Eyepiece optical system and observation apparatus
AssigneeCanon Kabushiki Kaisha
InventorAi Takumi
Life of this patent
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Abstract
The present invention provides an eyepiece optical system for observing an image displayed on an image display surface. The eyepiece optical system includes a first lens having a positive refractive power, a second lens having a negative refractive power, and a third lens having a positive refractive power, which are arranged in this order from an image display surface side to an observation side. A focal length of the first lens, a focal length of the third lens, a curvature radius of a lens surface on the observation side of the first lens, and a curvature radius of a lens surface on the image display surface side of the second lens are appropriately set.
Claims8
An eyepiece optical system for observing an image displayed on an image display surface, the eyepiece optical system comprising:
- a first lens having a positive refractive power, a second lens having a negative refractive power, and a third lens having a positive refractive power arranged in this order from an image display surface side to an observation side, wherein
- the following conditional expressions are satisfied:
- 0.450≤f1/f3≤0.880;
- and
- 0.160<(L2R1−L1R2)/(L2R1+L1R2)≤0.294
- where f1 represents a focal length of the first lens, f3 represents a focal length of the third lens, L1R2 represents a curvature radius of a lens surface on the observation side of the first lens, and L2R1 represents a curvature radius of a lens surface on the image display surface side of the second lens.
An observation apparatus comprising:
- an image display element configured to display an image;
- and
- an eyepiece optical system used to observe an image displayed on an image display surface of the image display element, wherein
- the eyepiece optical system includes a first lens having a positive refractive power, a second lens having a negative refractive power, and a third lens having a positive refractive power arranged in this order from the image display surface of the image display element to an observation side, and
- the following conditional expressions are satisfied:
- 0.450≤f1/f3≤0.880;
- and
- 0.160<(L2R1−L1R2)/(L2R1+L1R2)≤0.294
- where f1 represents a focal length of the first lens, f3 represents a focal length of the third lens, L1R2 represents a curvature radius of a lens surface on the observation side of the first lens, and L2R1 represents a curvature radius of a lens surface facing on the image display surface of the second lens.
Dependencies are inferred from the claim text.