Method and apparatus for refection suppression in optical systems
View Patent ↗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.
1. A Sequential optical system or a sequential part of an optical system comprising:
(a) an enclosure or housing comprising 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;
wherein:
said enclosure or the conduit can be divided into one or more segments along the optical axis
wherein:
i. the surface of each segment is continuous;
ii. each segment has an entry clear aperture with diameter of D i entry >0 and an exit clear aperture with diameter D i exit >0, where i=1 . . . n is the segment number;
iii. the cumulative magnification of all segments from D 1 entry to D n exit is at least 2; wherein [D 1 entry +Σ n i=1 (D i exit −D i entry )]/D 1 entry ≥2.
2. The sequential optical system of claim 1 , wherein the enclosure, housing or the conduit comprises one or more trimmed conical segments.
3. The sequential optical system of claim 2 , wherein all of the segments are identical conical segments.
4. The sequential optical system of claim 3 , wherein the enclosure, housing or conduit is a microscope lens tube.
5. The sequential optical system of claim 4 , wherein the microscope lens tube comprises an adapter for mounting one or more objective lens.
6. The sequential optical system of claim 4 , wherein the microscope lens tube comprises an adapter for mounting one or more cameras.
7. The sequential optical system of claim 3 , wherein the segments form a sleeve (S) wherein said sleeve has an outer diameter (SD) that is inserted into a tube (T) having an inner diameter TD, wherein SD≤TD where said sleeve S has a wall thickness (K) and wherein K≤0.2TD.
8. The sequential optical system of claim 7 , wherein the tube T is a lens tube for a microscope.
9. The sequential optical system of claim 7 , wherein the tube T is a lens or mirror tube for a telescope.
10. The sequential optical system of claim 3 , wherein the enclosure or housing or conduit is a telescope lens or mirror tube.
11. The sequential optical system of claim 9 , wherein said telescope lens or mirror tube comprises mounts to one of more cameras.
12. The sequential optical system of claim 1 , wherein the enclosure, housing or conduit comprises one or more pyramidal segments, wherein the apex of each pyramidal segment is trimmed.
13. The sequential optical system of claim 12 , wherein all the pyramidal segments are identical.
14. The sequential optical system of claim 12 , wherein the enclosure is for a telescope.
15. The sequential optical system of claim 12 , wherein the enclosure comprises mounts for mounting different cameras.
16. The sequential optical system of claim 12 , wherein the segments form a polyhedral sleeve (S) having an outer diameter (SD) that is inserted into a polyhedron enclosure (P) with inner diameter (PD), wherein SD≤PD and the sleeve (S) has wall thickness (K), K≤0.2PD.
17. The sequential optical system of claim 16 , wherein the enclosure P is for a telescope.
18. A method of suppressing stray light reflection in an optical comprising:
(a) providing a tapered enclosure wherein: said enclosure or the conduit can be divided into one or more segments along the optical axis wherein:
i. the surface of each segment is continuous;
ii. each segment has an entry clear aperture with diameter of D entry i >0 and an exit clear aperture with diameter D exit i >0, where i=1 . . . n is the is the segment number;
iii. the cumulative magnification of all segments from D entry 1 to D exit n is at least 2; wherein [D entry 1 +Σ i=1 n (D exit i −D entry i )]/D entry 1 ≥2;
(b) inserting said tapered enclosure into a microscope, telescope or sequential optical system wherein the tapered enclosure suppresses stray light reflections in said microscope, telescope or sequential optical system.