CVD diamond films are claimed around achieving a genuine crystalline diamond lattice with high sp3 carbon content, typically requiring high-temperature chemical vapor deposition and substrate preparation steps. DLC coatings are amorphous carbon films that mix sp3 and sp2 bonding and can be deposited at lower temperatures, trading some hardness and thermal conductivity for easier processing and broader substrate compatibility. In this dataset both are captured together because claims frequently overlap on deposition method, adhesion and friction-coefficient limitations rather than crystal structure alone. Anyone drafting new claims should be precise about which structure is intended, since examiners in this art treat sp3 content thresholds as a key distinguishing feature.

The filing trend in this dataset runs from 47 filings in 2017 down to a partial 3 in 2026, with the 2022 midpoint at 26 — a clear downward trajectory rather than a plateau. This can reflect several things at once: the core CVD deposition methods reaching a mature, well-claimed state; some assignees shifting to trade-secret protection for process parameters that are hard to reverse-engineer from a granted patent; and ordinary publication lag understating the last one to two years of activity. It does not necessarily mean commercial interest in diamond and DLC films has declined, only that new patent claims in this specific method space have slowed.

The dataset shows filing concentrated among a mix of industrial gas, cutting-tool and electronics-materials companies, several of which show no filings in the most recent year captured here. Co-assignment is rare — only ten co-assignee pairs appear across the full set — so most patents are held by a single company rather than jointly. Before treating any one company as dominant, check whether recent-year silence reflects a genuine pull-back or simply publication lag on filings not yet public.

US4707384A is the most-cited record in this dataset, with 379 citations, covering a composite body coated with one or more layers of inorganic materials including CVD diamond. Its high citation count marks it as foundational blocking art that later filings in composite diamond-coated bodies routinely had to design around or license. Any new filing targeting multi-layer diamond coatings on a substrate body should review this patent's claim scope directly rather than relying on citation count alone, since an expired foundational patent can still define the boundaries competitors built their own claims against.

IPC composition in this dataset is heavily weighted toward C23C coating and C30B crystal-growth codes, which together account for the bulk of records, while device-integration classes like H01L semiconductor devices and H01J electron tubes are comparatively thin. That imbalance suggests branches such as sp3-content gradient control at layer interfaces, adhesion interlayers for non-carbide substrates, and low-temperature growth optimization remain less crowded than core deposition-method claims. A first claim in one of these branches would need to specify the interface or temperature parameter precisely, since generic coating-method language is likely to run into the dense prior art already covering C23C.