Luminescent materials and the use of such materials in anti-counterfeiting, inventory, photovoltaic, and other applications are described herein. The vehicle is an all-wheel drive vehicle, and the differential lock function produces an interaxle lock acting between the front axle and the rear axle of the all-wheel drive vehicle. Accommodation is achieved by relying upon the thickening and thinning of the optic as a result of the normal retracting and contracting of the ciliary body in response to the distance of an object from the viewer.