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US 8,014,084 B2Granted
Optics for an extended depth of field
AssigneeDigitalOptics Corporation International
InventorsAlex Alon, Irina Alon, Haim Bezdin
Life of this patent
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Abstract
An optical imaging assembly having cylindrical symmetry, comprising a plurality of lenses having surfaces with curvatures and spacings between the surfaces, such that an optical image formed by the plurality of lenses has a defocus aberration coefficient greater than 0.1 at a focal plane of the assembly.
Claims20
An optical assembly, comprising:
- a first lens having positive refractive power and at least two aspheric surfaces, the first lens is located at a first distance from an aperture on an optical axis common to the first lens and the aperture, the optical axis being substantially cylindrically-symmetric;
- a second lens having negative refractive power and at least two aspheric surfaces, the second lens is meniscus-shaped near the optical axis and is located at a second distance from the first lens on the optical axis;
- and
- a third lens having positive refractive power and at least two aspheric surfaces, the third lens is meniscus-shaped near the optical axis and is located at a third distance from the second lens on the optical axis, wherein
- a real image of an object produced by the optical assembly has a defocus aberration coefficient greater than 0.1 at a focal plane of the optical assembly.
2 more elements
A method, comprising:
- collecting optical radiation impinging on an aperture, a portion of the optical radiation emanating from an object;
- propagating the optical radiation through an optical assembly comprising a set of at least three lenses and an infra-red filter, the optical assembly having substantially cylindrical symmetry with respect to a common optical axis, and a lens in the set having at least two aspheric surfaces;
- detecting at least a portion of the optical radiation at an image sensor defining a focal plane;
- and
- based on the detected portion of the optical radiation, producing an image of the object having:
- a modulation transfer function for spatial frequencies greater than 50 cycles per millimeter having at least one value smaller than or equal to about 0.35;
- and
- a point spread function greater than or equal to about 14 μm on the focal plane.
5 more elements
Dependencies are inferred from the claim text.