LAMP DEVICE

摘要

Light use efficiency of a high-pressure discharge lamp is improved without using a sub-reflecting mirror or an auxiliary reflecting mirror, even when a size of a reflecting mirror is reduced. A prism surface (12S) is formed on the outer circumference surface of a light emitting section (4). The prism surface has an angle for reflecting or refracting at least a part of light not reflected by a concave reflecting mirror (3) out of light radiated from the light emitting section (4) toward a light collecting area (SP), which is formed in front of the lamp and has a prescribed size, at the time of reflecting a part of light, which is radiated from the light emitting section (4) toward the periphery of the light emitting section in a front-rear direction within a prescribed angle range by the concave reflecting mirror (3), and irradiating a light collecting area (SP) with the reflected light.