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There appear to be some really interesting technologies on the horizon for printed circuits being driven by increasing needs for miniaturization and higher speeds. I wonder if anyone has an opinion on any of these questions:

How are the needs for optical and opto-electric circuits being addressed by the PWB community?

Will circuits continue to get thinner, denser, lower dielectric constant, etc, to the point where rigid and flex circuits are driven to become one and the same?

Is it possible that so many functions get integrated onto single chips that there is no need to have supercircuits to interconnect to them?

Care to speculate?

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Vitreous Humor
"Eye can see clearly now..."

Regarding the miniaturization of circuitry. While the microcircuit world continues to shrink, the real world does not. Microcircuit interconnects will continue to shrink and become more dense. However, such devices will still need to be connected to other electronic and electrical devices of normal physical size that they monitor and control. Hence, we will still require conventional interconnect circuits (hard board, flex, cable, etc.) to connect between the micro world and the world we live and function in.

I cannot see boards and flex evolving into the same product for the simple reasons that flex must flex, and boards should not! In most board applications the mechanical rigidity of the board is required to support itself and its components, many times with little additional support available. Flexing can wreak havoc with surface mount areas.

Of more interest is how flex can continue to remain flexible with the thicker substrates required of high speed applications. In many multilayers this results in excessive stiffness. These concerns are why rigid flex will continue to have a place in the market, with it's ability to "specialize" areas of the design.

While there will continue to be needs for true rigid board designs, muti-layer flex circuit designs can mimic many rigidflex properties. As surface mount components shrink in size the impact of flexure is minimized and as flex circuit thickness increases so does its rigidity. So, an argument can be made for substitution in the right case.

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Not everything that counts can be counted, and not everything that can be counted counts. - Albert Einstein (trad.)

Star_E

I am approaching the flex circuit not so much as a flexible PCB but as an extremely thin PCB that happens to be flexible which creates problems when applying components. My interest lies in the use of rigid structures where available as the source of mechanical rigidity and stability, and only after the PCB has been stabalized would parts be assembled on it.

Of special interest is the potential use of the flex PCB as an applique to an existing PCB. One side of the flex would mate electrically to a rigid PCB, route signals to the opposite using as many layers as required, and offering access to the signals on the outer side of the flex as pads for attaching parts or spring connector contact.

I am not new to the high end flex world, as I have followed it since the early days of the industry, but have not had to use the technology often so have little real experience.