Patent EP0164577A1 successfully refreshed from Google Patents.
EP0164577A1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Optical information recording/reproducing system
Assignee: Toshiba Corp
•
Filing: 1985-05-09
•
Granted: —
•
Expires: 2005-05-09
Abstract
Abstract Disclosed is an optical information recording/reproducing system comprising: a recording medium composed of a recording- bit producing layer, which is formed of a fluorescent substance (2), and a photoconductive layer (3), both interposed between conductive layers (4, 1) at least one of which is transparent; means for selectively applying a voltage to both sides of the recording medium; means for radiating an optical recording beam to a site to be recorded on the recording medium while applying a voltage to the recording medium and then, applying a high electric field to the recording-bit producing layer by way of the photoconductive layer the resistence of which has been lowered at the site, whereby developing a dielectric breakdown and hence causing the fluorescent substance to lose the fluorescence thereof so that information is recorded; and means for radiating an optical reproducing beam on the recording medium without applying any voltage to the recording medium and then, reproducing information depending on whether fluorescence has been produced.
Inventors
- 👤 Katsutarou Ichihara
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 01:08
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/12; G11B7/135; G11B7/1362; G11B13/00; G11B7/004; G11B7/24
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
156 words
An optical information recording/reproducing system comprising: a recording medium composed of a recording-bit producing layer, which is formed of a fluorescent substance, and a photoconductive layer, both interposed between conductive layers at least one of which is transparent; means for selectively applying a voltage to both sides of the recording medium; means for radiating an optical recording beam to a site to be recorded on the recording medium while applying a voltage to the recording medium and then, applying a high electric field to the recording-bit producing layer by way of the photoconductive layer the resistance of which has been lowered at the site, whereby developing a dielectric breakdown and hence causing the fluorescent substance to lose the fluorescence thereof so that information is recorded; and means for radiating an optical reproducing beam on the recording medium without applying any voltage to the recording medium and then, reproducing information depending on whether fluorescence has been produced.
Claim 2
Dependent Claim
156 words
An optical information recording/reproducing system comprising: a recording medium composed of a recording-bit producing layer, which is formed of a fluorescent substance, and a photoconductive layer, both interposed between conductive layers at least one of which is transparent; means for selectively applying a voltage to both sides of the recording medium; means for radiating an optical recording beam to a site to be recorded on the recording medium while applying a voltage to the recording medium and then, applying a high electric field to the recording-bit producing layer by way of the photoconductive layer the resistance of which has been lowered at the site, whereby developing a dielectric breakdown and hence causing the fluorescent substance to lose the fluorescence thereof so that information is recorded; and means for radiating an optical reproducing beam on the recording medium without applying any voltage to the recording medium and then, reproducing information depending on whether fluorescence has been produced.
Claim 3
Dependent Claim
33 words
The optical information recording/reproducing system as claimed in Claim 1, wherein the photoconductive layer is formed of a material selected from the group consisting of amorphous Si-Ge:H, µC-Si, Se-base materials and amorphous Si:H.
Claim 4
Dependent Claim
19 words
The optical information recording/reproducing system as claimed in Claim 2, wherein the photoconductive layer is formed of amorphous Si-Ge:H.
Claim 5
Dependent Claim
23 words
The optical information recording/reproducing system as claimed in Claim 1, wherein the thickness of the photoconductive layer is 200 Å - 10,000 Å.
Claim 6
Dependent Claim
23 words
The optical information recording/reproducing system as claimed in Claim 4, wherein the thickness of the photoconductive layer is 400 Å - 2,000 Å.
Claim 7
Dependent Claim
51 words
The optical information recording/reproducing system as claimed in Claim 1, wherein the resistivity of the photoconductive layer is 10 14 Ω·cm - 10 9 Ω·cm while unexposed to the optical recording or reproducing beam and 10 8 Ω·cm - 10 4 Ω·cm upon exposure to the optical recording or reproducing beam.
Claim 8
Dependent Claim
115 words
The optical information recording/reproducing system as claimed in Claim 1, wherein the fluorescent substance of the recording-bit producing layer is selected from the group consisting of Eu-activated Y 2 O 3 , Fe-activated LiAlO 2 , Tb/Ce-activated Y 2 SiO 5 , Ag-activated ZnS, Cu-activated ZnS, Eu-activated Y 2 0 2 S, Er-activated YF 3 , Ho-activated YF 3 , Tm-activated YF 3 , Er-activated LaF 3 , Tm-activated LaF 3 , Er-activated YOC1, Ho-activated YOC1, Er-activated Y 3 OCl 7 , Ho-activated Y 3 OCl 7 , Er-activated Y 2 0 31 Er-activated Y 2 0 2 S, Ce-activated Y 2 SiO 5 , Eu-activated YV0 4 and Tb-activated Y 2 SiO 5 .
Claim 9
Dependent Claim
36 words
The optical information recording/reproducing system as claimed in Claim 7, wherein the fluorescent substance of the recording-bit producing layer is an infrared-to-visible conversion fluorescent substance capable of emitting visible fluorescence upon exposure to infrared excitation light.
Claim 10
Dependent Claim
34 words
The optical information recording/reproducing system as claimed in Claim 8, wherein the fluorescent substance of the recording-bit producing layer is Er-activated YF 3 , Tm-activated YF 3 or Er-activated Y 2 O 3 .
Claim 11
Dependent Claim
30 words
The optical information recording/reproducing system as claimed in Claim 1, wherein the resistivity of the fluorescent substance of the recording-bit producing layer is 10 16 Ω·cm - 10 7 Ω·cm.
Claim 12
Dependent Claim
32 words
The optical information recording/reproducing system as claimed in Claim 10, wherein the resistivity of the fluorescent substance of the recording-bit producing layer is 10 14 Ω ·cm - 10 9 Ω ·cm.
Claim 13
Dependent Claim
24 words
The optical information recording/reproducing system as claimed in Claim 1, wherein the thickness of the recording-bit producing layer is 250 A - 10,000 A.
Claim 14
Dependent Claim
24 words
The optical information recording/reproducing system as claimed in Claim 12, wherein the thickness of the recording-bit producing layer is 500 A - 1,000 A.
Claim 15
Dependent Claim
39 words
The optical information recording/reproducing system as claimed in Claim 1, wherein the light source for the optical recording and reproducing beams is selected from the group consisting of Ar-ion laser, He-Ne laser, dye lasers, YAG laser and semiconductor lasers.
Claim 16
Dependent Claim
25 words
The optical information recording/reproducing system as claimed in Claim 14, wherein the light source for the optical recording and reproducing beams is a semiconductor laser.
Claim 17
Dependent Claim
27 words
The optical information recording/reproducing system as claimed in Claim 1, wherein the wavelengths of the optical recording and reproducing beams are each 350 nm - 1,200 nm.
Claim 18
Dependent Claim
35 words
The optical information recording/reproducing system as claimed in Claim 1, wherein the light source for the optical recording and reproducing beams is a semiconductor laser, the wavelength of which is 780 nm - 850 nm.
Claim 19
Dependent Claim
22 words
The optical information recording/reproducing system as claimed in Claim 1, wherein a plurality of recording media having different fluorescence spectra are laminated.
Claim 20
Dependent Claim
93 words
The optical information recording/reproducing system as claimed in Claim 1, wherein recording of information is performed, by synchronously driving the recording optical beam and the light source for the switching circuit according to recording drive signals by the use of bias circuit and switching circuit, to effect the production of bits corresponding to the recording signals in the fluorescent substance layer, and reproduction of information is performed by radiating the reproducing optical beam on the fluorescent substance layer to generate reproducing signals, which are detected by the use of the optical reproducing system.
Claim 21
Dependent Claim
131 words
The optical information recording/reproducing system as claimed in Claim 18, wherein recording of information is performed independently in each medium of the plurality of recording media, by synchronously driving the recording optical beam and the light source for the switching circuit according to recording drive signals by the use of each bias circuit and switching circuit which function independently for each medium, respectively, to effect the production of bits corresponding to the recording signals independently in each fluorescent substance layer, and reproduction of information is performed independently in each medium of the plurality of recording media, by radiating the reproducing optical beam on each fluorescent substance layer to generate reproducing signals, which are detected independently by the use of each optical reproducing system which can discriminate a wavelength from each other.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.