Optical system for an endoscope
A lens assembly of a viewing element for an endoscope has lenses and a barrel containing the lenses. The internal surface of the barrel is shaped in accordance with the relative position and size of the lenses and a lens holder encompassing at least a portion of the barrel. The barrel and/or the lens holder are injection-molded and can be variably positioned relative to each other. An optional adhesive layer that reduces or eliminates small particles from the viewing element is positioned on an inner surface of the barrel and/or lens holder and used to remove any internal particulate matter that may otherwise obstruct the field of view.
1 . A lens assembly for use in a medical device, the lens assembly comprising: a barrel having a length, a proximal end, a distal end, a radially inward facing surface, and a radially-outward facing surface, wherein the radially inward facing surface includes: a distal tip configured to receive a first lens, a first projection extending radially inward relative to the distal tip and positioned proximal from the distal tip, wherein a second lens abuts a radially inward facing surface of the first projection, a second projection extending radially inward relative to the first projection and positioned proximal from the first projection, wherein the second projection abuts a proximal facing surface of a third lens, and a proximal end positioned radially outward from the distal tip, the first projection, and the second projection; a plurality lenses in the barrel, wherein a profile of the radially inward facing surface of the barrel is configured to receive and hold the plurality of lenses, and each of the plurality of lenses abuts the radially inward facing surface of the barrel, the plurality of lenses comprising: the first lens, the second lens, and the third lens; and a holder having a radially inward facing surface, a proximal end, and a distal end, wherein the barrel is received within the holder.
2 . The lens assembly of claim 1 , wherein the first projection and the second projection are formed by any one or a combination of milling, turning, injection molding, metal injection molding (MIM), and casting.
3 . The lens assembly of claim 1 , wherein the radially-outward facing surface of the barrel includes a first radially-outward facing surface and a second radially-outward facing surface; and wherein the first radially-outward facing surface is positioned radially-outward, relative to a central longitudinal axis of the barrel, from the second radially-outward facing surface.
4 . The lens assembly of claim 1 , wherein the radially inward facing surface includes an exposed adhesive layer configured to grab and hold loose particles.
5 . The lens assembly of claim 1 , further comprising a protective glass and a detector at the proximal end of the holder.
6 . The lens assembly of claim 1 , wherein the second projection includes a first surface substantially perpendicular to a central longitudinal axis of the barrel and a second proximal-facing surface angled relative to the distal facing surface.
7 . The lens assembly of claim 1 , wherein the barrel has a wall thickness, measured in a direction perpendicular to a central longitudinal axis of the barrel, which varies along a length of said barrel, wherein a thickest portion of the barrel is at the second projection.
8 . The lens assembly of claim 1 , wherein the radially outward facing surface of the barrel and the radially inward facing surface of the holder are substantially smooth to allow for movement of the barrel relative to the holder.
9 . The lens assembly of claim 1 , wherein the radially inward facing surface further comprises a third projection positioned proximal from the second projection, wherein the third projection is (i) radially inward relative to the proximal end and (ii) radially outward relative to the first projection and the second projection.
10 . The lens assembly of claim 1 , wherein the barrel comprises a non-reflective material configured to reduce reflections within the lens assembly.
11 . A lens assembly for use in a medical device, the lens assembly comprising: a barrel having a length, a proximal end, a distal end, a radially inward facing surface, and a radially-outward facing surface, wherein the radially inward facing surface includes: a distal tip configured to receive a first lens, a first projection extending radially inward relative to the distal tip, wherein the first projection abuts a proximal facing surface of the first lens, a second projection extending radially inward relative to the first projection, wherein the second projection abuts a proximal facing surface of a second lens; and a proximal end positioned radially outward from the distal tip, the first projection, and the second projection; a plurality lenses in the barrel, wherein a profile of the radially inward facing surface of the barrel is configured to receive and hold the plurality of lenses, and each of the plurality of lenses abuts the radially inward facing surface of the barrel, the plurality of lenses comprising: the first lens, and the second lens, a holder having a radially inward facing surface, a proximal end, and a distal end, wherein the barrel is received within the holder.
12 . The lens assembly of claim 11 , further comprising a detector array at the proximal end of the holder.
13 . The lens assembly of claim 11 , wherein the first projection and the second projection are formed by any one or a combination of milling, turning, injection molding, metal injection molding (MIM), and casting.
14 . The lens assembly of claim 11 , wherein the second projection includes a first surface substantially perpendicular to a central longitudinal axis of the barrel and a second proximal-facing surface angled relative to the distal facing surface.
15 . The lens assembly of claim 11 , wherein the radially outward facing surface of the barrel and the radially inward facing surface of the holder are substantially smooth to allow for movement of the barrel relative to said holder.
16 . The lens assembly of claim 11 , wherein the radially outward facing surface of the barrel includes a first portion with a first diameter and a second portion with a second diameter, wherein the first diameter is larger than the second diameter.
17 . The lens assembly of claim 11 , wherein an adhesive layer is coupled to the radially inward facing surface of the barrel, and wherein a radially inward facing portion of the adhesive layer remains exposed and is configured to grab and hold loose particles.
18 . The lens assembly of claim 11 , wherein the radially inward facing surface of the barrel includes:
a first surface with a first diameter;
a second surface with a second diameter;
a third surface with a third diameter;
a fourth surface with a fourth diameter; and
a fifth surface with a fifth diameter;
wherein each of the first surface, the second surface, the third surface, the fourth surface, and the fifth surface extends substantially parallel to a central longitudinal axis of the barrel; and
wherein each of the first diameter, the second diameter, the third diameter, the fourth diameter, and the fifth diameter is different from each other.
19 . A lens assembly for use in a medical device, the lens assembly comprising: a barrel having a length, a proximal end, a distal end, a radially inward facing surface, and a radially-outward facing surface, wherein the radially inward facing surface includes: a distal tip configured to receive a first lens, a first projection extending radially inward relative to the distal tip, wherein the first projection abuts a proximal facing surface of the first lens, a second projection extending radially inward relative to the first projection, wherein the second projection abuts a proximal facing surface of a second lens; and a proximal end positioned radially outward from the distal tip, the first projection, and the second projection; and a plurality lenses in the barrel, wherein a profile of the radially inward facing surface of the barrel is configured to receive and hold the plurality of lenses, and each of the plurality of lenses abuts the radially inward facing surface of the barrel, the plurality of lenses comprising: the first lens, and the second lens.
20 . The lens assembly of claim 19 , wherein an adhesive layer is coupled to the radially inward facing surface of the barrel, and wherein a radially inward facing portion of the adhesive layer remains exposed and is configured to grab and hold loose particles.