Capacitance controlled flexible circuit suspension

• US 6,233,122 B1
• Filed: 08/27/1999
• Issued: 05/15/2001
• Est. Priority Date: 06/15/1999
• Status: Expired due to Term

• Current Assignee: Magnecomp Corporation (TDK Corporation)
• Original Assignee: Magnecomp Corporation (TDK Corporation)
• Inventors: Summers, Robert
• Primary Examiner(s): Tupper, Robert S.
• Application Number:
  US09/384,466
• Time in Patent Office: 627 Days
• Field of Search: 360/245.9, 360/246
• US Class Current: 360/246
• CPC Class Codes: G11B 5/484 Integrated arm assemblies, e.g. formed by material deposition or by etching from single piece of metal or by lamination of materials forming a single arm/suspension/head unit
• CPC Class Codes: H05K 1/0393 Flexible materials H05K1/038 takes precedence; specific organic compositions are classified in H05K1/0313 and subgroups
• CPC Class Codes: H05K 2201/0195 Dielectric or adhesive layers comprising a plurality of layers, e.g. in a multilayer structure
• CPC Class Codes: H05K 3/0061 onto a metallic substrate, e.g. a heat sink heat sinks for electric apparatus H05K7/20

Abstract

A disk drive suspension reduces or blocks capacitive coupling between a flexible circuit electrical connector and the steel load beam by interposing a second dielectric layer not part of the flexible circuit between the flexible circuit and the load beam. The change in capacitive coupling is realized without changing the mechanical properties of the flexible circuit, which can still be used to form the suspension flexure.

Claims

1. A disk drive suspension comprising a steel load beam and an electrical connector comprising a flexible circuit comprising dielectric plastic film and trace conductors disposed thereon across an air gap to said load beam, said dielectric film being a first dielectric film and having a thickness providing said electrical connector predetermined mechanical properties but inadequate to block capacitive coupling of said trace conductors with said steel load beam across said air gap, a second dielectric film in said air gap between said load beam and said flexible circuit, said second dielectric film having a thickness adequate to block said capacitive coupling, said second dielectric film being secured between said load beam and said electrical connector, said second dielectric film being free of trace conductors, whereby capacitive coupling between said load beam and said trace conductors is blocked without increasing the thickness of said first dielectric film or varying said predetermined mechanical properties.

3. The disk drive suspension according to claim 1, in which said load beam has left and right edge rails, said electrical connector being disposed between said edge rails.

4. The disk drive suspension according to claim 1, in which said first dielectric film is a polyimide plastic film.

5. The disk drive suspension according to claim 4, in which said polyimide plastic first dielectric film has thickness of less than about 0.001 inch.

6. The disk drive suspension according to claim 1, in which said first dielectric film has thickness of less than about 0.001 inch.

7. The disk drive suspension according to claim 1, in which said second dielectric film is a polyimide plastic film, adhesively attached to said load beam.

8. The disk drive suspension according to claim 7, in which said second dielectric film has a thickness of greater than about 0.002 inch.

9. The disk drive suspension according to claim 1, in which said second dielectric film has a thickness of greater than about 0.002 inch.

10. The disk drive suspension according to claim 9, in which said second dielectric film has a thickness between about 0.002 and 0.006 inch, and is adhesively attached to the portion of the flexible circuit that is opposite to the load beam.

2. A disk drive suspension comprising a steel load beam and an electrical connector comprising a flexible circuit of a dielectric plastic film and trace conductors disposed thereon across an air gap to said load beam, said dielectric film being a first dielectric film and having a thickness providing said electrical connector predetermined mechanical properties but inadequate to block capacitive coupling of said trace conductors with said steel load beam across said air gap, said electrical conductor flexible circuit having a distal portion shaped to define a slider-supporting flexure, a second dielectric film in said air gap between said load beam and said flexible circuit, said second dielectric film having a thickness adequate to block said capacitive coupling, said second dielectric film being secured between said load beam and said electrical connector, said distal portion being free of said second dielectric. whereby capacitive coupling between said load beam and said trace conductors is blocked without increasing the thickness of said first dielectric film or varying said predetermined mechanical properties.

11. A disk drive suspension comprising a stainless steel load beam and a flexible circuit electrical connector comprising a laminate of dielectric plastic film and a plurality of trace conductor pairs disposed thereon in a capacitance zone defined by opposing portions of said load beam and said flexible circuit electrical connector, said flexible circuit connector having a distal portion beyond said capacitance zone, said dielectric film being a first dielectric film and having a thickness providing said flexible circuit electrical connector predetermined mechanical properties within and beyond said capacitance zone but inadequate to block capacitive coupling of said trace conductors with said opposing steel load beam in said capacitance zone, a second dielectric film free of trace conductors and bonded between said opposing load beam and flexible circuit electrical connector portions, said second dielectric film having a thickness adequate to block said capacitive coupling, whereby capacitive coupling between said load beam and said trace conductors is blocked without increasing the thickness of said first dielectric film or varying said predetermined mechanical properties in said flexible circuit electrical connector distal portion.

12. The disk drive suspension according to claim 11, in which said flexible circuit electrical connector distal portion is shaped to define a slider-supporting flexure, said distal portion being free of said second dielectric.

13. The disk drive suspension according to claim 12, in which said load beam has left and right edge rails, said flexible circuit electrical connector being disposed between said edge rails.

14. The disk drive suspension according to claim 13, in which said first dielectric film is a polyimide plastic film.

15. The disk drive suspension according to claim 14, in which said polyimide plastic first dielectric film has thickness of less than about 0.001 inch.

16. The disk drive suspension according to claim 15, in which said second dielectric film is a polyimide plastic film.

17. The disk drive suspension according to claim 16 in which said second dielectric film has a thickness of greater than about 0.002 inch.

18. The disk drive suspension according to claim 17, in which said second dielectric film has a thickness between about 0.002 and 0.006 inch.