Why is the shadow clear under an incandescent light, but not under a fluorescent light?

This is the difference between a point light source and a surface light source, incandescent lamp can be seen as a point light source, so that the object's blocking the formation of black shadow is a single, and fluorescent lamps can be seen as a surface light source, equivalent to a lot of point light source, the different point light source in the object blocking the light will form a lot of black shadows, but the boundaries of these shadows must be staggered, then, outside the junction of the shadow there is a portion of the light irradiated, combined, will cause the shadow of the fluorescent lamp is not clear phenomenon. The shadow of the fluorescent lamp is not clear phenomenon, the shadowless lamp used in hospitals is this principle, the shadowless lamp is a surface light source composed of many lights!