| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a video display device 1 of a wide image angle with a small-sized and compact configuration by developing a small-sized, compact and high-NA illumination optical system 12. <P>SOLUTION: The illumination optical system 12 which guides light from a light source 11 to a display element 14 includes a first group G1 which has positive power and has a reflection surface and a second group G2 which has positive power and has a fresnel lens 18. Thus, by making the illumination optical system 12 a positive and positive two-groups constitution, a larger NA can be secured while shortening the length of the illumination optical system 12 in the proceeding direction of light as compared with the case constituting the illumination optical system 12 with one optical element. Moreover, since the first group G1 has a reflection surface, the optical path of the illumination optical system 12 is folded and the illumination optical system 12 is made small. At this time, by satisfying a prescribed conditional relation, the illumination optical system 12 can be constituted compactly while securing a space into which the reflection surface is inserted. <P>COPYRIGHT: (C)2010,JPO&INPIT</p> |
