When the writing and Book Light is in a normal sitting position, the inner wall of the lampshade and the light source should not be visible when the human eye is looking at the horizontal direction; The working area illuminated by the Book Light shall be 250lx - 500lx, and the minimum illumination shall be ≥ 120lx. It should be ensured that the illumination in the working area illuminated by the Book Light is relatively uniform, and no particularly bright or dark light spots can be generated. Only by ensuring these three basic optical performance requirements can eye fatigue be alleviated, and it can be called a writing and Book Light.