ENDOSCOPE OBJECTIVE LENS WITH LARGE ENTRANCE PUPIL DIAMETER AND HIGH NUMERICAL APERTURE
First Claim
Patent Images
1. An endoscope objective lens, comprising:
- a negative lens group, G1;
a positive lens group, G2; and
a stop, S, placed between the negative lens group, G1, and the positive lens group, G2,wherein the following conditions (1) to (4) are satisfied;
0.5<
EFL<
1.4 mm, −
4≦
F1/EFL≦
−
1.2, 1.1≦
F2/EFL≦
1.9
(1)
F#≦
4.2,
(2)
EPD≧
0.4 mm, 0.4≧
EPD/Dia≧
0.2
(3)
FFOV≧
120°
(4)and wherein,EFL is the effective focal length of the objective lens,F1 is the effective focal length of the positive lens group, G1,F2 is the effective focal length of the negative lens group, G2,F# is the f number of the objective lens,EPD is the entrance pupil diameter of the objective lens,Dia is the maximum diameter of the objective lens, andFFOV is the full field of view of the objective lens.
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Abstract
An endoscope objective lens for collecting combined bright field (white light) and fluorescence images includes a negative lens group, a stop, and a positive lens group. The lens has a combination of large entrance pupil diameter (≧0.4 mm) for efficiently collecting weak fluorescence light, large ratio between the entrance pupil diameter and the maximum outside diameter (Dentrance/Dmax larger than 0.2), large field of view (FFOV≧120°) and favorably corrected spherical, lateral chromatic and Petzval field curvature for both visible and near infrared wavelengths.
70 Citations
17 Claims
-
1. An endoscope objective lens, comprising:
-
a negative lens group, G1; a positive lens group, G2; and a stop, S, placed between the negative lens group, G1, and the positive lens group, G2, wherein the following conditions (1) to (4) are satisfied;
0.5<
EFL<
1.4 mm, −
4≦
F1/EFL≦
−
1.2, 1.1≦
F2/EFL≦
1.9
(1)
F#≦
4.2,
(2)
EPD≧
0.4 mm, 0.4≧
EPD/Dia≧
0.2
(3)
FFOV≧
120°
(4)and wherein, EFL is the effective focal length of the objective lens, F1 is the effective focal length of the positive lens group, G1, F2 is the effective focal length of the negative lens group, G2, F# is the f number of the objective lens, EPD is the entrance pupil diameter of the objective lens, Dia is the maximum diameter of the objective lens, and FFOV is the full field of view of the objective lens. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
-
Specification