Stepwise‑controllable dimming blind enabled by intermediate‑region‑engineered patterned polarizers

Abstract Seamless, power‑free dimming elements are desirable for architectural and automotive use. However, slide‑type blinds based on conventional polarizers rely on cut‑and‑laminate assembly, making the incorporation of oblique polarization axes practically difficult and resulting in effect in ON/OFF‑like two‑level control. We propose a stepwise‑controllable blind composed of two patterned polarizer sheets that introduce intermediate regions between main polarization‑axis domains. By pattern design, oblique axes can be placed arbitrarily, enabling multi‑level brightness control via 2 mm sliding steps governed by Malus’ law. Moreover, boundaries are bridged by five 10 μm sub‑regions with 5° axis increments, which smooth optical discontinuities, suppress oblique‑incidence leakage, and reduce perceived in‑plane color/luminance banding. The polarizers employ a nano-triangular wave-shaped polarizer that forms multiple in‑plane axes in a single process without oblique deposition, providing broadband (VIS–IR) functionality. Scanning electron microscopy confirms uniform triangular‑wave replication with a pitch of ≈ 140 nm and structural continuity from main to intermediate regions. Spectral transmittance exhibits a thickness‑tunable dimming envelope (e.g., at 550 nm, 4.4–31.6% for 40 nm Al vs. 1.1–22.8% for 50 nm). Microspectroscopic reflectance shows smooth, non‑abrupt transitions across boundaries. Polarization ray‑tracing at 5° oblique incidence indicates ≈ 8× suppression of boundary‑originated leakage at g = 100 μm, with mitigation retained up to 300 μm. These results demonstrate that pattern‑engineered oblique axes and intermediate‑region design together enable passive, power‑free multi‑level dimming while improving appearance uniformity and blocking performance.