OPTICAL DIAPHRAGM, LENS BARREL, AND IMAGING DEVICE OR PROJECTION DEVICE

An optical diaphragm device 10 of the present invention includes: a plurality of diaphragm blades 100 each of which has a first fixing boss 120 protruding from one surface of a first planar plate 102 toward a side in a first direction and a moving boss 130 protruding from the other surface of the first planar plate 102 toward a side in a second direction; a plurality of light leakage prevention blades 200 each of which has a second fixing boss 220 protruding from one surface of a second planar plate 202 toward the side in the first direction and forms a pair with the diaphragm blade 100; a drive ring 300 on which a plurality of first cam grooves 330 are formed; and a housing body 400 which houses the diaphragm blades 100, the light leakage prevention blades 200 and the drive ring 300. A second cam groove 230 is formed on the light leakage prevention blade 200. The moving boss 130 of the diaphragm blade 100 is inserted into the second cam groove 230 of the light leakage prevention blade 200, and is inserted into the first cam groove 330 of the drive ring 300. According to the optical diaphragm device 10 of the present invention, it is possible to provide an optical diaphragm device where a width of the diaphragm blade can be narrowed, and the number of diaphragm blades can be easily increased.