US3936883A
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Magnetic bubble read/write head
Assignee: Ampex Systems Corp
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Filing: 1974-12-27
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Granted: 1976-02-03
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Expires: 1994-12-27
Abstract
Abstract Magnetic bubbles are employed to write and read digitized signals of audio, video and digital data in a magnetic medium, while circumventing the problems associated with high linear tape speed or rotary head motion. Writing is accomplished via the interaction of the bubble stray field within the write head and the magnetic medium, wherein the bubble is expanded to a select geometry within the head to provide a correspondingly higher stray field at the medium surface as required for writing therein. The bubble size prior to expanding does not generate sufficient stray field to write on the medium. Reading is accomplished via the interaction of the stray field from the magnetic history in the medium and the magnetic bubbles in the read head, utilizing an intermediate overlay pattern of high permeability material such as permalloy. In reading, the stray fields from the medium alter the positions of the bubbles in the read head, whereupon the detection of the displaced bubbles provides readout of the medium history. In both the writing and reading processes, the interaction between the medium and the bubble heads is limited to specific areas whereby adjacent bubbles in the head material neither interact with, nor are influenced by, the magnetic medium until the selected conditions are realized.
Inventors
- 👤 Clarence Herbert Heckler, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 14:31
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/48; G11B5/49; G11B5/4907; G11B5/4915; G11B5/4923; G11B5/493; G11B5/4938; G11B5/4946; H; H04; H04N; H04N5/00; H04N5/76; H04N5/78; H04N5/782
Claims Analysis
Total Claims: 38
Claim 1
Independent Claim
119 words
A bubble write head for recording information in a magnetic medium, and including a normal bias field for biasing the head to a condition which stably supports the generation and storage of single wall domains, the head comprising; write bubble platelet means disposed in recording position relative to the recording medium for selectively generating single wall magnetic domains commensurate with the information being recorded, which domains generate stray fields which are insufficient to cause interaction with the magnetic medium; said bubble platelet means including integral bubble expander means for expanding the existing insufficient domains to a size sufficient to apply a write magnetic field to the medium only upon expansion of the domains, thereby to perform the write process.
Claim 2
Dependent Claim
119 words
A bubble write head for recording information in a magnetic medium, and including a normal bias field for biasing the head to a condition which stably supports the generation and storage of single wall domains, the head comprising; write bubble platelet means disposed in recording position relative to the recording medium for selectively generating single wall magnetic domains commensurate with the information being recorded, which domains generate stray fields which are insufficient to cause interaction with the magnetic medium; said bubble platelet means including integral bubble expander means for expanding the existing insufficient domains to a size sufficient to apply a write magnetic field to the medium only upon expansion of the domains, thereby to perform the write process.
Claim 3
Dependent Claim
55 words
The write head of claim 1 wherein the bubble expander means includes write bias field generating means for biasing the magnetic medium to a point on its associated saturation magnetization curve, such that the composite expanded domain stray field and the write bias field are sufficient to perform the write process on the magnetic medium.
Claim 4
Dependent Claim
56 words
The write head of claim 2 wherein the bubble expander means includes an expansion field applied in opposition to the normal bias field to allow bubble expansion in response thereto, said write magnetic field defining first binary bits in the magnetic medium, wherein the absence of domains defines the second binary bits of the write process.
Claim 5
Dependent Claim
25 words
The write head of claim 3 wherein the bubble expander means further includes means for anihilating the expanded bubbles after the write process is performed.
Claim 6
Dependent Claim
65 words
The write head of claim 3 wherein the single wall magnetic domains define magnetic bubbles, and the write bubble platelet means further includes write bubble logic circuits integrally formed therein for receiving the information to be recorded and for generating the bubbles in accordance with said information, said bubble expander means being integrally formed with the bubble logic circuits to define the bubble write head.
Claim 7
Dependent Claim
90 words
The write head of claim 5 wherein the write bubble logic circuits further comprise; a bubble generator coupled to receive the information and to generate bubbles in accordance therewith; input register means coupled to the bubble generator; write buffer register means coupled to the input register means and thence to the bubble expander means; and input buffer means coupled to the bubble generator and adapted to selectively receive and store the information when the input register means does not, and to subsequently introduce the information to the input register means.
Claim 8
Dependent Claim
46 words
The write head of claim 6 further comprising, current access circuits integral with the write bubble logic circuits and the bubble expander means to selectively propagate the bubbles through the logic circuits and into the bubble expander means for expansion thereof to perform the write process.
Claim 9
Dependent Claim
61 words
The write head of claim 5 wherein the information to be recorded is introduced to the write head in bit parallel, word serial format, wherein the write bubble logic selectively accumulates the bits to allow their serial introduction from the integral bubble expander means to the magnetic medium to record the words in side-by-side format across the width of the medium.
Claim 10
Dependent Claim
127 words
The write head of claim 2 wherein the signal wall magnetic domains define magnetic bubbles, and the bubble platelet means is formed of a bubble material; wherein the expander means further includes; a trough defining a bubble write head formed within the platelet means, said trough having a selected geometry defined by boundaries in the form of energy barriers; said write bias field generating means being disposed to bias the magnetic medium over a region thereof which is in register with the trough; wherein said trough defines the size and geometry of the expanded bubble upon energization of the write bias field generating means; and current access circuits disposed across the trough to propagate the bubble therealong in response to selective energization of the current access circuits.
Claim 11
Dependent Claim
72 words
The write head of claim 9 wherein a plurality of troughs and thus write heads are juxtaposed to define a multi-head write assembly, said write bias field generating means being disposed to bias the magnetic medium over a region thereof in register with the multi-head assembly, said current access circuits extending through all the juxtaposed troughs to simultaneously propagate therein those bubles which are generated to represent a reversed state of magnetization.
Claim 12
Dependent Claim
119 words
A bubble read head for reproducing the magnetic history recorded in a magnetic medium in the form of reversed and non-reversed states of magnetization, comprising; read bubble platelet means disposed in reproducing position relative to the magnetic medium for generating single wall magnetic domains with stray fields insufficient to affect the states of magnetization in the medium; the read bubble platelet means including integral means for restraining movement of a domain when nonresponsive to the magnetic history in the medium, and for selectively displacing the position of the domain when responsive to the magnetic history; and detector means integral with the read bubble platelet means for detecting the displaced domains to thus determine the magnetic history in the medium.
Claim 13
Dependent Claim
119 words
A bubble read head for reproducing the magnetic history recorded in a magnetic medium in the form of reversed and non-reversed states of magnetization, comprising; read bubble platelet means disposed in reproducing position relative to the magnetic medium for generating single wall magnetic domains with stray fields insufficient to affect the states of magnetization in the medium; the read bubble platelet means including integral means for restraining movement of a domain when nonresponsive to the magnetic history in the medium, and for selectively displacing the position of the domain when responsive to the magnetic history; and detector means integral with the read bubble platelet means for detecting the displaced domains to thus determine the magnetic history in the medium.
Claim 14
Dependent Claim
47 words
The read head of claim 11 wherein the integral means for restraining movement of a single wall domain includes, overlay pattern means disposed to restrain the domain therein until influenced by passage thereby of a reversed state of magnetization of the recorded magnetic history in the medium.
Claim 15
Dependent Claim
65 words
The read head of claim 12 wherein the integral means for restraining movement of a domain further includes propagating means integral therewith to selectively propagate the domains, wherein said overlay pattern means is disposed to span a gorge formed by omission of selected portions of the propagating means, said gorge preventing movement of the domain until influenced by passage of the reversed state of magnetization.
Claim 16
Dependent Claim
66 words
The read head of claim 13 wherein the single wall magnetic domains define magnetic bubbles, and the read bubble platelet means further includes read bubble logic circuits integrally formed therein for generating bubbles for introduction to the overlay pattern means, and for receiving from the latter means any bubbles displaced from their position in the overlay pattern means for subsequent detection thereof via the detector means.
Claim 17
Dependent Claim
78 words
The read head of claim 14 wherein the magnetic history is recorded in the medium as a multiplicity of words disposed in side-by-side format across the width of the medium, wherein the overlay pattern means receive respective words of the multiplicity of words in the form of serial successions of bits, wherein the read bubble logic selectively accumulates the bits to allow a bit parallel, word serial introduction thereof to the detector means to retrieve the magnetic history.
Claim 18
Dependent Claim
71 words
The head of claim 14 wherein the read bubble logic circuits further comprise; a bubble generator coupled to the overlay pattern means to selectively introduce bubbles thereto; buffer data register means coupled to the overlay pattern means to receive any displaced bubbles; output register means coupled to the buffer data register means and thence to the detector means to selectively advance information to the buffer data register means for subsequent detection.
Claim 19
Dependent Claim
38 words
The head of claim 16 further comprising, current access circuits integral with the read bubble logic circuits to selectively propagate the bubbles into, and from, the overlay pattern means in accordance with the magnetic history in the medium.
Claim 20
Dependent Claim
114 words
The head of claim 17 wherein the bubble platelet means is formed of a bubble material; wherein the overlay pattern means includes a diamond shaped read pattern formed of a high permeability (magnetic) material and defining a read head; wherein the leading half of the read pattern is formed of an open corner of the diamond shape; wherein the trailing half of the read pattern is disposed to span the gorge; and wherein passage adjacent the read pattern by the stray magnetic field of a reversed state of magnetization of the magnetic history induces magnetic poles in the pattern to displace the bubble from within the pattern region to a point beyond the gorge.
Claim 21
Dependent Claim
24 words
the head of claim 18 wherein the bubble is displaced in a straight line direction along the direction of travel of the magnetic medium.
Claim 22
Dependent Claim
48 words
The head of claim 19 wherein a plurality of read patterns and thus read heads are juxtaposed to define a multihead read assembly, said current access circuits extending through all the juxtaposed patterns to simultaneously propagate those bubbles therein which are displaced by the reversed state of magnetization.
Claim 23
Dependent Claim
114 words
A bubble write/read head for use in association with a magnetic medium comprising the combination of; first bubble platelet means for generating expanded bubbles of size sufficient to apply a write magnetic field of the medium in the form of a reversed state of magnetization, wherein the presence and absence of expanded bubbles defines an image of the information being recorded as the magnetic history in the medium; and second bubble platelet means for generating bubbles therein, and including restraining means for displacing the position of selected bubbles in accordance with the reversed states of magnetization previously recorded, to provide regeneration, detection and thus readout of the image of the information in the medium.
Claim 24
Dependent Claim
114 words
A bubble write/read head for use in association with a magnetic medium comprising the combination of; first bubble platelet means for generating expanded bubbles of size sufficient to apply a write magnetic field of the medium in the form of a reversed state of magnetization, wherein the presence and absence of expanded bubbles defines an image of the information being recorded as the magnetic history in the medium; and second bubble platelet means for generating bubbles therein, and including restraining means for displacing the position of selected bubbles in accordance with the reversed states of magnetization previously recorded, to provide regeneration, detection and thus readout of the image of the information in the medium.
Claim 25
Dependent Claim
69 words
The write/read head of claim 21 wherein the first bubble platelet includes means for generating a write bias field which in combination with the stray field of the expanded bubbles generates the reversed state of magnetization in the magnetic medium to define a first binary bit; wherein the absence of an expanded bubble leaves undisturbed the initial state of magnetization of the medium to define the second binary bit.
Claim 26
Dependent Claim
41 words
The write/read head of claim 22 wherein the restraining means displaces a generated bubble therein only in response to passage thereby of a reversed state of magnetization in the magnetic medium immediately upon previous recording via the first bubble platelet means.
Claim 27
Dependent Claim
80 words
The write/read head of claim 23 further including expander means integral with the first platelet in the form of a trough defining a write head for selectively receiving a bubble, said means for generating a write bias field being disposed to decrease the magnetic field seen by the bubble within the trough to provide expansion of the bubble to a size to provide the reversed state of magnetization over an area of the magnetic medium in register with the trough.
Claim 28
Dependent Claim
71 words
The write/read head of claim 24 wherein the restraining means includes; a read overlay pattern integral with the second bubble platelet to define a read head in-line with the trough of the write head; wherein the bubble is generated within the read overlay pattern; and wherein the passage of the reversed state of magnetization adjacent the read overlay pattern induces magnetic poles therein to displace the bubble therefrom for subsequent detection.
Claim 29
Dependent Claim
121 words
A process for magnetically writing information with a bubble head in association with a magnetic medium, comprising the steps of; applying a normal bias field to the head to allow it to stably support the generation and storage of stable magnetic bubbles adjacent the medium generating the stable magnetic bubbles in selected regions of the head to represent a first binary bit of the information; wherein failing to generate magnetic bubbles in other selected regions of the head represents the second binary bit of the information, and expanding the generated bubbles to a selected size and geometry to apply a magnetic write field to corresponding portions of the medium of sufficient magnitude to write the first binary bit on the medium.
Claim 30
Dependent Claim
121 words
A process for magnetically writing information with a bubble head in association with a magnetic medium, comprising the steps of; applying a normal bias field to the head to allow it to stably support the generation and storage of stable magnetic bubbles adjacent the medium generating the stable magnetic bubbles in selected regions of the head to represent a first binary bit of the information; wherein failing to generate magnetic bubbles in other selected regions of the head represents the second binary bit of the information, and expanding the generated bubbles to a selected size and geometry to apply a magnetic write field to corresponding portions of the medium of sufficient magnitude to write the first binary bit on the medium.
Claim 31
Dependent Claim
100 words
The process of claim 26 wherein the step of expanding the bubbles further includes; biasing the medium to a point just below the knee of the saturation magnetization curve; and applying a bubble expander field in a direction opposed to the normal bias field to allow the bubbles to expand in size, whereby the write bias field in conjunction with the stray field from the expanded bubble provides the composite write field which reverses the state of the magnetization in the medium over the region in register with the expanded bubble; and anihilating the expanded bubbles after the write process.
Claim 32
Dependent Claim
64 words
The process of claim 27 wherein the step of biasing the medium includes; applying a write bias field in the plane of the medium opposite to the magnetization during the write process; and the step of applying a bubble expander field includes; applying current to a conductor bounding the bubbles to generate a field which opposes the normal bias field during the write process.
Claim 33
Dependent Claim
77 words
A process for reading the magnetic history in a magnetic medium with a bubble head, comprising the steps of; selectively generating stable magnetic bubbles within the bubble head and adjacent the medium, which bubbles have stray fields insufficient to affect the magnetic history; selectively restraining and displacing the bubbles in response to the magnetic history to generate an image thereof within the bubble head; and detecting the displaced bubbles to reconstruct the image of the magnetic history.
Claim 34
Dependent Claim
77 words
A process for reading the magnetic history in a magnetic medium with a bubble head, comprising the steps of; selectively generating stable magnetic bubbles within the bubble head and adjacent the medium, which bubbles have stray fields insufficient to affect the magnetic history; selectively restraining and displacing the bubbles in response to the magnetic history to generate an image thereof within the bubble head; and detecting the displaced bubbles to reconstruct the image of the magnetic history.
Claim 35
Dependent Claim
75 words
The process of claim 29 wherein the step of selectively generating further includes; applying a normal bias field to the head to provide the stable magnetic bubbles; wherein the step of selectively restraining and displacing the bubbles includes; restraining the bubbles within selected regions of the head in register with respective magnetic history in the medium; and releasing those bubbles which are affected by given portions of the magnetic history to allow their subsequent detection.
Claim 36
Dependent Claim
31 words
The process of claim 30 wherein the step of detecting further includes; propagating the released bubbles to respective regions of detection; and expanding the propagated bubbles to allow their ready detection.
Claim 37
Dependent Claim
82 words
A bubble head for processing information in association with a magnetic recording medium comprising the combination of; means for introducing the information to be recorded to the head in bit parallel, word serial format; and bubble logic means for selectively accumulating the bits to allow the serial introduction thereof from the head, to record the words in side-by-side relation across the width of the magnetic medium such that similar bits of each of the words form respective transverse lines across the medium.
Claim 38
Dependent Claim
82 words
A bubble head for processing information in association with a magnetic recording medium comprising the combination of; means for introducing the information to be recorded to the head in bit parallel, word serial format; and bubble logic means for selectively accumulating the bits to allow the serial introduction thereof from the head, to record the words in side-by-side relation across the width of the magnetic medium such that similar bits of each of the words form respective transverse lines across the medium.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-02-02 | 1979-08-04 | 1980-02-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-02-02 | 1983-08-04 | 1984-02-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-02-02 | 1987-08-04 | 1988-02-03 | $7700.00 | Window Closed / Lapsed |