Flexible circuit with partial ground path

Patent metadata

Field	Value
Publication number	US-9681542-B2
Application number	US-201414541843-A
Country	US
Kind code	B2
Filing date	Nov 14, 2014
Priority date	Nov 14, 2014
Publication date	Jun 13, 2017
Grant date	Jun 13, 2017

Abstract

A head assembly for a magnetic tape storage device includes a head and a flexible circuit connected to the head. The flexible circuit includes a gripping portion, an end including electrical contacts for the head, conductors extending from the electrical contacts, and ink patterned onto the electrical contacts and gripping portion to form electrical paths therebetween. The ink conducts electrostatic charge from the electrical contacts and conductors to a grounded user in response to skin of the user contacting the ink.

First claim

What is claimed is:

1. A magnetic tape storage device comprising:
a head assembly including a head and flexible circuit connected to the head, wherein the flexible circuit includes an end including electrical contacts for the head, a gripping portion defined by flared edge portions of the flexible circuit before the end, conductors extending from the electrical contacts, and ink patterned onto the electrical contacts and gripping portion to form electrical paths of predefined shape therebetween to conduct electrostatic charge from the electrical contacts and conductors to a grounded user in response to skin of the grounded user contacting the ink, wherein the ink has a conductivity less than a conductivity of the electrical contacts but greater than a conductivity of insulating layers of the flexible circuit and wherein the electrical paths have dimensions that are based on the conductivity of the ink such that resistance between the electrical contacts and gripping portion falls within a predefined target range.

2. The magnetic tape storage device of claim 1 , wherein the ink is a silk screen ink.

3. The magnetic tape storage device of claim 1 , wherein the resistance is at least 100 kΩ.

4. A head assembly for a magnetic tape storage device comprising:
a head; and
a flexible circuit connected to the head and including an end having electrical contacts for the head, a gripping portion defined by flared edge portions of the flexible circuit before the end, conductors extending from the electrical contacts, and traces of predefined shape extending between some of the electrical contacts and gripping portion, wherein a material of the traces has a conductivity less than a conductivity of the electrical contacts but greater than a conductivity of insulating layers of the flexible circuit and wherein the traces have dimensions that are based on the conductivity of the material such that resistance between the electrical contacts and gripping portion falls within a predefined target range.

5. The assembly of claim 4 , wherein the material is an ink.

6. The assembly of claim 5 , wherein the ink is a silk screen ink.

7. The assembly of claim 4 , wherein the material forms part of the gripping portion.

8. The assembly of claim 4 , wherein the traces touch every other one of the electrical contacts.

9. The assembly of claim 4 , wherein the predefined target range includes 1 MΩ.

10. A flexible circuit comprising:
a substrate having electrical pads and conductors on an end thereof, and flared edge portions defining a handling portion before the end, wherein each of the conductors extends from one of the electrical pads; and
ink layered onto the substrate in a pattern having a predefined shape that contacts some of the electrical pads and covers some of the handling portion such that contact between skin of a grounded user and the ink causes electrostatic charge carried by the electrical pads or conductors to pass to the grounded user via the ink, wherein the ink has a conductivity less than a conductivity of the electrical pads but greater than a conductivity of insulating layers associated with the substrate and wherein the shape has dimensions that are based on the conductivity of the ink such that resistance between the electrical pads and tripping portion falls within a predefined target range.

11. The circuit of claim 10 , wherein the ink is a silk screen ink.

12. The circuit of claim 10 , wherein the ink is in contact with every other one of the electrical pads.

13. The circuit of claim 10 , wherein the resistance is at least 100 kΩ.

Assignees

• Oracle Int Corp

Inventors

• Ziegler Karl
• Mckinstry Kevin D

Classifications

• H05F3/00

  Carrying-off electrostatic charges ({from shoes A43B7/36}; from living beings A61N1/14; {from tyres B60C19/08; from vehicles B60R16/06; from aircraft B64D45/02; from large containers B65D90/46}) · CPC title

• H05K1/118

  specially for flexible printed circuits, e.g. using folded portions · CPC title

• G11B5/40

  Protective measures on heads, e.g. against excessive temperature  (G11B5/31 takes precedence; protection against wear G11B5/255  {; protective structure of the head: see under structures, e.g. G11B5/3106}) · CPC title

• G11B5/6094

  Preventing or discharging electrostatic charge build-up on the flying head · CPC title

• G11B33/1493

  Electro-Magnetic Interference [EMI] or Radio Frequency Interference [RFI] shielding; grounding of static charges · CPC title