Using Shape Memory Alloy (SMA) actuators for focus compensation in XR displays

Using actuators to correct focus has been shown as the preferred method in many optical systems including cameras. In XR displays focus adjustment is also required. It can prevent a loss of performance when ambient temperature changes causing distortion of the optical elements and can also enable dynamic adjustment of the virtual image distance. Existing actuators require always-on power consumption and are large and heavy, all of which is undesirable. Here we will present a novel SMA actuator which utilizes the unique characteristics of SMA to provide focus compensation without compromising power consumption in a lightweight and compact form factor.