| 摘要 |
<p>In a first optical system (4), a coherent light from a light source unit (2) is introduced along a cyclic route (T0) and a mirror surface (432) of a tilt mirror (43) is arranged at such an optical position that an erect image of itself is formed while being shifted on the cyclic route (T0) and superimposed. At a slit (431) formed on the tilt mirror (43), the coherent light is divided into a plurality of light beams and the plurality of light beams are superimposed. The light path difference between arbitrary two optical beams from the incident position of the coherent light to the first optical system (4) and the slit (431) is set longer than the coherence length of the coherent light. As a result, in an illumination device (1), it is possible to obtain an illumination light having a uniform intensity distribution while preventing generation of a speckle.</p> |
