In this dataset it means a patent family that combines PERC (passivated emitter rear contact) cell structure with a light-management claim — anti-reflection coatings, front or rear surface texturing, light trapping or broader photon management. The search combines PERC-related terms with light-management terms in the title and claims, restricted to the IPC classes covering rear passivation, surface treatment and photovoltaic conversion structures. It excludes PERC filings that make no light-management claim, and light-management filings for non-PERC cell architectures.

Citation counts in this dataset are led by a small set of Chinese-origin families alongside one US filing, all classified under the core semiconductor-device IPC group. High citation counts mostly reflect age and early filing date within the corpus rather than current commercial dominance, since older records simply have had more time to accumulate citations. A freedom-to-operate review should read these as influential precedent, then check current assignee activity separately.

Filing activity in this dataset rose from 6 records in 2017 to a peak of 14 in 2021, then declined toward a midpoint of 4 in 2022. That pattern is consistent with an architecture reaching a mature, well-defined claim space where the highest-value combinations of coating stack and texturing approach had already been filed by the early 2020s. Because publication lags filing by roughly 18 months, the very latest years understate true activity, but the downward turn from the 2021 peak predates that lag effect.

The IPC distribution shows all 65 records falling under the core semiconductor-device class, with only single-digit counts in adjacent classes covering coating deposition, crystal growth, corrosion treatment and electroplating. That imbalance suggests device-level architecture claims are well covered while the underlying process chemistry — multi-layer coating deposition sequences, texturing-etch parameters, rear-passivation deposition methods — carries comparatively few filings. Those process-level routes are the more promising areas to search before filing a new application.

Filing activity concentrates among a group of Chinese solar manufacturers and their regional subsidiaries, with the strongest co-assignee relationships appearing between different production sites of the same corporate group rather than between unrelated companies. China accounts for 53 of the 65 records via its receiving office, well ahead of the United States, PCT, Europe and India combined. None of the leading assignees show filings in the latest recorded year, though this is likely affected by publication lag rather than a genuine halt in R&D.