US4729161A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of manufacturing a magnetic head
Assignee: US Philips Corp
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Filing: 1986-11-03
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Granted: 1988-03-08
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Expires: 2006-11-03
Abstract
Abstract A magnetic head (1) includes a core of a magnetic material having two parts (2, 3) spaced apart from each other to form a non-magnetic transducing gap (4) which is bounded on one side by a winding aperture (5) extending in the gap-bounding surface of at least one of the core parts and narrowing towards the transducing gap. To produce an accurate gap dimension the part of the winding aperture (5) immediately adjoining the transducing gap (4) is formed by a channel (6, 13, 20, 21, 32, 33) of a defined depth. The channel is formed in the gap-bounding surface of the core parts by means of an etching process. During the etching of the channels polishing marks may be simultaneously produced, the polishing marks serving as guides for subsequent grinding/polishing stages in the production of the magnetic head.
Inventors
- 👤 Johannes P. M. Verbunt
- 👤 Wilibrordus G. M. Van Den Hoek
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 03:48
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/127; G11B5/187; G11B5/23; G11B5/232; G11B5/1871; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49002; Y10T29/4902; Y10T29/49021; Y10T29/49032; Y10T29/49036; Y10T29/49037; Y10T29/49048; Y10T29/49052
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
170 words
A method of manufacturing a magnetic head of the type comprising two core parts which form a tape contact face, each core part having a gap bounding surface, said gap bounding surfaces being spaced to form a transducing gap therebetween, said method comprising the following steps: etching a channel in the gap bounding surface of one of said core parts, said channel having a floor bounded on one side by a wall, etching a polishing mark in said one of said core parts, said polishing mark being spaced a predetermined distance from a line colinear with said one wall of said channel, forming a winding aperture in said channel, said winding aperture having an edge spaced from said one wall, bonding said core parts together to form a magnetic head having a transducing gap of desired length, and grinding the tape contact face opposite said gap from said channel using said polishing mark to control the distance between said tape contact face and said one wall defining the gap height.
Claim 2
Independent Claim
170 words
A method of manufacturing a magnetic head of the type comprising two core parts which form a tape contact face, each core part having a gap bounding surface, said gap bounding surfaces being spaced to form a transducing gap therebetween, said method comprising the following steps: etching a channel in the gap bounding surface of one of said core parts, said channel having a floor bounded on one side by a wall, etching a polishing mark in said one of said core parts, said polishing mark being spaced a predetermined distance from a line colinear with said one wall of said channel, forming a winding aperture in said channel, said winding aperture having an edge spaced from said one wall, bonding said core parts together to form a magnetic head having a transducing gap of desired length, and grinding the tape contact face opposite said gap from said channel using said polishing mark to control the distance between said tape contact face and said one wall defining the gap height.
Claim 3
Dependent Claim
28 words
A method as in claim 1, wherein said one of said core parts is manufactured from a core block, said polishing mark being etched in said core block.
Claim 4
Dependent Claim
31 words
A method as in claim 2 wherein said polishing mark is defined by etching thereabout, said polishing mark remaining as a stand-off above the level of the floor of said channel.
Claim 5
Dependent Claim
47 words
A method as in claim 2 wherein said polishing mark is shaped substantially as a triangle with an apex toward said channel, whereby said polishing mark will disappear upon sufficient grinding of a tape contact face, said one wall and said tape contact face bounding said gap.
Claim 6
Dependent Claim
27 words
A method as in claim 2 wherein the polishing mark is spaced from said line by a distance corresponding to the desired height of the transducing gap.
Claim 7
Dependent Claim
19 words
A method as in claim 2 wherein the polishing mark and the channel are formed by reactive ion etching.
Claim 8
Dependent Claim
53 words
A method as in claim 2 wherein a plurality of said one of said core parts are formed in a single body having islands standing off from said gap bounding surface, said islands each having an edge defining said one wall, said edges being colinear, each polishing mark lying between two adjacent walls.
Claim 9
Dependent Claim
27 words
A method as in claim 2 wherein said polishing mark comprises a polishing channel spaced from said one wall, the distance therebetween defining the desired gap height.
Claim 10
Dependent Claim
26 words
A method as in claim 8 wherein said channel is filled with conductive material, said conductive material being ground away to reach the desired gap height.
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) | 1991-03-08 | 1991-09-07 | 1992-03-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-03-08 | 1995-09-07 | 1996-03-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-03-08 | 1999-09-07 | 2000-03-08 | $7700.00 | Window Closed / Lapsed |