Eyepiece lens, observation apparatus, and imaging apparatus including the same
AssigneeCanon Kabushiki Kaisha
InventorsJun Kawamura, Nobuyuki Miyazawa, Yu Inomoto
Life of this patent
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Abstract
One or more eyepiece lenses, one or more observation apparatuses and one or more imaging apparatuses are discussed herein. In at least one embodiment, an eyepiece lens comprises, in order from an object side to an observation side, a first lens having a positive refractive power, a second lens having a negative refractive power, a third lens having a positive refractive power, a fourth lens having a negative refractive power, and a fifth lens having a positive refractive power, wherein a focal length of the fifth lens is shorter than a focal length of the third lens, and the focal length of the third lens is shorter than a focal length of the first lens.
Claims10
An eyepiece lens consisting of:
- a first lens having a positive refractive power;
- a second lens having a negative refractive power disposed adjacent to an observation side of the first lens;
- a third lens having a positive refractive power disposed adjacent to an observation side of the second lens;
- a fourth lens having a negative refractive power disposed adjacent to an observation side of the third lens;
- and
- a fifth lens having a positive refractive power disposed adjacent to an observation side of the fourth lens,
- wherein a focal length of the fifth lens is shorter than a focal length of the third lens, and the focal length of the third lens is shorter than a focal length of the first lens, and
- wherein the following conditional expression is satisfied:
- 0.53<f5/f<0.95,
- where a focal length of the eyepiece lens is defined as f, and the focal length of the fifth lens is defined as f5.
An observation apparatus comprising:
- an image display device configured to display an image;
- and
- an eyepiece lens used to observe an image displayed on an image display surface of the image display device, the eyepiece lens consisting of a first lens having a positive refractive power, a second lens having a negative refractive power disposed adjacent to an observation side of the first lens, a third lens having a positive refractive power disposed adjacent to an observation side of the second lens, a fourth lens having a negative refractive power disposed adjacent to an observation side of the third lens, and a fifth lens having a positive refractive power disposed adjacent to an observation side of the fourth lens,
- wherein a focal length of the fifth lens is shorter than a focal length of the third lens, and the focal length of the third lens is shorter than a focal length of the first lens, and
- wherein the following conditional expressions are satisfied:
- 0.52<H/f<0.91, and
- 0.53<f5/f<0.95,
- where a focal length of the eyepiece lens is defined as f, a diagonal length of the image display surface is defined as H, and the focal length of the fifth lens is defined as f5.
An imaging apparatus comprising:
- an image sensor;
- a photographic optical system configured to form an object image on the image sensor;
- an image display device configured to display the object image;
- and
- an eyepiece lens used to observe an object image displayed on an image display surface of the image display device, the eyepiece lens consisting of a first lens having a positive refractive power, a second lens having a negative refractive power disposed adjacent to an observation side of the first lens, a third lens having a positive refractive power disposed adjacent to an observation side of the second lens, a fourth lens having a negative refractive power disposed adjacent to an observation side of the third lens, and a fifth lens having a positive refractive power disposed adjacent to an observation side of the fourth lens,
- wherein a focal length of the fifth lens is shorter than a focal length of the third lens, and the focal length of the third lens is shorter than a focal length of the first lens, and
- wherein the following conditional expression is satisfied:
- 0.53<f5/f<0.95,
- where a focal length of the eyepiece lens is defined as f, and the focal length of the fifth lens is defined as f5.
Dependencies are inferred from the claim text.