| 摘要 |
<p>An illuminator comprises a unit (18) for splitting an incident energy beam (57) from a laser light source reflected from reflectors (48a, 48b, 48c) into a plurality of light beams, making mutually different the optical path lengths of the split light beams from the laser light source to the illuminated face and imparting differences of optical path length (difference of optical path) longer than the temporal coherence length. Consequently, generation of speckles (interference fringes) deteriorating the uniformity of illuminance on the illuminated face can be suppressed. Since reflectors having reflectance of 95% or above can be employed as the ones constituting the light beam splitting unit (18), the loss of the quantity of light is reduced and an abundant quantity of illumination light can be supplied to the illuminated face. Such suppression of speckles is especially advantageous when laser light having high spatial coherence is employed.</p> |
