Method and apparatus for refection suppression in optical systems
OwnerMoshe Benezrainventor
Life of this patent
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Abstract
A method and apparatus to suppress stray light refection in enclosures of optical trains are presented. Unlike prior-art that relies on absorption to suppress stray light the presented invention relies on reflections in a tapered enclosure to prevent stray light from reaching the sensor. The presented invention also provides a method to reshape the tapered enclosure into more convenient shapes using Fresnel Design. The presented invention can be realized in different ways including but not limited to (1) a monolithic enclosure, (2) a modular enclosure that can adapt to different lenses and or sensors, (3) a sleeve to be inserted into existing enclosure to enhance their performance.
Claims19
A Sequential optical system or a sequential part of an optical system comprising:
- a) An enclosure or housing (enclosure) having walls and an inner volume in which light travels through—or
- b) A light conduit having an inner volume and a boundary between the inner volume and its surroundings (conduit).
- wherein:
- a) The enclosure or the conduit can be divided into one or more segments along the optical axis such that:
- i. The surface of each segment is continuous.
- ii. Each segment has an entry clear aperture with diameter of Dentryi>0 and an exit clear aperture with diameter Dexiti>0, where i=1 . . . n is the segment number.
- iii. The cumulative magnification of all segments from Dentry1 to Dexitn is at least 2. That is
- D
- entry
- 1
- +
- ∑
- i
- =
- 1
- n
-
- (
- D
- exit
- i
- -
- D
- entry
- i
- )
- D
- entry
- 1
- ≥
- 2
A method of suppressing stray light reflection in a sequential optical system or part of an optical system by using a tapered enclosure or housing (enclosure) with a numerical aperture A at the entrance aperture of the enclosure and a numerical aperture B at the exit aperture such that 2A≤B.
Dependencies are inferred from the claim text.