IP Law Daily, PATENT—Fed. Cir.: Largan Precision’s imaging optical lens assembly patent survives Motorola’s invalidity challenges, (Sep 15, 2025)

By Saurabh Kashyap, B.A., LL.B., LL.M.

PTAB correctly found that a skilled artisan would not have been motivated to combine the cited prior art references.

In a non-precedential disposition, the U.S. Court of Appeals for the Federal Circuit affirmed the Patent Trial and Appeal Board’s (PTAB) decisions in an inter partes review (IPR) initiated by Motorola Mobility LLC that upheld multiple claims of an imaging optical lens assembly patent owned by Largan Precision Co., Ltd. The appellate court found that the Board’s findings on lack of motivation to combine two prior art references were supported by substantial evidence and that Motorola’s reliance on computer-aided modeling evidence did not demonstrate an independent reason to combine (Motorola Mobility LLC v. Largan Precision Co., Ltd., No. 24-1414 (Fed. Cir. Sept. 15, 2025)).

Background. The appellant, Motorola Mobility LLC, is a U.S.-based consumer electronics company best known for its smartphones and communication devices. The appellee, Largan Precision Co., Ltd., is a Taiwan-based manufacturer of optical lens modules widely used in smartphones.

The patent at issue, U.S. Patent No. 9,696,519 (the ’519 patent), is titled Imaging Optical Lens Assembly and covers a five-element lens system for imaging devices. Claim 1 recites specific structural features: a first lens element with negative refractive power and a concave surface, a sequence of alternating positive and negative refractive lens elements, and precise mathematical conditions for curvature radii and focal length ratios, including |R4/R3|<1.0, f5/f3<1.0, and −10.0<R1/f<0. These constraints are designed to achieve a balance between short track length, wide field of view, and improved image quality.

Motorola filed the IPR challenging all 27 claims of the '519 patent as obvious under § 103 based on Chung (U.S. Patent Application Publ'n No. 2015/0098137) in view of Sekine (U.S. Patent Application Publ'n No. 2013/0182339). Motorola argued that Chung disclosed all limitations except the R1/f ratio, which Sekine taught. According to Motorola, a skilled artisan would have combined these teachings to improve the field of view without compromising image quality. To support this theory, Motorola presented modeling results from ZEMAX, a widely used optical lens design software that allows engineers to simulate, optimize, and evaluate lens systems. Motorola argued that ZEMAX modeling confirmed a skilled artisan could achieve the claimed ratios when combining Chung with Sekine. The PTAB rejected Motorola’s challenge, finding no motivation to combine Chung and Sekine, and did not reach the issue of reasonable expectation of success. Motorola appealed.

Motivation to combine. The Federal Circuit upheld the PTAB's reasoning that a skilled artisan would have had reason to doubt the applicability of Sekine's teachings to Chung because of significant design differences. Chung disclosed embodiments with a negative first lens and a positive second lens, whereas Sekine had the opposite configuration. The Board also found that Sekine disclosed an inferior lens system with poorer image quality and a narrower field of view. The Federal Circuit held that these fact-based findings were supported by substantial evidence. Citing Adidas AG v. Nike, Inc., 963 F.3d 1355, 1359 (Fed. Cir. 2020), the court reiterated that obviousness requires a showing that a skilled artisan "would have been motivated to do so," not merely that a combination was possible.

Differences in prior art embodiments. The court agreed with the PTAB’s conclusion that Sekine’s teaching of shortening track length was inapplicable to Chung’s lens configurations because of differences in lens shapes and polarities. Motorola argued that the Board improperly considered polarity differences, which were raised only in Largan's preliminary response. The court rejected this contention, noting that Largan reasserted the point in its sur-reply and that Motorola had not sought to strike it. Thus, the Board acted within its discretion in considering these structural differences.

ZEMAX modeling evidence. Motorola argued that the Board erred by limiting its ZEMAX evidence to the “reasonable expectation of success” prong rather than considering it for motivation to combine. The Federal Circuit rejected this claim, finding that Motorola itself had characterized the ZEMAX modeling as confirming feasibility, not as providing an independent motivation. The court emphasized that computer optimization could produce nearly infinite combinations of lens parameters, but the mere possibility of optimization does not establish motivation. The court again relied on Adidas AG v. Nike, Inc. to stress that obviousness analysis turns on whether a skilled artisan would pursue the combination, not simply whether they could.

Substantial evidence standard. The court concluded that the PTAB’s findings rested on substantial evidence, including the inferior quality of Sekine’s lens system and the significant differences between Chung and Sekine. Motorola’s arguments essentially disputed factual determinations rather than identifying legal error. Under the deferential standard of review, the Board's findings were adequately supported.

Thus, the Federal Circuit affirmed the PTAB's decision, holding that Motorola failed to carry its burden to establish unpatentability of the '519 patent.

The Case is No. 24-1414.

Judge: Chen, R.

Attorneys: John D. Vandenberg (Klarquist Sparkman, LLP) for Motorola Mobility LLC. Kevin Russell (Russell & Woofter LLC) for Largan Precision Co., Ltd.

Companies: Motorola Mobility LLC; Largan Precision Co., Ltd.

Cases: Patent FedCirNews USPTO GCNNews