A backlight of the present invention has a panel case and phosphor-coated anode section arranged in the panel case and linear cathode section. The linear cathode section has a conductive wire having carbon nano-wall formed on its outer peripheral surface. A field electron emitter emits electrons toward the phosphor-coated anode section so as to be radially widespread, when DC voltage is applied between the phosphor-coated anode section and the linear cathode section.