A projecting device includes a light source, a filtering component, a reflecting mirror, a digital micro-mirror device, a projecting lens, and a panel. The filtering component changes lights emitted from the light source into substantially parallel polarized ultraviolet lights. The reflecting mirror reflects the substantially parallel polarized ultraviolet lights to the digital micro-mirror device. The digital micro-mirror device includes microscopic mirrors arranged in a rectangular array configured to be adjustable to reflect the substantially parallel polarized ultraviolet lights reflected by the reflecting mirror to the projecting lens. The projecting lens diverges the substantially parallel polarized ultraviolet lights. The panel includes a transparent substrate, a first fluorescence material layer, a second fluorescence material layer, and a third fluorescence material layer. The first, second, and third fluorescence material layers are positioned on the transparent substrate and emit red, blue and green lights when excited.