Elementary, Mr. Watson: Flex Designs—The Future and Beyond

Electronics are continually evolving, driven by innovations in printed circuit board technology. Flexible PCBs have emerged as a revolutionary force, reshaping the PCB industry and influencing the design and functionality of countless electronic devices. Some believe that flexible PCBs are a relatively newer technology, but as we will see, that is not true. Since I’m an instructor, here’s a short history lesson on how we got here and what we can expect.

The genesis of flex PCBs can be traced back to the earliest days of the 20th century, a period marked by the advent of conventional rigid PCBs, when engineers and inventors were grappling with integrating copper conductors onto an insulated medium. In 1903, Albert Hanson received the first patent for a printed circuit board featuring thin conductive traces on a flexible insulating cloth material.

The following year, Thomas Edison experimented with chemical methods of plating conductors onto linen paper using cellulose gum and graphite. These inventions were truly ahead of their time and took several more decades to gain traction. Maybe not using today’s definitions, but fundamentally, the first PCB designs were flexible PCBs.

Many of the breakthroughs in flexbile PCBs lay dormant until the outbreak of World War II, when the military’s needs for smaller, more reliable components brought about a paradigm shift in the electronics industry. The era of miniaturization had begun. Flexible circuits, such as radar systems communication equipment, became indispensable in military applications. The lesser-known proximity fuze, among the first mass-produced printed circuit boards, was developed to trigger when in it came into close proximity to its intended target. This resulted in the military’s first guided missiles.

The quest for reliability, compactness, and durability drove the rapid adoption of flexible circuitry. In 1948, after the war, the U.S. released many of the first PCB patents to the commercial sector, and this resulted in a consumer electronics explosion in the mid-1950s.

The 1950s and ’60s brought about an intense space race competition between the United States and the Soviet Union. Space exploration demanded electronic systems that could perform flawlessly in the harshest conditions. The answer, again, was flexible PCBs, which emerged as pivotal components in space exploration. They found their way into applications for satellites, spacecraft, and space probes due to their ability to withstand radiation, extreme temperatures, and mechanical stress.

The reliability of flexible circuitry played a crucial role in the success of missions like the Apollo and the Voyager probes.

Over the following decades, a symbiotic relationship developed between consumer demands and the advancements in PCB design and manufacturing methods, especially the use of flexible PCBs.

I believe we’re now in a golden age of flex design, with several industries driving newfound interest and demand in the flex PCB industry. As consumers demand thinner and more compact devices, designers of flexible PCBs have created innovative and space-efficient designs, including smartphones, tablets, and wearables.

The automotive industry increasingly uses flex PCBs in various applications, such as infotainment systems, advanced driver-assistance systems (ADAS), instrument clusters, and sensors. Flex PCBs are well-suited for automotive applications due to their reliability and ability to withstand harsh environments.

But medical devices may be one of the biggest uses for flexible PCBs. These boards are crucial in medical devices and equipment, including medical imaging equipment (MRI and CT scanners), catheters, pacemakers, hearing aids, and wearable health monitors. They have the ability to conform to body shapes and compact spaces, and because of that, we see the most significant technological innovations in how flexible PCBs are used.

This increased interest in flexible PCBs shows no sign of slowing down. Some statistics project that the market will reach $15.29 billion by 2026, from $12.76 billion in 2020, at a CAGR of 3.1% during 20211.

So, what’s ahead for flexible PCBs?

  • Miniaturization: Design of flexible PCBs refers to the trend of making electronic circuits and devices smaller and more compact while maintaining or improving their functionality. I believe a substantial paradigm shift in the industry must require even smaller form factors, increased component density, and integrating multiple components and functions onto a single flex PCB. This reduces the need for separate boards, the integration saves space, and it simplifies assembly. On the positive side, we can expect miniaturized devices to be more energy-efficient, which is crucial for portable and battery-powered applications.
  • Bendable and foldable electronics: These represent a cutting-edge innovation in the world of flexible electronics. The technology aims to create electronic devices that can be physically bent, folded, or even rolled up, offering unique advantages in terms of portability, durability, and design flexibility. Some of the critical aspects of bendable and foldable electronics include:
  • Flexible substrates: The foundation of bendable and foldable electronics uses flexible substrates, typically made from materials like polyimide, liquid crystal polymer (LCP), or paper-based substrates—the original material used by Thomas Edison. These materials allow the electronic circuits to bend and flex without damage.
  • Foldable displays: These are one of the most prominent examples of this technology. They use flexible OLED (organic light-emitting diode) or AMOLED (active matrix of OLED) screens that can be folded like a book. These displays offer a larger real estate screen in a compact form, such as in foldable smartphones and tablets.
  • Wearables: Bendable and flexible electronics are ideal for wearables, including smartwatches, fitness trackers, and health monitoring devices. They can conform to the body, providing comfort and improved wearability.
  • Stretchable circuits: There is ongoing research into stretchable conductive materials and substrates, which will lead to flexible PCBs that can stretch and conform to irregular shapes. This opens new possibilities in wearables, health monitoring, and soft robotics.

The foundation of stretchable circuits uses elastic substrates, often made from silicone, rubber, or other elastomeric materials that provide the necessary mechanical flexibility. This new technology will open new applications in healthcare, such as wearable biosensors, electronic skin, and health monitoring patches. They enable continuous and comfortable patient monitoring, and there is research into stretchable circuits that can be seamlessly integrated with biological tissues, potentially allowing for advanced prosthetics and human-machine interfaces.

Stretchable circuits have the potential to transform industries like healthcare, robotics, and wearables by offering a new level of flexibility and adaptability. Research in this field continues to push the boundaries of what is possible with flexible and stretchable electronics, creating opportunities for innovative and practical applications.

Everyone, it seems, is jumping on the flexible PCB bandwagon. As PCB designers, it's not a matter of whether you will design a flexible PCB but when. Now is the time to prepare for these industry changes.

Class dismissed.


1. "The Global Printed Circuit Board Market: Key Insights, Forecasts, and & Growth Outlook," MKTPCB.com.

John Watson, CID, is a customer success manager at Altium.



Elementary, Mr. Watson: Flex Designs—The Future and Beyond


Electronics are continually evolving, driven by innovations in printed circuit board technology. Flexible PCBs have emerged as a revolutionary force, reshaping the PCB industry and influencing the design and functionality of countless electronic devices. Some believe that flexible PCBs are a relatively newer technology, but as we will see, that is not true. Since I’m an instructor, here’s a short history lesson on how we got here and what we can expect.

View Story

Elementary, Mr. Watson: Circuit Simulation, SPICE, and AI


According to the Federal Aviation Administration’s flight time limitations and rest requirements, a commercial pilot is restricted to 36 flight hours in a week, 100 hours in 28 days, and 1,000 hours in any calendar year. But before these pilots even start flying the friendly skies, they spend considerable time in a flight simulator. In the same way, PCB design and circuit simulations provide the same advantages: a controlled, safe environment for testing a circuit without the considerable overhead of fabricating and assembling the PCB.

View Story

Elementary, Mr. Watson: Honey, I Shrunk the PCBs


As an industry, we live in our own version of “Honey, I Shrunk the Kids.” PCB designs are shrinking smaller and smaller with each design spin. Our industry demands the latest and greatest, where innovations coming off the line must be smaller and sleeker and have all the latest new functions, which, as we know, determines the fit and form. Miniaturization and integration are growing trends with electronics.

View Story

Elementary, Mr. Watson: Where Have All the PCB Designers Gone?


What are the biggest challenges in PCB design? Now, that’s a loaded question, but one that I’d like to talk about. Before I do so, I think it’s helpful to talk about challenges themselves, how we view them, how they affect us, and what we do about them. What one person perceives as a challenge may not be a challenge for another person. Challenges can vary based on individual circumstances, goals, values, and strengths or weaknesses. Some folks avoid challenges or never expect to have issues, but this is entirely unrealistic.

View Story

Elementary, Mr. Watson: Slash Sheets a ‘Smorgasbord’ of Materials


Slash sheets touch on materials, one of my favorite areas of PCB design, and what I refer to as “the buffet of the PCB world.” After all, this smorgasbord of materials comes in an endless variety, with differing balances of reinforcement and resin, from different manufacturers and vendors, and from a variety of sources. Add the possibility of out-of-date or deteriorated panels, and it makes ensuring the quality of your next PCB design a real hit or miss.

View Story

Elementary, Mr. Watson: Responsible PCB Design Must Go Beyond RoHS


In the field of PCB design, a massive paradox exists. No doubt, the PCB industry is a fascinating field. The ever-changing design environment faces constant and more complex challenges to make products smaller, faster, and cheaper. There are endless ways that electronic innovation changes lives for the better, as seen when advanced medical systems provide patients a new lease on life. But there also is a downside, an unfortunate side, to PCB design, and it has bothered me for some time. There is a massive amount of new PCB products hitting the market, especially in the consumer marketplace. But what happens to the "obsolete" products that are discarded, known as e-waste? This dark side of the PCB industry is not spoken about in social circles, but with innovation comes some negative.

View Story

Elementary, Mr. Watson: If Not You, Then Who?


I have had the opportunity to do a considerable amount of traveling. Over many visits to the Philippines, I noticed a distinct lack of nursing homes, and learned that it is a common practice for children to take care of their parents. They even have a designated term for this practice, ma alaga, roughly translated as "take care of." This practice leads to some fantastic outcomes in the culture, resulting in each age group taking care of its own, with a beautiful overlapping of different generations. What a great concept.

View Story

Elementary, Mr. Watson: Turning Your Career up to Eleven


In the 1984 classic rock documentary “This Is Spinal Tap,” guitarist Nigel Tufnel proudly demonstrates an amplifier whose volume knobs are marked from zero to 11 instead of the typical zero to 10. From that movie, we get the phrase, “Turn it up to 11.” It’s a lesson of seeing a limit and exceeding it. So, here’s a rather personal question: What is your level 11? You are the only person who can answer that question, and I hope you will, both in your personal life and in your career.

View Story

Elementary, Mr. Watson: Advanced Packaging Not a Passing Fad


As it is said, necessity is the mother of invention. That is precisely the situation when we are discussing the PCB design industry. We are living in what can only be described as the golden age of Electronics. The advancements and innovations are growing by leaps and bounds. Never in history has the field of electronics grown at such a fantastic rate. The advance integration packages field is one of the fastest-growing and most exciting.

View Story

Elementary, Mr. Watson: Designing For a Higher Purpose


John Watson asks the question to PCB designers: Why do you do what you do? It's a question someone asked him recently and the answer was clear. In this column, John shares a personal journey of a friend whose life was changed in an instant because of the efforts of so many, including a PCB designer. This story should give us all pause to consider the magnitude of what we do. The "puzzle pieces" of a PCB design become a working model for consumer products that affect even our most basic senses. Read on to learn more about the "why" behind his passion for PCB design.

View Story


Elementary, Mr. Watson: The Art of the PCB


After finishing the statue of David, Michelangelo—Italian sculptor, painter, architect, and poet of the High Renaissance—was asked how he had created such a beautiful work of art. He said, “The sculpture was already complete within the marble block before I started my work. I merely had to chisel away the superfluous material.” After decades of being in the industry and seeing countless designs, it’s still amazing to me to see the exceptional beauty of a well-done PCB design. For designers, each PCB begins as a blank canvas; not knowing what the final product will look like, we walk a fine line between engineering and artistry, often producing fascinating results.

View Story

Elementary, Mr. Watson: Is Your Bathroom in the Kitchen?


Several years ago, a report came out of St. Louis of a strange apartment on the market. It was in the community of Central West End. With a small floor plan of only 200 square feet, the entire bathroom was placed right in the middle of the kitchen. Well, that's interesting. It gives new meaning to the studio apartment. Well, with closer examination, there are several convenient features available, so here's my point: In this story lies some fantastic lessons for us as PCB designers. In real estate, it's pretty uncommon to find the bathroom in the kitchen; but metaphorically speaking, it's done all the time in a PCB design (ouch).

View Story

Elementary, Mr. Watson: Is the Tail Wagging the Dog?


I recently had the opportunity to work on a rather critical PCB design project during what should have been the final design review. Unfortunately, after presenting my well-organized PowerPoint presentation, I asked the most challenging question to the group of assembled engineers and managers, “So, what do you think?” As we went around the room, nearly every comment started with something like, "You know what we could do..." Ideas flew around the room, fueling a full-blown brainstorm. Unfortunately, what followed could best be described as organized chaos. The result was that several of the suggestions took the product back to re-design, and what was supposed to be the final steps didn't happen.

View Story

Elementary, Mr. Watson: Anatomy of Your Component—Footprint, Part 2


Have you ever gone to a buffet hungry and looking forward to digging in? You grab the plate and start down the food line, picking things as you go. Halfway through, your plate is stacked up with food, looking very similar to the Leaning Tower of Pisa. Then you get to the good stuff at the end of the buffet, but there’s no room on your plate. At this point, you probably feel much like that with the first part of looking at our footprint, but rest assured, although your plate is already full, the good stuff is still waiting for us. I have saved the best for our second offering.

View Story

Elementary, Mr. Watson: The Anatomy of Your Component—Footprint


I hate to disappoint you if you expect to get everything about footprints from this modest column, but a short search online results in a long list of technical standards and books on this subject. So, I will only hit the surface of the discussion. I have often spoken about the parent-child relationship principle in PCB design. In this series, we have learned that we can see how that "relationship" is supported directly by the information in the component itself. As a short review, the parent-child relationship is where you use an input of data, material, or parts (parents) as the foundation or resource for another item or document (child).

View Story

Elementary, Mr. Watson: The Anatomy of Your PCB Component, Part 2


In the start of my series of the anatomy of a component, I discussed that the component has two major divisions. The first is information that consists of name, description, parametric information, sourcing (part choices), and the datasheet (Figure 1). Next, the component comprises symbol, PCB footprint, 3D model, and simulation models. I gave the example of the dissection of the frog, with an analogy that every part has a purpose. In the same way, each part of our component has a distinct purpose in our PCB design, including our models.

View Story

Elementary, Mr. Watson: The Anatomy of Your PCB Component, Part 1


One of the classes I dreaded the most in school each year was biology. This was because I knew it was only a matter of time before I would face the rite of passage for most high school students: dissecting a frog. It wasn’t something I ever looked forward to. We had to go through the same educational exercise and maybe with the same apprehension for most of us. But my point in bringing up the painful experiences of our high school years is, although it was difficult, I did learn a powerful lesson: Every part has a purpose.

View Story

Elementary, Mr. Watson: The Five Pillars of Your Library, Part 5—Traceability


We have reached the end of this series regarding the five pillars of the component library. We now have a robust library that provides the required resources for the ever-changing industry. Above that is having a flexible library to grow with the company. The final pillar is traceability. Why is traceability so essential and considered a pillar of our library? Read on for details.

View Story

Elementary, Mr. Watson: The Five Pillars of your Library, Part 4—Review


I trust that you have been enjoying this series on the five pillars of your library. Now that we have a single library managed using our revisioning, and we have lifecycle schemes organized so that we can easily find something in the component category, family, and subfamilies, we are now ready to look at one of our library's most vital principles and pillars: reviewable.

View Story

Elementary, Mr. Watson: The Five Pillars of Your Library, Part 3—Architecture


Before I continue with the series of the five pillars of your library, I want to do a little review. Although every library is different, the five pillars are consistent with any sound library. You place these pillars to support a specific building section in building construction. To pull one out requires the remaining ones to hold the total weight above. So, each of these supports is needed for your library to succeed. You cannot choose which of them you intend to follow; to pull just one out results in the toppling of the others.

View Story


Elementary, Mr. Watson: PCB Data Management and Security


As a grandfather of six grandchildren, one of my great joys is spending time with them. There is nothing better than spending an afternoon at the park and especially playing on the teeter-totter. It's all fun and games until grandpa gets on one side, and they try to lift me. Then the harsh reality and a teachable moment in leverage, balance, and just how heavy grandpa really is hits pretty hard.

View Story

Elementary, Mr. Watson: We’ve Never Done It That Way Before


The September edition of Design007 Magazine discussed the theme of collaborating and working with a team. In that issue, I wrote a feature article called “PCB Design Is a Team Sport.” After that edition was published, I had several follow-up questions and conversations with individuals; they agreed on the importance of teamwork but felt that it's easier said than done. It's challenging because of the inherent problem of team members accepting or handling change very well. Change it's a word that sends shivers down the spine of some. You know those sort of individuals. They're easy to identify. The ones that constantly remind everyone, "We never did it that way before." As if how we did things in the past was so much better.

View Story

Elementary, Mr. Watson: First, Component Shortages, and Now Hot Dogs?


When I considered the title for this month’s article, I seriously considered calling it "From the Frying Pan Into the Fire" because I’m sure you’ve noticed recently that the component shortage problem has only worsened—we’re now seeing other supply lines breaking down.

View Story

Elementary Mr. Watson: PCB Design—It's a Team Sport


One of the hard lessons of this past year was about the value of the team and collaboration. I have repeatedly heard how many of us have a newfound respect and appreciation for the teams we work with inside our companies. Out of necessity, we had to find new ways to collaborate.

View Story

Elementary, Mr. Watson: The Danger of Rogue Libraries


For PCB designers, the most common part of the library is the collection of components used in the PCB design process. But, I have seen some libraries have other information, including a resource area, a group of documents, standards, and articles. So basically it can have anything you want.

View Story

Elementary, Mr. Watson: Epic Fails with Design Rules


Various sciences, including physics, mathematics, chemistry, are significantly involved throughout the PCB design process, rules that can sometimes be bent but not broken. However, the rules that designers break and ignore altogether and very often are the design rules.

View Story

Elementary, Mr. Watson: Managing Risk in PCB Design


PCB design is like bungee jumping. With the complexity of a PCB design, the intricate details, and various steps, it's rather easy to make mistakes. Those mistakes, many times, do not show up until it's too late and the board has gone off to fabrication and assembly. By the way, a good rule is not to use your assembly house as your quality control team for PCB designs.

View Story

Elementary, Mr. Watson: Time to Market, from Ludicrous Speed to Plaid


Mel Brooks may have something to teach us about going "ludicrous speed" in getting our designs to the finish line. John Watson explains.

View Story

Elementary, Mr. Watson: Trust but Verify


Over many years, I have seen some elaborate PCB library systems. However, the best ones were those not based on the size but rather the quality of the information. That old axiom is definitely “not quantity but rather quality.”

View Story

Elementary, Mr. Watson: Paying the Price To Be a PCB Designer


Today, the electronics industry is flourishing with innovations and technologies. The result is that the “good” designers are left in the dust. Truthfully, our industry doesn't need more good designers; rather, we need great designers—those who can face any challenge and instead of cowering in the corner, looks at the task at hand and says, "Bring it on."

View Story


Elementary, Mr. Watson: Demystifying Bypass Capacitors


As PCB designers, we work under the simple rule of cause and effect, and a PCB design can quickly become a petri dish for the butterfly effect to flourish. One of those areas that can quickly snowball into major problems is your PCB power distribution structure. When it goes wrong, it usually goes very wrong and has significant issues throughout your design.

View Story

Elementary, Mr. Watson: Density Feasibility Putting 10 Lbs in a 5-Lb Bag


Whether on a customer, a system, or a PCB level, it’s essential to understand the final objective and how you intend to get there and meet the customer need at the forefront of any project. In this column, John Watson addresses density feasibility and more.

View Story

Elementary, Mr. Watson: Location, Location, Location


When it comes to PCB design, one of the most overlooked principles is component placement. Similar to a home, the component location has a considerable impact on the quality and is the real value of a PCB design. John Watson examines five rules to follow when it comes to component placement.

View Story

Elementary, Mr. Watson: Overcoming PCB Designs Pitfalls


When starting every PCB design, the hope is that we can navigate through any pitfalls that arrive. Unfortunately, many times, issues happen that you do not handle correctly; they fall through the cracks and end up in your PCB design. John Watson explains how that is when the real problems begin.

View Story

Elementary, Mr. Watson: How to Ruin Your PCB Design in 4 Easy Steps


John Watson has seen firsthand how quickly PCB designs can “go off the rails” by not following a few simple principles. In this column, he looks at four practices that can easily ruin your PCB design.

View Story

Elementary, Mr. Watson: PCB Components Naming Conventions


How you accurately analyze and identify certain information has a direct connection to the overall success of your PCB designs. In this column, John Watson focuses on the conventional naming scheme for the schematic symbol and footprint to prevent headaches and ulcers later.

View Story

Elementary, Mr. Watson: Collaboration in the PCB Design Process


The past few months have been trying for everyone, with many of us working from home. However, there are still the underlining principles of collaboration to step into a role to finish the necessary tasks to keep a project moving forward. John Watson, CID, explains.

View Story

Elementary, Mr. Watson: Reinventing Yourself


When COVID-19 first hit, many businesses were forced to close, and we immediately saw its impact on the service industry. Whatever challenge you’re facing, John Watson emphasizes that it’s time to hit the switch on reinventing.

View Story

Elementary, Mr. Watson: The Positive Side of COVID-19


With the recent COVID-19 outbreak worldwide, most of us have been forced to reshuffle how we work, live, and play. Something like this has never happened before in our lifetimes, and it is scary and challenging, but difficult times develop resilient people. John Watson shares some of the positive things he has already noticed come out of this situation.

View Story

Elementary, Mr. Watson: Are We There Yet?


Anyone who has taken a road trip with children knows the question, “Are we there yet?” very well. This question also applies to PCB design. If you are not careful, your PCB project could easily go off track and you could lose sight of what you are doing (objective), why (motivation), how (process), and when (schedule). John Watson emphasizes the importance of these fundamental questions.

View Story
Copyright © 2023 I-Connect007 | IPC Publishing Group Inc. All rights reserved.