Dynamic information storage or retrieval – Specific detail of information handling portion of system – Radiation beam modification of or by storage medium
Reexamination Certificate
2000-11-03
2002-11-19
Huber, Paul W. (Department: 2653)
Dynamic information storage or retrieval
Specific detail of information handling portion of system
Radiation beam modification of or by storage medium
C369S121000
Reexamination Certificate
active
06483796
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a recording medium recording digital information thereon, a recording medium functioning as a nonvolatile memory, an information reproducing apparatus, an information recording apparatus, and an information recording and reproducing apparatus using the same.
BACKGROUND ART
Conventionally, as a ROM (read only memory) recording medium of digital information and an information reproducing apparatus thereof, there are a CD (compact disk) and a player of the same.
FIG. 28
is a block diagram schematically showing that apparatus.
In
FIG. 28
, reference numeral
100
is a CD and reference numeral
200
is a player.
In the CD
100
, pits
102
are formed as digital information in a signal layer
101
. A protective layer
103
and a transparent plastic substrate
104
are adhered to an upper surface and a lower surface of this signal layer
101
.
In such a CD
100
, the track pitch is set to 1.6 &mgr;m and the shortest pit length is set to 0.9 &mgr;m.
The player
200
is an apparatus which detects the existence of the pits
102
to reproduce the information of the CD
100
and is provided with an optical pick-up
201
, an RF amplifier
202
, a digital signal processing circuit
203
, etc.
Namely, a laser beam L having a wavelength of 780 nm is fired from a laser diode
210
of the optical pick-up
201
to the CD
100
side. The reflected laser beam L is detected at the photodiode
211
. The RF signal is amplified by the RF amplifier
202
, then subjected to digital processing etc. at the digital signal processing circuit
203
to reproduce the information of the CD
100
.
The CD
100
and the player
200
thereof described above, however, are structured to use a laser beam L to optically detect the pits
102
of the CD
100
, therefore there is a limit to the wavelength of that beam and the precision of detection is low. For this reason, the size of the pits
102
cannot be made small and a large amount of information cannot be recorded on the CD
100
. For example, in a CD
100
having a diameter of 12 cm, the recordable amount of digital information is about 650 megabytes.
Further, as other recording media and the information reproducing apparatuses thereof, there are the recently much talked about DVD (digital video disk) and the players thereof.
In this apparatus, the track pitch of the DVD is set to 0.84 &mgr;m and the shortest pit length is set to 0.451 &mgr;m, so the existence of the pits can be detected by a laser beam having a wavelength of 635 nm or less. Accordingly, a higher density and larger amount of information can be recorded on a DVD in comparison with the CD
100
. Nevertheless, the amount of digital information which can be recorded on a DVD of a diameter of 12 cm is about 3.9 gigabytes.
Contrary to this, when the information of the CD and DVD is detected by using a laser beam having a blue wavelength, the precision of detection is improved. However, since the pits are detected by using light, there is a limit and thus only information of a magnitude of 0.45 &mgr;m to 0.3 &mgr;m at the lowest can be detected.
Accordingly, the conventional recording media such as CDs and DVDs and the information reproducing apparatuses using the same were insufficient as multimedia apparatuses, for which recording and reproduction of a large amount of information such as moving picture information and audio information were required.
On the other hand, as a recording medium which can be recorded on and reproduced from like a nonvolatile memory of a semiconductor and an information recording and reproducing apparatus thereof, there are a so-called “Mini Disc” and a player thereof.
The “Mini Disc” recording medium is a magneto-optic disk
300
as shown in FIG.
29
and is structured with a magnetic layer
302
formed on a polycarbonate substrate
301
in a corrugated manner and with a protective layer
303
provided on the magnetic layer
302
.
When recording, the laser beam strikes the recording medium and heats the same while an external magnetic field is applied, the magnetization is inverted and information of “1” or “0” is recorded according to the orientation of the domain. Then, when reproducing, using the fact that the plane of polarization of the reflected light of the laser beam slightly rotates in a forward or reverse direction corresponding to the orientation of the magnetization of the magnetic layer (Kerr effect), the laser is irradiated, a laser beam is fired to read the orientation of the magnetization.
In the “Mini Disc” as well, however, since light is used for the sensing medium, it is not possible to exceed the limit of the wavelength of light. As shown in
FIG. 29
, the pitch of the recording width is 1.1 &mgr;m+0.5 &mgr;m, i.e., about 1.6 &mgr;m.
The present invention was made so as to solve the above problem and has as an object thereof to provide a ROM recording medium and a recording medium functioning as a nonvolatile memory enabling an increase of the capacity of the information and an improvement of the precision of the reading of the information and an information reproducing apparatus, an information recording apparatus, and an information recording and reproducing apparatus using the same.
DISCLOSURE OF THE INVENTION
According to the present invention, to achieve the above object, as a first aspect of the invention, the recording medium disclosed in claim
1
is configured provided with a substrate, a signal layer made of a metal which is fixed to the surface of the substrate, and pits formed in the same.
The recording medium disclosed in claim
1
is structured as the invention disclosed in claim
2
provided with a protective plate which covers the signal layer and is stuck to the surface of the signal layer by the state of vacuum in the pits.
The invention is configured as the recording medium with the signal layer formed by aluminum or another flexible metal conductor.
As a second aspect of the present invention, the information reproducing apparatus disclosed in claim
4
is configured provided with an electron gun which can fire an electron beam at predetermined positions of a metal medium having a signal layer made of metal in which pits are formed, a detector which can detect an intensity of the electron beam reflected from the signal layer of the recording medium, and a reproducing circuit which reproduces the information of the recording medium based on the result of detection of the detector.
Further, as a third aspect of the present invention, an information reproducing apparatus disclosed in claim
5
is configured provided with a metal body which can be arranged so as to face the signal layer at predetermined positions of a recording medium to which a predetermined voltage is applied and having a signal layer made of metal in which pits are formed, a detecting circuit which can detect the existence of a change of a potential between the metal body and the signal layer, and a reproducing circuit which reproduces the information of the recording medium based on the result of detection of the detecting circuit.
As a fourth aspect of the present invention, the recording medium disclosed in claim
6
wherein provision is made of island-like fixed electrodes electrically insulated from the periphery, electrons can be injected into the fixed electrodes by the electron gun, and injected electrons can be removed, thereby imparting a memory function to the fixed electrodes.
The recording medium disclosed in claim
7
is configured as a recording medium disclosed in claim
6
provided with a substrate, a conductive layer laminated on the substrate surface, an insulating layer laminated on the conductive layer, and island-like fixed electrodes embedded in the insulating layer.
As a fifth aspect of the present invention, the information recording apparatus of the recording medium disclosed in claim
8
is configured provided with an electron gun which injects electrons in fixed electrodes of a recording medium provided with island-like fixed electrodes electrically insulated from the periphery via t
Huber Paul W.
Kananen Ronald P.
Rader & Fishman & Grauer, PLLC
Sony Corporation
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