Projection optical system and image projection apparatus
AssigneeSony Corporation
InventorsJun Nishikawa, Nobuhiko Nishiki, Yasunori Kuratomi, Tetsuya Kita, Takaaki Iwaki
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Abstract
A projection optical system and an image projection apparatus that are small in size and can achieve projection with a wide angle while a good image forming performance is assured includes a first lens group having a negative refracting power and a second lens group also having a negative refracting power. The first and second lens groups are arranged in order from the projection side. The first lens group includes a negative meniscus lens that has a concave surface directed to the projection side and formed as an aspherical reflecting surface.
Claims18
A projection optical system of the retrofocus type, comprising:
- a first lens group having a negative refracting power;
- and
- a second lens group having a negative refracting power;
- said first and second lens groups being arranged in order from a projection side, and
- said first lens group including a negative meniscus lens having a concave surface directed to the projection side and formed as an aspherical reflecting surface.
An image projection apparatus, comprising:
- an image formation section for forming an image;
- and
- a projection optical system for projecting the image formed by said image formation section;
- said projection optical system being of a retrofocus type that includes a first lens group having a negative refracting power and a second lens group having a negative refracting power, said first and second lens groups being arranged in order from a projection side, said first lens group including a negative meniscus lens that has a concave surface directed to a projection side and formed as an aspherical reflecting surface.
Dependencies are inferred from the claim text.