activematrix

Active matrix is a addressing scheme used in flat-panel displays in which each pixel is paired with an active switching element, typically a thin-film transistor (TFT), to control and hold its state. This contrasts with passive-matrix addressing, where pixels are driven directly by row and column lines without a dedicated storage element.

In an active-matrix LCD, each pixel has a transistor and a storage capacitor. Gate lines select a row, data lines apply the pixel voltage. The transistor charges the capacitor to the desired voltage and then, when deselected, the capacitor holds the voltage between refresh cycles. This enables higher resolution, higher contrast, and faster response times.

Common implementations use amorphous-silicon (a-Si) TFTs, with advances in polycrystalline silicon (poly-Si) and oxide materials such as IGZO providing higher mobility. Active-matrix displays enable precise control of color and grayscale, and the same principle is used for OLED-based panels where each pixel is driven by a transistor.

History and impact: Active-matrix addressing became widespread with the mass adoption of TFT LCDs in the late 1990s and 2000s, powering laptops, desktop monitors, smartphones, and televisions. While more complex and costly to manufacture than passive-matrix designs, they deliver significantly better image quality, larger sizes, and higher resolutions.

In modern terminology, "active matrix" describes any display in which per-pixel switching elements actively drive and retain the state of each pixel, as opposed to passive-matrix approaches.