| 主权项 |
1. A luminous flux limit device that limits a luminous flux of an optical scanning unit, the luminous flux limit device comprising:
a body portion including an aperture; and a light-blocking portion to prevent light from being transmitted, wherein the aperture comprises:
a blocking region in which light is blocked by the light-blocking portion, anda transmissive region which is a region of the aperture excluding the blocking region, wherein the transmissive region is a flat continuous region surrounding the blocking region, wherein the blocking region is located in a central region of the aperture, wherein the transmissive region includes a first transmissive region and a second transmissive region, and the phases of the luminous fluxes of the first transmissive region and the second transmissive region are set to be different, wherein the first transmissive region surrounds the blocking region, the second transmissive region surrounds the first transmissive region, and wherein, if a radius of an outermost portion of the blocking region in a main scanning direction is ρ1m, a radius of an outermost portion of the first transmissive region in the main scanning direction is ρ2m, and a radius of an outermost portion of the second transmissive region in the main scanning direction is ρ3m, then ρ1m<ρ2m<ρ3m, 0.3≦ρ1m/ρ3m≦0.7, and 0.5≦ρ2m/ρ3m≦0.9 are satisfied. |
