Electronic control unit

Details Electronic control unit Electronic control unit

2001-12-21

2002-12-31

Martin, David (Department: 2841)

Electricity: electrical systems and devices

Housing or mounting assemblies with diverse electrical...

For electronic systems and devices

C361S749000, C361S736000

Reexamination Certificate

active

06501661

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates generally to automotive electronic control units, and, in particular, to use of a flexible circuit that is bent in the assembly of an automotive electronic control unit.
BACKGROUND OF THE INVENTION
Engine mounted electronic control units for automotive engines are disposed in a confined space in an environment subject to high ambient temperatures and extreme vibrations. Typically, in order to enhance thermal performance protect against engine vibrations, a printed circuit board that includes control circuitry is affixed to a rigidizer that may be bent to produce a reduced size module and that also functions as a heat spreader. For example, in a direct engine mount application where a Polybent™ printed circuit board, that is a printed circuit board that has a flexible circuit that is bent, is used for packaging an electronic control unit, the printed circuit board is mounted to an aluminum rigidizer. The rigidizer provides mechanical support for the printed circuit board and assists in the dissipation of heat generated by components on the printed circuit board, which heat is conductively transferred from the components to the underlying rigidizer.
Referring now to
FIGS. 1 and 2
, an electronic control unit (ECU)
100
of the prior art is illustrated.
FIG. 1
is an isometric perspective of an end view of electronic control unit
100
.
FIG. 2
is a cross-sectional side view of electronic control unit
100
. Electronic control unit
100
includes a flexible printed circuit board
104
, such as a Polybent™ printed circuit board, that is affixed to a rigidizer
106
by use of a pressure sensitive adhesive (PSA) tape, or film,
202
. Typically, circuit board
104
has a number of electronic components
102
mounted on the surface of the circuit board. Adhesive
202
is disposed between rigidizer
106
and printed circuit board
104
and functions to secure the printed circuit board to the rigidizer. After being secured to the rigidizer, the printed circuit board is essentially folded in half, resulting in a folded printed circuit board consisting of two main partitions
204
,
208
facing each other and connected to each other by a ‘W’-shaped, or serpentine, flexible circuit
206
with a radius of curvature
210
bend that is typically approximately 1 millimeter (mm). For example, circuit substrate
104
may be bent using a Polybent™ process, as described in U.S. Pat. No. 5,998,738, the text of which is hereby incorporated by reference herein.
As the functionality of electronic control units has increased over time, the corresponding circuitry has become increasingly dense and complex. As a result, electronic control units have been migrating from the use of two-layer printed circuit boards, such as printed circuit board
104
, to the use of four-layer printed circuit boards. One result of the manufacturing process of four-layer printed circuit boards is a thicker flexible circuit
206
, even when the flexible circuit remains a two-layer circuit. Due to the thicker flexible circuit
206
, flexible circuit boards are now known to crack and split when bent, resulting a control module that must be discarded. The discarded control modules result in excessive manufacturing costs and waste, especially since the printed circuit boards must be populated with components before being folded.
Therefore, a need exists for a method and apparatus for folding a printed circuit board that will not cause splitting and cracking of the flexible circuit.


REFERENCES:
patent: 4025896 (1977-05-01), Hintze et al.
patent: 5103375 (1992-04-01), Cottingham et al.
patent: 5159751 (1992-11-01), Cottingham et al.
patent: 5170326 (1992-12-01), Meny et al.
patent: 5179501 (1993-01-01), Ocken et al.
patent: 5216581 (1993-06-01), Fisher et al.
patent: 5250845 (1993-10-01), Runyan
patent: 5265322 (1993-11-01), Fisher et al.
patent: 5386341 (1995-01-01), Olson et al.
patent: 5434362 (1995-07-01), Klosowiak et al.
patent: 5969945 (1999-10-01), Cutting et al.
patent: 5998738 (1999-12-01), Li et al.
patent: 6292370 (2001-09-01), Anderson et al.
patent: 0488193 (1995-05-01), None
patent: 0938252 (1999-08-01), None

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