The Essence of Designing Around a Patent Is Not Creating a “Different Invention”
How companies can translate the legal boundaries of a patent into an actionable engineering design space
When a company identifies a competitor's patent, one of the most common reactions is:
“Our product looks completely different from theirs.”
In a more technically sophisticated organization, the reaction may instead be:
“Our invention is completely different from theirs as a whole.”
Both statements are dangerous starting points for a design-around analysis. The second can be particularly misleading. If a difference in product appearance creates a visual misconception, the belief that the “inventions are different as a whole” can be even more problematic because confidence in a new technical concept or superior performance may cause the team to skip the analysis that patent infringement actually requires.
Patent infringement does not ordinarily turn on how different two products or inventions appear when viewed as a whole. The first question is whether each limitation of the relevant claim, together with the relationships required among those limitations, is present in the accused product. A product may look entirely different and still raise an infringement issue if every required claim limitation is practiced. Conversely, even where two products perform similar core functions or create a similar overall impression, a substantially stronger noninfringement position may exist if a particular limitation is absent or if the claimed relationship or operating principle has been materially changed.
Suppose, for example, that an earlier patent claims the combination A+B+C, while our engineers develop a significantly improved system consisting of A+B+C+D+E. From an engineering perspective, the new system may appear to be an entirely different invention: it performs better, incorporates additional components, and may itself support patentable subject matter. But none of those facts necessarily eliminates the fact that A+B+C is still being practiced. Patentability and freedom to operate are separate questions. A later improvement may be independently patentable and nevertheless fall within the scope of an earlier, broader patent claim.
Accordingly, whenever someone in a design-around meeting says that “our invention is different as a whole,” the patent team should immediately return to a more disciplined question:
“Which limitation of each relevant independent claim is absent from our product?”
If the team cannot answer that question, the design-around analysis has not truly begun.
A Design-Around Is Not Merely a Product Modification. It Is a Corporate Risk-Management Process.
A patent design-around is the process of modifying a product's structure, component relationships, operating mechanism, or manufacturing process so that the company can deliver the function and value demanded by the market without practicing the competitor's claimed invention. The objective is not merely to build something that looks different from a competing product. More precisely, the objective is to identify the technical relationships that the patent legally protects and develop a commercially viable alternative outside those boundaries.
That is why an effective corporate design-around cannot be treated solely as a legal or engineering exercise. The team must determine which independent claims matter, which limitations may be eliminated or materially altered, whether the doctrine of equivalents remains a concern even after literal infringement is avoided, whether prosecution history estoppel or related prosecution statements narrow the patentee's available scope, and whether the prior art identifies alternative technical directions. At the same time, the company must evaluate whether the alternative can actually be manufactured at scale, whether its cost is acceptable, whether it preserves the performance customers value, and how it affects the launch schedule.
The best design-around therefore is not necessarily the design presenting the lowest conceivable legal risk. A design may be legally conservative yet commercially useless because it requires expensive new tooling or manufacturing processes. Conversely, management may rationally select an alternative that carries some residual patent risk if it can use existing production assets and preserve customer value. In practice, the optimum often lies at the intersection of legal risk, functionality, cost, manufacturability, and marketability.
For that reason, the patent team's work product should not be limited to a binary “infringement/noninfringement” conclusion. A stronger process develops multiple design alternatives and allows decision-makers to compare legal exposure, doctrine-of-equivalents risk, technical feasibility, manufacturing cost, market implications, launch timing, and residual uncertainty. The patent team's role is not to make the business decision for management. Its role is to structure the risk so that management can understand what the company gains, what it gives up, and what it remains exposed to.
More Dangerous Than Changing Appearance Is Assuming the Invention Is “Different as a Whole”
Organizations that are new to design-around work often focus heavily on changing color, size, shape, or the physical location of components. But if the patent claims do not require those visual characteristics, such differences may carry little or no significance in the infringement analysis.
Renaming a component is equally ineffective. If a patent claim refers to a “fastening screw,” calling the same structure a “fastening bolt” or “locking pin” in our drawings does not create a legal distinction. Patent infringement turns on the actual structure, function, and relationship of the component—not merely the label assigned to it. A nomenclature change is not a design-around.
Even greater caution is warranted when engineers themselves conclude that the new system constitutes an “entirely different invention.” As more features are added and a system becomes technically more sophisticated, the overall technological differences may indeed become substantial. Yet the patent question may continue to turn on something much narrower: whether the particular arrangement recited in the competitor's claim remains present.
The critical design-around question is therefore not “How much should we change?” but “What exactly should we change?”
In practice, changing the location or relationship of components may matter more than changing names or external appearance. A still stronger distinction may result from changing the path by which force, signals, or material are transmitted, or from changing the operating principle itself. Where technically feasible, the most robust alternative may be one in which the claimed element is no longer necessary at all.
Of course, there is no rule that “changing the operating principle always means noninfringement.” The ultimate conclusion remains dependent on claim construction and the particular facts. But the design question presented to R&D should generally move away from “What similar component can replace this component?” and toward “Can we solve the problem without needing this claimed arrangement at all?”
Designing the Product First and Asking the Patent Team to Justify Noninfringement Later Is the Most Expensive Form of Design-Around
In many companies, patent review still occurs near the end of the product-development process.
The company completes the design, builds prototypes, cuts tooling, orders components, prepares production plans, and only shortly before launch asks the patent team to review the product. The fundamental problem is that by the time the patent analysis begins, meaningful design changes have become commercially difficult.
If a problematic patent is identified at that point, the issue is no longer purely legal or technical. Tooling costs, certification expenses, advance component purchases, development schedules, and sales plans have already created substantial sunk costs. R&D and the business units may resist redesign by asking, “How are we supposed to change it now?” The patent team may then face pressure to find an argument that the already-completed product is noninfringing rather than to change the product itself.
At that point, design-around work can easily deteriorate into post-hoc rationalization.
More importantly, such a process may create an unfavorable factual record if litigation later arises. If a company knew of a competitor's patent and a substantial infringement concern, deliberately postponed meaningful review until redesign was practically impossible, conducted analysis principally to justify a predetermined conclusion, and continued selling without meaningful remedial action, those circumstances may make it more difficult to demonstrate that the company employed a reasonable, good-faith patent-risk management process. In the United States, the surrounding facts may become relevant to a willful-infringement analysis. Under Korean Patent Act Article 128(9), intentional infringement may also implicate enhanced damages of up to five times the determined amount of damages.
This point should not be oversimplified. Mere knowledge of a patent does not automatically establish willful infringement under U.S. law, nor should companies assume that obtaining a particular form of opinion letter is invariably required to avoid enhanced-damages exposure. The more important inquiry is what the company actually did after recognizing the patent risk: what it investigated, who participated in the analysis, what alternatives it considered, how it changed the product or otherwise managed the risk, and whether it consciously accepted a known risk without adequate response.
The preferred sequence therefore runs in the opposite direction:
The patent team should not operate merely as the final legal checkpoint that attaches legal arguments to a completed product. It should participate early enough to provide legally informed design constraints. That is why the first design-around discussion should occur during early development, when the company's legal design boundaries can still shape the engineering work.
A Design-Around Should Be Managed Through Four Different Meetings
Trying to complete a design-around project in a single meeting tends to blur roles. Patent counsel, R&D, manufacturing, marketing, and senior management are not responsible for answering the same questions. Separating the process into four stages makes it substantially clearer what must be prepared and who should make each decision.
The placement of the adversarial stress test is particularly important. It should occur before the legal boundary conditions are transmitted to R&D. If untested legal assumptions are converted into engineering requirements, the entire design effort that follows may rest on a defective premise.
Meeting 1. The Patent Team Defines the Legal Boundary First
The first meeting is not an ideation session. It is a legal preparation stage in which the patent team determines what must be changed.
The first step is to identify every relevant independent claim. Avoiding one independent claim does not mean that the entire patent has been designed around, and removing a limitation that appears only in a dependent claim does not eliminate potential infringement of its broader parent claim. Where multiple independent claims exist, each should be analyzed separately on the assumption that the patent may protect different aspects or axes of the technology. In appropriate circumstances, dependent claims may also require separate consideration, particularly where the noninfringement position depends not simply on the absence of an element but on limits imposed on the doctrine of equivalents, including limits associated with the prior art.
The claims should then be broken down limitation by limitation. Merely copying component names into a claim chart is not enough. The analysis should identify where each element is located, what it is connected to, what force, signal, or material it transmits, and what claimed relationships produce the recited function.
The prosecution history should then be reconstructed chronologically. What did the claims originally recite? Which prior-art references led to rejection? What arguments did the applicant make? Which limitations were added or narrowed? How did the issued claims ultimately distinguish the prior art? For design-around purposes, understanding why particular language entered the claim may be more useful than simply summarizing the issued claim text.
Prior art should not be viewed solely as potential invalidity material. Invalidity analysis and design-around analysis are separate exercises, but the prior art may reveal which portions of the technical landscape the patentee had to leave behind in order to secure allowance. If the patent obtained its current scope by distinguishing an earlier technical approach, a competitor may be able to explore a design that moves back toward that prior-art territory.
The final work product from Meeting 1 should not be a memorandum merely stating that “there is a risk of infringement.” It should identify legal boundary conditions and priorities for technical modification that R&D can actually use.
Meeting 2. Stress-Test the Legal Boundary from the Adversary's Perspective
The fact that the patent team has developed a legal-boundary analysis does not mean that the analysis has been adequately tested. The longer a team works with its own claim construction, the greater the risk of confirmation bias. A favorable construction may begin to feel self-evident; the prosecution history may be interpreted selectively; and the team may become overly confident that the prior art supports the preferred conclusion.
The purpose of the second meeting is to break that bias before the analysis reaches R&D. Once a faulty legal assumption becomes an engineering requirement, substantial engineering resources may be consumed before the weakness is discovered.
Meeting 2 should therefore be an intentional adversarial stress test. The patent team—or, where appropriate, outside counsel—should attack the Meeting 1 analysis from the patent owner's strongest plausible perspective.
“The element you classified as missing is substantively the same structure under a different name.”
“The allegedly different element was merely relocated, while the same claimed technical relationship remains.”
“Under the function-way-result test used in U.S. doctrine-of-equivalents analysis—or the applicable Korean equivalence framework—the accused feature could still be treated as equivalent.”
“The scope surrendered during prosecution is not as broad as your design-around theory assumes.”
“The prior art on which you rely is materially different from the structure now under review.”
Only after the strongest reasonably available attacks have been formulated should the company determine whether the proposed legal boundary remains defensible. The output of Meeting 2 is therefore a set of validated legal boundary conditions, with vulnerabilities either corrected or expressly identified. Only those validated conditions should move forward to Meeting 3.
Meeting 3. Translate the Validated Legal Boundary into Engineering Questions
R&D—and, where appropriate, manufacturing and marketing—joins the process in the third meeting. At this stage, the most important function of the patent team is not simply to explain the claims. It is to translate the validated claim analysis into questions that engineers can actually design against.
Telling engineers merely to “make something that does not infringe this patent” gives them little guidance about what needs to change. More useful questions might include:
- “Can we eliminate the internal support relationship within the housing?”
- “Can we replace the direct coupling with a different force-transmission path?”
- “Can we achieve the same function through linear motion rather than rotational motion?”
- “Can we design the system so that this particular fastening element is unnecessary?”
Patent counsel should define the relevant legal boundaries and risk factors, but should not attempt to monopolize judgments regarding engineering feasibility, performance, safety, or manufacturability. The preferable structure is iterative: R&D proposes multiple solutions outside the identified legal boundary, and the patent team evaluates each solution against the relevant claims.
Multiple design alternatives should be developed at this stage. A project that depends on only one design-around option can quickly run out of room if the legal assessment weakens, manufacturing cost proves excessive, or the alternative fails to meet customer requirements.
Design-around work is therefore less about finding one correct answer than about expanding the company's available design space.
Meeting 4. Convert the Patent Problem into a Management Decision
The fourth meeting compares technically viable alternatives from legal, engineering, and business perspectives. Because the underlying legal-boundary analysis was already subjected to adversarial testing in Meeting 2, the focus can now shift toward the relative defensibility and commercial practicality of each proposed design.
The first inquiry is whether each alternative avoids literal infringement of every relevant independent claim. If a defense depends on only one changed limitation, an adverse claim construction concerning that single limitation may collapse the entire position. Where feasible, it is generally preferable to create multiple absent or materially different limitations.
The team should next assess doctrine-of-equivalents risk. Is the difference merely one of terminology? Has a component simply been moved slightly? Or has the manner in which the function is achieved materially changed? The question should be tested from the perspective of a sophisticated adverse patent owner. The team should also determine how strongly the prosecution history and prior art support the proposed distinction.
The analysis then reaches questions that patent counsel cannot answer alone. Can the alternative actually be manufactured? Does it require new tooling? Will the part count increase? Will yield decline? Can the key performance characteristics valued by customers be maintained? How much will launch be delayed? What sunk costs in inventory and equipment will be affected?
At that point, the question changes from “Which design is safest?” to “Which design is best for the company?”
The patent team should not make that decision on management's behalf. It should explain which alternatives present stronger noninfringement positions, where each theory is vulnerable, and what residual patent risk remains. R&D should assess technical feasibility. Manufacturing should address production feasibility and cost. Marketing should define the minimum customer-value requirements. Senior management should then decide which risks the company is prepared to accept. This allocation of responsibility allows design-around work to function not as a legal prohibition mechanism, but as a corporate decision-making system.
A robust design-around rarely depends on a single distinction. Multiple missing or materially different limitations, separate defenses for separate independent claims, support from the prosecution history, support from the prior art, and meaningful differences in technical operating principle can combine to create a layered and substantially more resilient defense.
The Question “Can You Guarantee That It Does Not Infringe?” Requires a Different Kind of Answer
As a design-around project nears completion, a CEO or head of R&D will often ask:
“So can we now say that this product definitely does not infringe?”
That is rarely a question that should be answered with an unqualified “yes.”
First, claim construction carries uncertainty. Second, avoiding literal infringement does not necessarily eliminate the doctrine of equivalents. Third, other relevant patents may exist that were not included in the particular analysis. Designing around one patent is not the same thing as establishing complete freedom to operate for the product.
There is an additional practical consideration that is even more important.
There is no guarantee that the product ultimately manufactured and sold will remain identical to the product reviewed by the patent team, and the ultimate adjudication of infringement belongs to an independent decision-maker—not to the company itself. No matter how well-founded the company's noninfringement analysis may be, there is no assurance that a court in an actual dispute will adopt the same claim construction or legal assessment.
The patent team's report therefore should not end with the categorical statement, “This product does not infringe.” A more disciplined formulation would be:
“Based on the patents reviewed and the final design drawings presently provided, this design presents the most layered noninfringement position among the alternatives considered. This assessment, however, is based on the currently available record and our present legal and technical analysis, and it cannot guarantee that a court in an actual dispute would adopt the same claim construction or infringement determination. Any material change to the production or commercial product should be submitted for renewed review.”
The objective of a sound design-around analysis is not to manufacture a larger number expressing confidence. It is to make clear why the company reached its conclusion and which facts and assumptions that conclusion depends upon.
A Design-Around Does Not End at Design Freeze
Even an excellent design-around analysis becomes unreliable if the product reviewed by the patent team differs from the product ultimately sold.
After launch, procurement may adopt a substitute component to reduce cost. Manufacturing may make a minor structural modification to improve assembly. A supplier may use a different specification because of component shortages. An engineer may restore part of an earlier configuration to improve performance.
A seemingly minor modification may inadvertently reintroduce the very claim limitation that the design-around intentionally removed.
Design Freeze therefore is not merely a project-management milestone. It is also an important patent-risk control point. The CAD files, bill of materials, prototypes, and other specifications underlying the legal review should correspond to the actual production configuration. Material design changes should be subject to a change-control process that prevents implementation in production without appropriate patent-team review. When the post-launch product specification changes materially, the modified product should again be compared against all relevant independent claims.
Design-around work does not end on the day an opinion or internal memorandum is finalized. It is a lifecycle-management activity that continues for as long as the commercial product must preserve the design features on which the noninfringement position depends.
The Patent Team's Role Must Evolve from Risk Detection to Design-Space Creation
The easiest statement for a corporate patent team to make is, “This is risky. Do not do it.” But the business does not need the patent team merely to identify the existence of risk.
A more sophisticated patent organization should be able to say:
“The current configuration presents risk under this independent claim. If we eliminate this coupling relationship or materially change the operating principle, however, we can create a substantially stronger noninfringement position. The first approach may increase cost, while the second may affect performance, so R&D and manufacturing should develop multiple alternatives for comparison.”
The patent team is not the product designer. Engineers, in turn, are not responsible for construing patent claims.
The patent team defines legal boundaries and risk factors. R&D develops technical solutions outside those boundaries. Manufacturing evaluates scalability and cost. Marketing defines the minimum acceptable customer value and product specifications. Management weighs the remaining risk against the expected commercial benefit.
The patent team's role ultimately should expand beyond risk detection to encompass risk translation, risk structuring, and design-space creation.
In Design-Around Work, Prior Art Is More Than Material for Attacking a Patent
Prior art plays a distinctive role in design-around strategy.
In conventional patent practice, one of the most direct reasons to search prior art is to challenge novelty or nonobviousness. In design-around work, however, the prior art can also function as a map showing the company where the product may be moved.
Suppose a patent applicant distinguished prior-art configuration A by adding relationship B to the claim and arguing that the invention differed from A because of B. A competitor's only option is not necessarily to modify B slightly. In some circumstances, the stronger strategy may be to remove B altogether and move the design back toward the technical territory occupied by A or a neighboring prior-art approach.
This approach may provide value beyond avoiding the literal language of the claim. If the patent owner later attempts to expand the claim through the doctrine of equivalents far enough to capture the alternative design, the accused infringer may be able to argue that the asserted range of equivalents would improperly encompass the prior art. In U.S. patent law, this principle is commonly analyzed through the ensnarement doctrine, associated with cases including Wilson Sporting Goods Co. v. David Geoffrey & Associates in the Federal Circuit. Korean Supreme Court doctrine likewise recognizes limitations on the application of equivalents where the asserted scope would improperly extend into territory associated with the prior art.
A critical design-around question is therefore:
“What did this patent have to distinguish from the prior art in order to obtain its present scope?”
The next question is:
“Can we move our design back to the other side of that boundary?”
This is why reading only the words of the issued claims may not reveal the patent's most commercially useful boundary. The company should understand why particular language entered the claim in the first place and how that language emerged from the applicant's interaction with the prior art. A strong design-around converts that history into usable engineering design space.
Corporate Patent Counsel Can Help Change the Facts of a Future Dispute
Traditional legal education usually applies law to facts that have already occurred. The product already exists. The patent claims are fixed. The task is to compare the two and determine whether infringement has occurred.
Corporate design-around work is different.
The product can still be changed.
In other words, the company is presently creating the factual record that a court may one day be asked to evaluate.
For that reason, a corporate IP professional should not merely attempt to predict whether a court would find the present product infringing. The more valuable role is to intervene in the development process early enough to alter the structure of the future product in a direction that creates a more defensible factual record.
The process involves breaking the claim into limitations, using the prosecution history to identify legal boundaries, locating alternative technical space in the prior art, and translating those findings into engineering constraints. When engineers propose new structures, those alternatives are compared against the claims again, stress-tested from an adversarial perspective, and presented to management together with the remaining risks and costs.
In that process, the language of patent law becomes the language of engineering, and engineering alternatives are then translated into the language of management.
That is what it means to operate a design-around process effectively inside a company.
In the end, the objective of an effective design-around is neither to produce “a product that looks completely different from the competitor's product” nor to create “an invention that is completely different as a whole.”
The objective is to identify precisely the technical relationships legally protected by the competitor's patent, develop a commercially viable technical solution outside those relationships, and ensure that the company understands and manages the residual risk associated with that choice.
That is the essence of designing around a patent.
