A light irradiation device that emits a light patch of uniform intensity. The device may be a dental light wand. The device has a light source, a lenslet array and an optional relay lens. The light source may be a laser or a collimated LED. Each lenslet of the lenslet array has two convex surfaces, a front convex surface, and a rear convex surface that is opposite to the front convex surface. The front convex surface has a focal point on the principal plane of the rear convex surface. The focal length of the front convex surface differs from the focal length of the rear convex surface. Light beams emitted by the light source pass through the lenslet array, and if a relay lens is present then pass through the relay lens, forming a light patch of uniform intensity.