Within this 91-record dataset, one supplier leads an 18-company ranking with 18 records, well ahead of the fifth-place holder at 7 and the tenth-place holder at 3. That leader and the other ranked assignees are predominantly glass and interlayer manufacturers rather than automakers or display electronics firms, which reflects where the underlying optical problem — controlling a wedge-shaped laminate's angle precisely enough to avoid ghost images — actually gets solved. The steep drop from first to fifth place suggests a concentrated core with a long tail of narrower filers below it.

A wedge interlayer is the plastic layer laminated between the two glass panes of a windshield, shaped so its thickness varies slightly across the HUD viewing region. That controlled wedge angle prevents the reflected HUD image from doubling into a 'ghost' image caused by reflections off both glass surfaces. Because the tolerance for the wedge angle is extremely tight and directly determines image quality, suppliers file dense claims around the exact angle profiles, rate-of-change limits and manufacturing tolerances — B32B, the layered-products class, covers 80.2% of the 91 records in this dataset for that reason.

Filing activity peaked at 22 records in 2021 and had fallen to 0 by 2024, a -100% swing over that span, which is the last three-year period this dataset can treat as complete. Counts for 2025 and 2026 appear low but should not be read as a real decline yet, because publication typically lags actual filing by roughly 18 months and those years are still filling in. The honest read is that the field ran hot through 2021 and cooled sharply afterward, but a firmer verdict on 2025-2026 needs another year or two of data.

The class composition points to it directly: B32B (laminates) and G02B (optics) together dominate the 91 records, while B60K, the class closest to vehicle and AR-HUD integration, covers only 22.0% of the same set. That gap suggests claims tying wedge-interlayer optics to sensor-fused calibration, dynamic eyebox control, or coating-interference correction are comparatively under-claimed relative to the interlayer chemistry itself. Anyone filing new claims in this field is more likely to find open ground on the integration and testing side than in the core laminate formulation.

US20230288699A1, assigned to Solutia Inc. and published 2023-09-14, claims a wedge-shaped interlayer with a poly(vinyl acetal) resin and plasticizer where the HUD region's wedge angle has an absolute rate-of-change below 3.0 prad/mm across the entire region, not just at a single point. That numeric, region-wide limit is a fairly specific and defensible claim scope — it does not block every wedge-interlayer approach, but it does narrow the room for competitors using the same resin chemistry and a similar rate-of-change basis. Alternatives using different measurement bases (e.g. spatial-frequency uniformity) or different polymer chemistries sit outside its literal scope, though a full freedom-to-operate check would need to confirm that against the full claim set.