Low inductance, ferrite sub-gap substrate structure for surface film magnetic recording heads

• US 6,496,328 B1
• Filed: 12/30/1999
• Issued: 12/17/2002
• Est. Priority Date: 12/30/1999
• Status: Expired due to Term

• Current Assignee: Minnesota Tape Ventures, LLC
• Original Assignee: Advanced Research Corporation
• Inventors: Dugas, Matthew P.
• Primary Examiner(s): KLIMOWICZ, WILLIAM JOSEPH
• Application Number:
  US09/475,420
• Time in Patent Office: 1,083 Days
• Field of Search: 360/127, 360/125, 360/121, 360/110, 360/119, 360/122, 360/123
• US Class Current: 360/121
• CPC Class Codes: G11B 20/1211 with different data track configurations longitudinal control tracks with transverse user data tracks G11B20/1207
• CPC Class Codes: G11B 20/1217 on discs
• CPC Class Codes: G11B 5/127 Structure or manufacture of heads, e.g. inductive
• CPC Class Codes: G11B 5/1276 including at least one magnetic thin film
• CPC Class Codes: G11B 5/193 the pole pieces being ferrite or other magnetic particles G11B5/1871 takes precedence; in thin film G11B5/31
• CPC Class Codes: G11B 5/23 Gap features G11B5/1871, G11B5/1875, G11B5/265, G11B5/29, G11B5/488 and subgroups, G11B5/4907 and subgroups, G11B5/4969 and subgroups take precedence
• CPC Class Codes: G11B 5/232 Manufacture of gap
• CPC Class Codes: G11B 5/235 Selection of material for gap filler G11B5/232 takes precedence
• CPC Class Codes: G11B 5/29 Structure or manufacture of unitary devices formed of plural heads for more than one track G11B5/33, G11B5/49 and subgroups take precedence; in thin film structure G11B5/31
• CPC Class Codes: G11B 5/295 Manufacture
• CPC Class Codes: G11B 5/3116 Shaping of layers, poles or gaps for improving the form of the electrical signal transduced, e.g. for shielding, contour effect, equalizing, side flux fringing, cross talk reduction between heads or between heads and information tracks G11B5/3113, G11B5/245 take precedence
• CPC Class Codes: G11B 5/4893 relative to moving tape
• CPC Class Codes: G11B 5/584 for track following on tapes
• CPC Class Codes: Y10T 29/49055 with bond/laminating preformed parts, at least two magnetic
• CPC Class Codes: Y10T 29/49057 Using glass bonding material

Abstract

A thin film magnetic recording head is fabricated by forming a substrate from opposing ferrite blocks which have a ceramic member bonded between them. This structure is then diced to form a plurality of columns, wherein each column has a ferrite/ceramic combination. Each column represents a single channel in the completed head. A block of ceramic is then cut to match the columned structure and the two are bonded together. The bonded structure is then cut or ground until a head is formed, having ceramic disposed between each channel. A ferrite back-gap is then added to each channel, minimizing the reluctance of the flux path. The thin film is patterned on the head to optimize various channel configurations.

Claims

1. A multi-channel surface film timing-based magnetic recording head comprising:

a plurality of magnetically permeable columns, each column being divided into two parts by a substantially magnetically impermeable gap member, the gap member forming a sub-gap on a writing side of the head;

at least one magnetically impermeable barrier, located between and magnetically isolating the plurality of magnetically permeable columns from one another; and

a magnetically permeable thin film layer spanning at least a portion of the sub-gap and magnetically coupling the two parts of each column, wherein the thin film layer includes writing gaps defining a timing-based pattern.

2. The magnetic recording head of claim 1, further comprising:

a plurality of magnetically permeable back-bars, wherein each magnetically permeable column has a back-bar coupled to it and the back-bar bypasses the magnetically impermeable gap member at one end of the magnetically permeable column.

3. The magnetic recording head of claim 2, wherein each back-bar is a substantially U shaped ferrite block.

4. The magnetic recording head of claim 2, wherein a single set of windings are wrapped around all of the back bars providing a single coil that drives all of the back bars.

5. The magnetic recording head of claim 2, further comprising

a plurality of coils wherein each back-bar has a separate single coil wrapped about it.

6. The magnetic recording head of claim 1 wherein the magnetically impermeable barrier is ceramic.

7. The magnetic recording head of claim 1 wherein the thin film layer is located over an entire upper surface of the recording head.

8. The magnetic recording head of claim 1 wherein the thin film layer is located only over a portion of the recording head, the portion being the area between air bleed slots cut into the head.

9. The magnetic recording head of claim 1 wherein the thin film layer has been removed in portions so as to magnetically isolate each of the magnetically permeable columns.

10. A surface film magnetic recording head having a timing based pattern, the recording head comprising:

a magnetically permeable core;

a substantially magnetically impermeable member dividing the core into two poles and forming a sub-gap;

at least one magnetically impermeable barrier dividing the core and the impermeable member into a plurality of channels; and

a magnetically permeable thin film coupling the two poles across the sub-gap, wherein the thin film includes writing gaps forming a timing based pattern.

11. The surface film magnetic recording head of claim 10, further comprising:

a back-bar, formed from magnetically permeable material, the back bar bypassing the impermeable member to complete a magnetic circuit between the two poles.

12. The surface film magnetic recording head of claim 11 wherein a separate back-bar is provided for each channel.

13. The surface film magnetic recording head of claim 12 wherein each channel is magnetically isolated.

14. The surface film magnetic recording head of claim 10 wherein each channel is magnetically isolated.

15. The surface film magnetic recording head of claim 10 wherein the thin film covers an entire upper surface of the head.

16. The surface film magnetic recording head of claim 10 wherein the thin film is only located within an area on an upper surface of the head defined by the width of the head and between sets of air bleed slots, so as to include coverage of the sub-gap.

17. The surface film magnetic recording head of claim 16 wherein a space between each channel is devoid of the thin film, the space extending over the entire length of the head.

18. The surface film magnetic recording head of claim 10 wherein a space between each channel is devoid of the thin film, the space extending over the entire length of the head.