US 7,439,449 B1Granted

Flexible circuit for establishing electrical connectivity with optical subassembly

AssigneeFinisar Corporation

InventorsDev E. Kumar, Giorgio Giaretta, Stefano Schiaffino, Donald A. Ice

Life of this patent

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Abstract

Flexible printed circuit boards interconnect to adjacent electronic devices through one or more of high speed data, low speed data, high current, and ground lines and pads. The design of the high speed data pads and traces and adjacent ground pads and traces maintains a desired impedance in the flexible circuit and at the transition from the flexible circuit to a printed circuit board, a ceramic header, or other device to ensure high speed operation. The pads are preferably arranged in a two dimensional geometry such that a connecting area of the flexible circuit is narrower than it would preferably be if the pads were arranged linearly. The two dimensional array also allows the use of the high current thermoelectric cooler pads, which require large surface areas that may otherwise not fit in a conventional linear array.

Claims7

Dependent claims

A flexible circuit comprising:

a flexible substrate having first and second opposing surfaces;
a first connecting area comprising a first data pad on the first surface;
a second connecting area comprising a second data pad on the first surface;
a first conductive trace on the first surface of the flexible substrate, the first conductive trace conductively connecting the first data pad to the second data pad;
and
a ground trace on the second surface of the flexible substrate and having at least one contact pad on at least one of the first connecting area and the second connecting area, the ground trace having a portion that is adjacent to but not in contact with at least one of the first data pad and the second data pad, wherein the ground trace connects through the flexible substrate to ground pads on the first surface, the ground pads positioned on both sides of the first conductive trace such that the ground trace and the ground pads wrap around the first conductive trace, wherein the ground trace is arranged to maintain an impedance by producing a controlled amount of capacitance that compensates for inductance associated with coming up from the ground trace or through the flexible substrate.

3 more elements

Dependencies are inferred from the claim text.

Facts

Application: 10/409,837Filed 9 Apr 2003 · continuation in part
Priority: 14 Feb 2002
Granted: 21 Oct 2008
Term ends: Not estimatedThe source records don’t support an estimate.

Classification19 codes

H05K 1/0253
Impedance arrangements, e.g. impedance matching, reduction of parasitic impedance: impedance adaptations of transmission lines by special lay-out…
G02B 6/4292
Coupling light guides with opto-electronic elements: the light guide being disconnectable from the opto-electronic element, e.g. mutually self…
H05K 1/147
Structural association of two or more printed circuits: at least one of the printed circuits being bent or folded, e.g. by using a flexible…
H01S 5/02212
Characterised by the shape of the housings: can-type, e.g. TO-CAN housings with emission along or parallel to symmetry axis

Family

Application10/077,067Parent of this continuation-in-part · filed 14 Feb 2002
Application10/231,395Parent of this continuation-in-part · filed 29 Aug 2002
US 6,703,561 B1Parent of this continuation-in-part
US 6,586,678 B1Parent of this continuation-in-part
US 7,439,449 B1This patent

From the US filing history. Foreign family members aren’t listed.