thickness of 0.1 nm and an Au film 4 with a thickness of 20 nm is formed on this disk. The cathode tip 5 facing this disk is made by electric field polishing a W wire of 0.1 mm, and is made by piezoelectric element 6 in the direction perpendicular to the disk surface and piezoelectric element 7 in the radial direction of the disk. It is possible to move within a maximum range of 5p. The piezoelectric element 7 is used for fine movement for tracking operation, and a separate mechanism for driving the entire recording/reproducing head is provided as a coarse movement mechanism for track selection.

When the distance between the cathode tip and the disk is brought closer to about 0.5 groove, a high electric field is generated at the tip of the cathode tip even if the applied voltage is low, and a field emission current corresponding to the distance can be obtained. The field emission current flows through the resistor 8 and creates a potential difference across the resistor. After this potential difference is detected and amplified by the amplifier 9, the servo circuit 10 compares it with a set voltage. According to this result, the piezoelectric element 6 is driven to adjust the distance between the cathode tip and the disk so that the field emission current is constant.

Furthermore, the control circuit 12 is used to drive the piezoelectric element 7 using a signal obtained by adding a DC component to the output of the oscillator 11, and the cathode tip is moved in the V-groove to a width of 0.1/7II in the radial direction of the disk.
vibrated at a period longer than the period of the recording pit. Since the change in the drive voltage of the piezoelectric element 6 necessary to keep the field emission current constant at this time is synchronized with the output of the oscillator 11, this change is extracted by the detection circuit 13. When the cathode tip is located above the center of the groove, the driving voltage of the piezoelectric element 6 becomes maximum.

Further, the magnitude of the deviation can be determined from the output voltage of the oscillator 11, and the direction of the deviation can be determined from the correspondence between this differential waveform and the driving waveform of the piezoelectric element 6. From these, the deviation between the position of the groove center and the center of vibration of the cathode tip is detected by the detection circuit 13 and inputted as a tracking signal to the control circuit. This ensures that the deviation between the cathode tip and V# is always ±50.
It was possible to make it within nm.

FIG. 2 shows changes in the drive voltages of the piezoelectric elements 6 and 7 during these operations. Figures 2 (a) and (b) show that the cathode tip is on the center of the track groove (tracking is applied), while Figures 2 (c) and (d) show that both are misaligned (tracking is off). This is the case. In order to perform this tracking operation, a voltage is always applied to the cathode and a field emission current of 1 nA is caused to flow regardless of recording or reproduction, but this current did not damage the recording film.

During readout, if there are recording pits where the nitrocellulose film has disappeared, the distance between the cathode tip and the disk increases by the thickness of the film, and the field emission current decreases. Since this current change has a higher frequency component than the distance change between the cathode tip and the disk or the change in the tracking signal, it can be separated using a bypass filter, and the presence or absence of pits can be detected as a change in the field emission current. I was able to do that. For writing, a pulse voltage with a width of 1 μsec is further superimposed and applied as the cathode applied voltage, and a pulse voltage of about 100 nm is applied.
When a current of A was applied, the nitrocellulose disappeared and pits with a diameter of 0.2 cape were formed on the recording medium.

〔Effect of the invention〕

According to the present invention, it has become possible to accurately record and reproduce pits with a diameter of 0.2 - at a desired position on a recording medium without sacrificing access speed.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of an electron beam recording/reproducing apparatus according to an embodiment of the present invention, and FIG. 2 is a diagram showing changes in piezoelectric element driving voltage related to tracking operation. 1...Disc 2...Track groove 3...
・Nitrocellulose membrane 4...Au membrane 5...Cathode tip 6
... Distance adjustment piezoelectric element 7 ... Tracking piezoelectric element 8 ... Resistor 9 ... Amplifier 10 ...
Servo circuit 11... Oscillator 12... Tracking control circuit 13... Detection circuit Patent attorney Junnosuke Nakamura (See Figure 2) (C) Gin! ! ! 1 hour open (b)
(d)

Claims (1)

[Scope of Claims] 1. An electron beam recording and reproducing apparatus having a recording medium having convex or groove-shaped tracks for recording an electron beam, and an electron beam source for irradiating the recording medium with an electron beam, a fine movement mechanism for finely moving the electron beam source in a direction perpendicular to the track substantially within a recording surface; and a detection means for detecting a distance between the electron beam source and the recording medium; The shift between the position of the electron beam source and the center of the track is detected from the slight movement of the electron beam source and the distance change between the electron beam source and the recording medium caused by the slight movement, and the electron beam source is moved to the center of the track. An electron beam recording/reproducing device characterized by having means for pulling back onto the center. 2. The electron beam recording and reproducing apparatus according to claim 1, wherein the recording medium is a disk, and the tracks are formed concentrically or spirally. 3. The electron beam recording and reproducing apparatus according to claim 1, wherein the fine movement mechanism is a piezoelectric element attached to the side of the electron beam source. 4. The electron beam recording and reproducing apparatus according to claim 1, wherein the detecting means is means for detecting a change in distance using an emission current for a read current.