Patent ID: 11868035
Assignee: RICOH INDUSTRIAL SOLUTIONS INC.
Field: Optics (Instruments)
Classification: CPC G | IPC G

Claim 0:
1. A projection optical system that projects an image, the projection optical system comprising: a refractive optical system and a refractive/reflective optical element arranged in sequence from an image display surface toward a projection receiving surface, wherein the refractive optical system includes a plurality of lenses, wherein the refractive/reflective optical element includes an optical element unit that includes a reflection surface member including a reflection surface, and a refractive medium portion that is in tight contact with the reflection surface, the refractive medium portion includes an incidence surface and an emergence surface, and the reflection surface is a curved surface having refractive power, wherein an image-forming light beam emerging from the refractive optical system is caused to enter the refractive/reflective optical element from the incidence surface of the refractive medium portion, reflected by the reflection surface, caused to emerge from the emergence surface of the refractive medium portion, and formed into an image on the projection receiving surface as a projection image, wherein one or more intermediate images of the image displayed on the image display surface are formed between the refractive optical system and the emergence surface of the refractive/reflective optical element, and wherein one or two of the one or more intermediate images are in the refractive medium portion of the refractive/reflective optical element.