Can visual similarity between references still provide a motivation to combine after LKQ v. GM?
Short answer: Yes. Visual similarity between references can still supply a motivation to combine after LKQ, but it is no longer a rigid threshold requirement, and it is one factor within the flexible Graham/KSR analysis rather than a controlling test.
Start with the controlling authority. In the en banc decision, the Federal Circuit overruled the Rosen-Durling framework, including the requirement “that any secondary references be ‘so related’ to the primary reference that features in one would suggest application of those features to the other” as “improperly rigid” 29756600. The court cautioned that a secondary reference need not, on its own, generate the motivation to combine: the statute “gives no indication that a secondary prior art reference need be ‘so related’ to the primary that—as the Durling test is too readily understood to demand—it creates its own motivation to combine the two prior art references” CAFC-20240521-Lkq-Corporation-v-Gm-Global-Technology-Operations-LLC-21-2348.
That said, LKQ preserves visual similarity as legally relevant. The Federal Circuit expressly tied the degree of visual similarity to the motivation-to-combine burden: “the more different the overall appearances of the primary reference versus the secondary reference(s), the more work a patent challenger will likely need to do to establish a motivation to alter the primary prior art design in light of the secondary one” CAFC-20240521-Lkq-Corporation-v-Gm-Global-Technology-Operations-LLC-21-2348. The logical converse—that greater visual similarity lessens the work required—means similarity still helps carry the motivation showing, just as a matter of degree rather than a gate.
The USPTO’s implementing guidance (examiner guidance, not binding law) confirms this reading. It instructs that the flexible approach “does not use a threshold ‘similarity’ requirement” and that “the motivation to combine these references need not come from the references themselves” REF-20240522-USPTO-Memo-LKQ-Obviousness-Guidance, REF-20240522-USPTO-Memo-LKQ-Obviousness-Guidance. So visual similarity is not required to establish motivation, but it is not forbidden as a source of it either.
On the specific proposition in your question—that similarity itself can supply motivation—a district court has said so directly. In the remand proceedings in the same case, a district court in the N.D. Ill. concluded that “the mere similarity in appearance” between primary and secondary references “itself provides the suggestion that one should apply certain features to another design” and can demonstrate a motivation to combine DCT-2025-06-30_ilnd_121-cv-05854_doc353_LKQ_Corporation_v_General_Motors_Compan. Treat this as persuasive authority only—it is a district court opinion, not binding on any court, and it does not decide the underlying evidentiary question, expressly noting “[t]he Court does not decide this issue at this time” DCT-2025-06-30_ilnd_121-cv-05854_doc353_LKQ_Corporation_v_General_Motors_Compan. It also rested on the fact that GM did not contest that the references (all front vehicle fenders) were related enough to establish motivation DCT-2025-06-30_ilnd_121-cv-05854_doc353_LKQ_Corporation_v_General_Motors_Compan.
Two practical caveats grounded in the sources. First, whatever the motivation’s source, the combination must still yield the same overall visual appearance and rest on “some record-supported reason (without hindsight)” that an ordinary designer would have made the modification 2024-002635. Second, both references must be analogous art, and a bare assertion of visual similarity is not a substitute for that showing—as one prosecution response argued, an examiner must explain “why Buffini is analogous (and not just allegedly similar)” to the claimed design 29787268.
Bottom line: After LKQ, visual similarity between references remains a legitimate and relevant consideration that can contribute to—or even, per one non-binding district court, supply—a motivation to combine, but it functions within the flexible Graham/KSR framework rather than as the mandatory “so related” threshold the Federal Circuit overruled.
A note from me after review: the answer above holds up on the law, with two refinements worth making explicit. First, the requirement that both references be analogous art comes from the en banc LKQ opinion itself. It is a holding, not merely a point of examiner guidance, and it is the strongest authority for that caveat. Second, the “logical converse” observation, that greater similarity lessens the challenger’s work, is a fair inference from LKQ’s language, but it is not the court’s express rule; comparative similarity bears on the amount of proof required, it does not automatically supply the motivation. Neither point changes the bottom line: after LKQ, visual similarity remains relevant evidence on motivation to combine, within the flexible Graham framework, and the challenger still needs a record-supported, non-hindsight rationale.
### Source Documents:
– CAFC-20240521-Lkq-Corporation-v-Gm-Global-Technology-Operations-LLC-21-2348
– DCT-2025-06-30_ilnd_121-cv-05854_doc353_LKQ_Corporation_v_General_Motors_Compan
– REF-20240522-USPTO-Memo-LKQ-Obviousness-Guidance
– 29756600
– 2024-002635
– 29787268
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