A display assembly includes a convex lens, a light-absorbing layer, and a refractive index-adjustable layer disposed therebetween. The refractive index-adjustable layer has a refractive index adjustable between less than, and no less than, a critical value, configured such that a light incident into the convex lens has a total reflection if the refractive index of the refractive index-adjustable layer is less than the critical value, and transmits through the refractive index-adjustable layer and reaches the light-absorbing layer for absorption if the refractive index of the refractive index-adjustable layer is no less than the critical value. The critical value can be a refractive index of the convex lens if it is in direct contact with the refractive index-adjustable layer, or can be a refractive index of a transparent film layer disposed between the convex lens and the refractive index-adjustable layer and in direct contact with the refractive index-adjustable layer.