US4456975A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic bubble memory device with guardrail
Assignee: Hitachi Ltd
•
Filing: 1982-02-04
•
Granted: 1984-06-26
•
Expires: 2002-02-04
Abstract
Abstract The magnetic bubble memory device according to this invention comprises an active magnetic bubble memory region formed by implanting ions into a layer of magnetic bubble material, a propagation loop having inner and outer propagation tracks formed by ion implantation so as to surround this region and to propagate captured magnetic bubbles along the circumference of this region, and at least one opening portion provided at the propagation loop so as to propagate magnetic bubbles in the inner propagation track to the outer propagation track.
Inventors
- 👤 Ryo Suzuki
- 👤 Naoki Kodama
- 👤 Tadashi Ikeda
- 👤 Yutaka Sugita
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 19:00
CPC Classifications
G; G11; G11C; G11C19/00; G11C19/02; G11C19/08; G11C19/0808; G11C19/0816
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
86 words
A magnetic bubble memory device comprising: an active magnetic bubble memory region formed by implanting ions into a layer of magnetic bubble material; a propagation loop having inner and outer propagation tracks formed by ion implantation, so as to surround said region and to propagate captured magnetic bubbles along the circumference of said region; and at least one opening portion constituting a merge track and provided at said propagation loop so as to propagate magnetic bubbles in said inner propagation track to said outer propagation track.
Claim 2
Dependent Claim
86 words
A magnetic bubble memory device comprising: an active magnetic bubble memory region formed by implanting ions into a layer of magnetic bubble material; a propagation loop having inner and outer propagation tracks formed by ion implantation, so as to surround said region and to propagate captured magnetic bubbles along the circumference of said region; and at least one opening portion constituting a merge track and provided at said propagation loop so as to propagate magnetic bubbles in said inner propagation track to said outer propagation track.
Claim 3
Dependent Claim
22 words
A magnetic bubble memory device according to claim 1, wherein said outer propagation track has a portion incapable of propagating magnetic bubbles.
Claim 4
Dependent Claim
20 words
A magnetic bubble memory device according to claim 1, wherein said opening portion faces one of three magnetic easy axes.
Claim 5
Dependent Claim
30 words
A magnetic bubble memory device according to claim 1, wherein the distance of said opening portion is 0.5 to two times the diameter of a magnetic bubble to be propagated.
Claim 6
Dependent Claim
24 words
A magnetic bubble memory device according to claim 1, wherein said inner and outer propagation tracks have undulating portions for propagating magnetic bubbles therealong.
Claim 7
Dependent Claim
62 words
A magnetic bubble memory device according to claim 1, wherein said inner and outer propagation tracks are joined in at least two places by contiguous portions, the contiguous portions being spaced from each other to define said opening portion whereby magnetic bubbles travelling in a predetermined direction adjacent one contiguous portion will jump across said opening portion to the other contiguous portion.
References Cited (Backward Citations)
US4283776A
Cited
US4263662A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-06-26 | 1987-12-26 | 1988-06-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-06-26 | 1991-12-26 | 1992-06-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-06-26 | 1995-12-26 | 1996-06-26 | $7700.00 | Window Closed / Lapsed |