US4459680A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic bubble memory cassette
Assignee: Fujitsu Ltd
•
Filing: 1981-10-28
•
Granted: 1984-07-10
•
Expires: 2001-10-28
Abstract
Abstract A magnetic bubble memory device of a cassette type including at least one magnetic bubble memory chip, a package for accommodating the chip and upper and lower cases. In the magnetic bubble memory device, two magnetic shield plates are fixed to the inner surfaces of the upper and lower cases, respectively.
Inventors
- 👤 Toshiaki Sukeda
- 👤 Shiro Naoi
- 👤 Harumi Maegawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 23:01
CPC Classifications
H; H05; H05K; H05K5/00; H05K5/02; H05K5/0256; H05K5/026; G; G11; G11C; G11C19/00; G11C19/02; G11C19/08; G11C19/085
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
142 words
A magnetic bubble memory device of a cassette type, comprising: at least one magnetic bubble memory chip and associated peripheral circuits; coils, surrounding said magnetic bubble memory chip, for generating a rotating magnetic field for said magnetic bubble memory chip; permanent magnets, each positioned on opposite sides of said magnetic bubble memory chip and outside said coils, for generating a bias magnetic field for said magnetic bubble memory chip; a magnetic shield case package, encasing said magnetic bubble memory chip, said coils and said permanent magnets, for accommodating said magnetic bubble memory chip, said coils and said permanent magnets; a printed board, fixed to said package, for mounting said package and the peripheral circuits; upper and lower cases encasing said printed board mounting said package; and two magnetic shield plates fixed to the inner faces of said upper and lower cases, respectively.
Claim 2
Dependent Claim
142 words
A magnetic bubble memory device of a cassette type, comprising: at least one magnetic bubble memory chip and associated peripheral circuits; coils, surrounding said magnetic bubble memory chip, for generating a rotating magnetic field for said magnetic bubble memory chip; permanent magnets, each positioned on opposite sides of said magnetic bubble memory chip and outside said coils, for generating a bias magnetic field for said magnetic bubble memory chip; a magnetic shield case package, encasing said magnetic bubble memory chip, said coils and said permanent magnets, for accommodating said magnetic bubble memory chip, said coils and said permanent magnets; a printed board, fixed to said package, for mounting said package and the peripheral circuits; upper and lower cases encasing said printed board mounting said package; and two magnetic shield plates fixed to the inner faces of said upper and lower cases, respectively.
Claim 3
Dependent Claim
23 words
A magnetic bubble memory device as set forth in claim 1, wherein each of said magnetic shield plates has an approximately U-shaped cross-section.
Claim 4
Dependent Claim
23 words
A magnetic bubble memory device as set forth in claim 2, wherein said U-shaped magnetic shield plates are superposed at the ends thereof.
Claim 5
Dependent Claim
21 words
A magnetic bubble memory device as set forth in claim 1, wherein said magnetic shield plates are made of a permalloy.
Claim 6
Dependent Claim
22 words
A magnetic bubble memory device as set forth in claim 1, wherein said magnetic shield plates are made of substantially pure iron.
Claim 7
Dependent Claim
26 words
A magnetic bubble memory device as set forth in claim 1, wherein said upper and lower cases are made of a mixture containing a carbon material.
Claim 8
Dependent Claim
35 words
A magnetic bubble memory device as set forth in claim 1, wherein both said upper and lower cases have outer surfaces, and the outer surfaces of said upper and lower cases are coated with metal.
Claim 9
Dependent Claim
175 words
A magnetic bubble memory device of a cassette type, comprising: at least one magnetic bubble memory chip and associated peripheral circuits; coils, surrounding said magnetic bubble memory chip, for generating a rotating magnetic field for said magnetic bubble memory chip; permanent magnets, each positioned on opposite sides of said magnetic bubble memory chip and outside said coils, for generating a bias magnetic field for said magnetic bubble memory chip; a package, encasing said magnetic bubble memory chip, said coils and said permanent magnets, for accommodating said magnetic bubble memory chip, said coils and said permanent magnets; a printed board, fixed to said package, for mounting said package and the peripheral circuits; upper and lower cases encasing said printed board mounting said package and each having apertures; and two magnetic shield plates fixed to the inner faces of said upper and lower cases, respectively, each of said magnetic shield plates has an outer surface and said upper and lower case exposing the outer surfaces of said magnetic shield plates to the open air through the apertures.
Claim 10
Dependent Claim
175 words
A magnetic bubble memory device of a cassette type, comprising: at least one magnetic bubble memory chip and associated peripheral circuits; coils, surrounding said magnetic bubble memory chip, for generating a rotating magnetic field for said magnetic bubble memory chip; permanent magnets, each positioned on opposite sides of said magnetic bubble memory chip and outside said coils, for generating a bias magnetic field for said magnetic bubble memory chip; a package, encasing said magnetic bubble memory chip, said coils and said permanent magnets, for accommodating said magnetic bubble memory chip, said coils and said permanent magnets; a printed board, fixed to said package, for mounting said package and the peripheral circuits; upper and lower cases encasing said printed board mounting said package and each having apertures; and two magnetic shield plates fixed to the inner faces of said upper and lower cases, respectively, each of said magnetic shield plates has an outer surface and said upper and lower case exposing the outer surfaces of said magnetic shield plates to the open air through the apertures.
Claim 11
Dependent Claim
31 words
A magnetic bubble memory device as set forth in claim 8, further comprising heat dissipating means fixed to said magnetic shield plate fixed to said upper case and contacting said package.
Claim 12
Dependent Claim
24 words
A magnetic bubble memory device as set forth in claim 9, wherein said heat dissipating means comprises a plate made of a heat-conductive material.
Claim 13
Dependent Claim
23 words
A magnetic bubble memory device as set forth in claim 9, wherein said heat dissipating means comprises fins made of a heat-conductive material.
Claim 14
Dependent Claim
20 words
A magnetic bubble memory device as set forth in claim 10 or 11, wherein said heat conductive material is aluminium.
Claim 15
Dependent Claim
21 words
A magnetic bubble memory device as set forth in claim 10 or 11, wherein said heat-conductive material is an aluminium alloy.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-07-10 | 1988-01-09 | 1988-07-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-07-10 | 1992-01-09 | 1992-07-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-07-10 | 1996-01-09 | 1996-07-10 | $7700.00 | Window Closed / Lapsed |