In this dataset, the two terms describe the same underlying problem from slightly different angles: light generated inside the OLED stack is trapped by internal reflection at layer interfaces, and both light-extraction and outcoupling-enhancement claims describe structures — microlens arrays, scattering layers, textured substrates — designed to let more of that light escape. Patent drafters use the two terms somewhat interchangeably, which is why the search string here treats them as equivalent claim language. Practically, if you are running a prior-art search, you need to search both terms plus microlens array explicitly, since some filings use only one of the three.

The dataset shows filing activity concentrated among a small group that includes materials suppliers such as Corning and SABIC, OLED specialist Universal Display, device makers, and at least one university research group. No single assignee dominates by volume, and the co-assignee pairings (for example Corning with Samsung Corning Precision Materials) suggest some of this activity happens through joint materials-development filings rather than a single company's internal R&D. None of the tracked assignees show filing activity in the most recent year, so today's leaders reflect who claimed early rather than who is currently most active.

The filing trend in this dataset rose to a peak of 7 filings in 2017 before falling to zero by the 2022 midpoint. That pattern is typical of a technology area where the foundational structural fixes — extraction layers, microlens sheets, barrier-and-electrode substrate combinations — get claimed in a short window once the underlying device architecture stabilizes, after which there is less unclaimed structural space left to file around. It does not necessarily mean OLED lighting itself has stalled; it means this particular optical-design claim space has been largely staked out. Note also that the most recent one to two years in any patent trend are understated because publication lags filing by roughly 18 months.

US20180076399A1, filed by SABIC Global Technologies B.V. and published in March 2018, claims a multifunctional flexible substrate that combines a barrier layer, a transparent electrode layer and a microlens array layer containing particles into a single sheet for use in an OLED element. It blocks designs that combine all three of those layers into one integrated sheet in a way that reads on the claim language, but it does not block extraction approaches that use a microlens array without a barrier layer in the same sheet, or that use a different extraction mechanism such as a distributed Bragg reflector. Anyone designing a new substrate should compare their layer stack against the specific claim elements rather than assuming any microlens-containing substrate is covered.

Based on IPC composition, the core organic-semiconductor and general-semiconductor-device classes (H10K and H01L) are saturated relative to the materials-side classes: coatings, polymer compositions, polymer additives and glass compositions each appear in only a handful of the 33 tracked records. That imbalance suggests device-structure claims are dense while materials-formulation claims — specific coating chemistries, polymer additive systems, and glass-composition extraction substrates — are comparatively open. A first claim in that space would likely center on a specific material formulation applied to a known extraction structure, rather than a new structural architecture.