A zoom lens with a bent optical path comprising, in order from the object side to the image side, a first lens unit having a positive refractive power, a second lens unit having a negative refractive power, and a rear lens unit group having a positive refractive power as a whole. The invention can be implemented for use with standard MHP or OCAP receivers, without the need for a backchannel or specialized hardware. The hollow portion is defined in the radiation part, and comprises a first slot connected to a second slot, which is connected to a third slot, wherein the second slot extends between the first slot and the third slot forming a substantially h-shaped pattern. Two check valves prevent flow from the used dialysate line towards the two discharge ports. The method then updates the luminance of the appended region.