JPH08249733A - Information processing device - Google Patents

Abstract

(57) [Summary] [Object of the Invention] It is an object of the present invention to provide an information processing apparatus provided with means capable of accurately outputting a synchronization signal during recording and reproduction. In order to achieve the above object, the present invention provides an information processing apparatus for detecting and recording a signal generated by a physical phenomenon between a probe and a recording medium facing the probe, and detecting the signal from the probe during recording and reproduction. Recording bit based on signal
An information processing apparatus, comprising: means for generating a center position signal indicating the center position of the center position and a reference signal synchronized with the center position signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information processing apparatus for recording / reproducing by detecting a signal generated by a physical phenomenon between a probe and a recording medium facing the probe, and more particularly, a synchronizing signal output means at the time of recording / reproducing. The present invention relates to an information processing device including.

[0002]

2. Description of the Related Art In recent years, a scanning tunneling microscope (hereinafter abbreviated as STM) has been developed which can directly observe the electronic structure of surface atoms of a conductor [G. Binnig et al. Ph
ys. Rev. Lett, 49, 57 (1982)],
It has become possible to measure real space images with high resolution regardless of whether they are single crystals or amorphous. The STM utilizes the fact that a tunnel current flows when a voltage is applied between a metal probe (probe electrode) and a conductive substance to bring them closer to a distance of about 1 nm. This current is very sensitive to changes in the distance between the two. By scanning the probe so that the tunnel current is kept constant, it is possible to read various kinds of information regarding the whole electron cloud in the real space. At this time, the resolution in the in-plane direction is 0. It is about 1 nm. Therefore, if the principle of STM is applied, it is possible to sufficiently perform high-density recording / reproducing on the atomic order (sub-nanometer). For example, JP-A-61-1
In the recording / reproducing apparatus disclosed in Japanese Patent No. 80536,
Atomic particles adsorbed on the surface of the medium are removed by an electron beam or the like and writing is performed, and this data is reproduced by STM. Further, as the recording layer, a material having a memory effect on the switching characteristics of voltage and current, for example, a thin film layer of a conjugated π-electron organic compound or chalcogen compound is used,
A method of performing recording / reproduction by STM has been proposed [JP-A-63-161552 and JP-A-63-1615].
No. 53]. According to this method, a recording bit size of 10 nm and a large capacity recording / reproduction of 10 ¹² bit / cm ² are possible. Furthermore, for the purpose of miniaturization, there has been proposed an apparatus for forming a plurality of probes on a semiconductor substrate and displacing a recording medium facing the probes for recording.
No. 196751). For example, by combining the multi-probe head in which 2500 probes are arranged in a matrix of 50 × 50 on a silicon chip of 1 cm ² square and the material having the memory effect described above, 400 Mbit per probe and a total recording capacity of 1 Tbit of digital data are obtained. Recording and playback of can be performed.

In such an information processing apparatus, a method of actually combining a probe and a medium facing the probe and extracting a synchronizing signal from a detection signal from the probe during reproduction processing has not been sufficiently developed so far. Instead of using an optical disk or a magnetic disk, a method of using a change position of a recording bit such as an edge of a reflectance change or a position of magnetization reversal is used for a rising edge of a sync signal.

[0004]

However, the above-mentioned b
There are the following problems when the change position of it is used for extracting the synchronization signal. That is, there is a problem that the detection signal cannot be synchronized during recording and reproduction due to the phase shift of the reproduction signal during probe scanning, and stable control cannot be performed. This will be described with reference to FIG. 2. When the probe scans the bit row in FIG. 2, the phase of the reproduction signal changes depending on the scanning path. For example, when the line of FIG. 2a is scanned, the reproduction signal of FIG. 2b is obtained. Therefore, the binarized signal of those signals is shown in FIG. 2c. It can be seen that this is out of phase as shown in FIG. 2e as compared with FIG. 2d which is an ideal signal obtained when the center of the bit row is scanned. And this shift amount is the third bit whose scanning position is far from the center of the bit.
It is getting bigger. When such a phase-shifted signal is used for synchronization and used as a reproduction signal, it causes data jitter in the time direction, which lowers the S / N ratio and deteriorates the performance of the apparatus.

Therefore, it is an object of the present invention to solve the above problems and to provide an information processing apparatus equipped with means capable of accurately outputting a synchronizing signal during recording and reproduction.

[0006]

In order to achieve the above object, the present invention generates a sync signal using a center position signal indicating the center position of a recording bit, and outputs the sync signal at the time of recording / reproducing with high accuracy. It is something that is done. That is, in an information processing apparatus that performs recording / reproduction by detecting a signal generated by a physical phenomenon between a probe and a recording medium facing the probe, the center position of the recording bit is indicated based on a detection signal from the probe during recording / reproduction. Generate a center position signal,
It is characterized by comprising means for generating a reference signal synchronized with the center position signal.

[0007]

According to the present invention, the synchronization signal is generated by using the center position signal indicating the center position of the recording bit as described above, so that the probe can be well synchronized regardless of the position on the bit row, and the recording can be performed. The synchronizing signal at the time of reproduction can be accurately output, and a highly reliable information processing apparatus with an improved S / N ratio can be realized.

[0008]

EXAMPLES Next, the present invention will be described in detail based on examples. FIG. 1 shows an information processing apparatus that is an embodiment of the present invention. The information processing apparatus shown in this embodiment uses a recording medium facing a plurality of probes for detecting a tunnel current. The probe shown in FIG. 1 has USP49128
In the cantilever type piezo bimorph cantilever 102 disclosed in No. 22, a tip 103 of 5 μm in height is attached to the tip of the cantilever by an electron beam deposition method using carbon or the like.
Was used. This is an actuator that can be driven in three directions and is manufactured on the Si substrate 101 by using anisotropic etching or the like. The whole multi-probe head is X
The Y scanning mechanism 105 scans in the XY directions. The scanning signal is a triangular wave generated by the scanning circuit 106. When the Tip on the probe scans the medium during reproduction, the detection signal FIG. 3a is obtained according to the information written from the current-voltage conversion circuit 104. The binarized signal (FIG. 3b) of the signal is generated by the binarization circuit 107, and the differential signal of FIG. 3c is generated by the differentiation circuit 108. 0 cross detection signal of differential signal (Fig. 3d)
Are generated by the zero cross detection circuit 109. In the 0-cross signal of FIG. 3d, a 0-cross point appears at a position other than the bit center position due to the noise component included in the differential signal of FIG. 3c. The AND circuit 110 obtains the AND signal (FIG. 3e) of both the 0-cross detection signal of FIG. 3d and the binarized signal of the detection signal (FIG. 3b). The AND signal of FIG. 3e becomes a bit center position signal indicating the bit center position. 1 using the AND signal of FIG. 3e
A reference signal (FIG. 3f) synchronized with the bit center position is generated by the 11 phase-locked oscillator. The presence or absence of the bit center position signal of FIG. 3e is determined as a reproduction signal by using the reference signal of FIG. 3f as a discrimination window. As a result, the data for each probe is stored in the buffer memory 112 with good time accuracy. The reproduced signals from each probe are collected by the parallel-serial conversion circuit 113, converted into serial signals, and output as reproduced signals. Although only one input signal is input to the parallel-serial conversion circuit 123, the reproduction signal from each probe is actually input. For actual recording on a recording medium, squarylium-bis-6-octylazulene having an electric memory effect by epitaxial growth of Au on a smooth substrate obtained by cleaving mica as a recording medium 114 and having an electric memory effect thereon is formed. It is a recording medium in which two layers (hereinafter abbreviated as SOAZ) are accumulated. That is, the recording medium 114 includes the substrate 115 and the base electrode 11.
6 and the recording layer 117. The distance between the recording medium and each probe is maintained at a position where the atomic force acting between the recording medium and the tip of the probe is balanced with the repulsive force determined by the elastic constant of the cantilever. And 100m during playback
A bias voltage of about v is applied between the two by the bias voltage generating circuit 118, and a current of about 2 nA flows. At the time of recording, the recording / erasing signal controller 120 controls the recording pulse to be output from the pulse generator 119.

[0009]

As described above, according to the present invention, the synchronizing signal is generated by using the center position signal indicating the center position of the recording bit.
Good synchronization can be obtained regardless of the position on the t-th row, and the synchronization signal at the time of recording / reproducing can be accurately output.
It is possible to realize a highly reliable information processing device having an improved / N ratio.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an apparatus according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a conventional synchronization signal detection method.

FIG. 3 shows each processed signal in the process of detecting a synchronization signal in the embodiment.

[Explanation of symbols]

 10 l Si substrate 102 Piezo bimorph cantilever 103 Tip 104 Current-voltage conversion circuit 105 XY scanning mechanism 106 XY scanning circuit 107 Binarization circuit 108 Differentiation circuit 109 0 Cross detection circuit 110 AND circuit 111 Phase locked oscillator 112 Buffer memory circuit 113 Parallel serial conversion Circuit 114 Recording Medium 115 Mica Substrate 116 Base Electrode 117 Recording Layer 118 Bias Voltage Applying Circuit 119 Pulse Generating Circuit 120 Recording Erase Signal Control Section

Claims (1)

[Claims] 1. An information processing apparatus for recording / reproducing by detecting a signal generated by a physical phenomenon between a probe and a recording medium facing the probe, the center of a recording bit based on a detection signal from the probe at the time of recording / reproducing. An information processing apparatus comprising: a center position signal indicating a position; and a reference signal synchronized with the center position signal.