Since their introduction, flexible circuits have continued a steady climb from relative obscurity to center stage in the world of electronic interconnections. Today, they are among the most popular choice for solving challenging electronic interconnection problems. Those who use this technology on a regular basis are familiar with the many reasons for the popularity of flex.
Flex circuits are thin and light; they can be bent, folded, or flexed. When challenged, they can offer superior electrical performance due in part to the different polymers used as substrates. In short, flex circuits provide highly reliable interconnection structures that make possible solutions, which cannot be achieved by any other method (at least not as easily).
With such an impressive list of benefits already available, it might seem as though flex circuit technology has already reached its limits. However, the basic principle of continuous improvement is that it does not rest. Improvement demands that we persist in our efforts to find ways to make flex circuit materials and processes still better.
President John F. Kennedy made famous the words of George Bernard Shaw: “Some people see things that are and ask, ‘Why?’ I dream things that never were and say, ‘Why not?’” It is evident from the order of his statement that Shaw appreciated the importance of first asking “Why?”
For young children, “Why?” is a hallmark question as they try to comprehend the complex world about them.
But Shaw seems to have intuited that without that important and fundamental question, the equally important question “Why not?” has no place to start. “Why not?” sparks an inventive spirit. The innovator is often very familiar with the question “Why not?” and, in many cases, has made it a touchstone for their innovations by seeing the unseen before being manifested into reality.
Indeed, innovation is commonly a product of observation and “Why and why not?” questions. Such questions press the mind into action, which hopefully results in seeing (or dreaming of, as Shaw suggests) some missing piece or the boundaries of empty space that define the missing pieces. After these mind-opening questions, the other familiar questions of who, what, when, where, and how will be required to shape and mold a solution to the initiating question.
Thus, the first challenge that confronts the innovator is to see what is not there and to turn it from a vague, dreamy concept to physical reality. How does one approach such a challenge? Let’s take a short “mind walk” to try to uncover and illuminate the missing pieces that await their moment of discovery. For this exercise, let’s apply the idea to our venerable flex circuit technology and see what it might yield.
First, it is worth noting that once we become familiar with something—no matter what its nature—we become wedded to our perceptions of it. Technology is not immune. This is a trap that humans have been falling into for ages, though some have admonished us to avoid it. Shakespeare, for example, warned us in his play Antony and Cleopatra: “Make not your thoughts your prison.” Unfortunately, it is something we are all prone to do.
Turning back to our technology—flexible circuits—it is clearly a highly enabling technology with many facets of materials, design, manufacturing, testing, etc. While the interdependence and interplay between these elements must be considered (changing one thing will typically impact another), it should not be an initial constraint. Instead, one should be unafraid and even encouraged to wander off the beaten path. There will be some blind alleys when not staying on the main streets, but these alleys can sometimes yield unexpected treasures that—while not of value to the current effort—could be useful in unrelated efforts later on.
Another thing to avoid early on is any consideration of cost. It is often the case that a process or device is expensive at the outset, but the price will come down with experience and more participants. Always be mindful of the potential to have your thoughts imprison your dreams and actions.
Those points aside, let’s now quickly apply the “Why?” question to some aspects of flexible circuit technology to see what it yields. Spoiler alert: there will be no answers to follow, as those will be the reader’s responsibility. Thus, the following questions are presented for readers to ponder on their own and hopefully come up with some “Why not?” ideas of their own. Consider the following: Why do we use only certain materials? Why do we need holes? Why do we use coverlayers? Why do we need lamination? Why do we need solder? Finally, for a little bit of controversy, why do we even need flexible circuits? Remember, there are no right or wrong answers; they are merely questions that might help us all to break loose from our mental chains (escape our prisons, if you will) and think in new directions and dimensions.
Having opened this brief discussion and challenge with a quote from one of the world’s greatest thinkers, it seemed appropriate to end with a quote from another great mind, Supreme Court Justice and philosopher Oliver Wendell Holmes, who astutely observed the following: “Man’s mind, stretched to a new idea, never goes back to its original dimension.” It seems doubly fitting knowing that the act of stretching also helps one to stay flexible in both mind and body.
Joe Fjelstad is founder and CEO of Verdant Electronics and an international authority and innovator in the field of electronic interconnection and packaging technologies, with more than 150 patents issued or pending.