1. A plastic optical fiber for a medical device lighting, comprising a core and a
cladding,
wherein said core is composed of a (co)polymer containing methyl methacrylate as a main component,
wherein said cladding is composed of a copolymer having a fluorine weight composition ratio of 60 to 74%, and
wherein said plastic optical fiber has a theoretical numerical aperture, NA, of 0.48 to 0.65.
2. The plastic optical fiber for a medical device lighting according to claim 1, wherein said cladding has a bending elastic modulus of 20 to 200 Mpa.
3. The plastic optical fiber for a medical device lighting according to claim 1 or 2, wherein said cladding is composed of a copolymer containing the following copolymerized components:
10 to 30 wt% of hexafluoropropylene,
45 to 75 wt% of tetrafluoroethylene,
10 to 35 wt% of vinylidene fluoride, and
1 to 10 wt% of perfluoroalkylvinylether;
wherein said cladding is composed of a copolymer having a fluorine weight composition ratio of 70 to 74%; and
wherein said plastic optical fiber for a medical device lighting has a theoretical numerical aperture, NA, of 0.60 to 0.65.
4. The plastic optical fiber for a medical device lighting according to any one of
claims 1 to 3, wherein said cladding is composed of a copolymer containing the
following copolymerized components:
14 to 25 wt% of hexafluoropropylene,

49 to 70 wt% of tetrafluoroethylene, 14 to 30 wt% of vinylidene fluoride, and 2 to 7 wt% of perfluoroalkylvinylether.
5. The plastic optical fiber for a medical device lighting according to any one of claims 1 to 4, wherein said cladding has a thickness of 2 to 20 \xm.
6. The plastic optical fiber for a medical device lighting according to any one of claims 1 to 5, further comprising one or more cladding layers outside of said cladding, wherein the outermost cladding layer is composed of a copolymer containing
10 to 35 wt% of ethylene, 45 to 69 wt% of tetrafluoroethylene, 20 to 45 wt% of hexafluoropropylene, and
0.01 to 10 wt% of a. fluorovinyl compound represented by Equation (1) CH2 = CX^CFi^X2 (1) '
(wherein X1 represents a fluorine atom or hydrogen atom; X2 represents a fluorine atom, hydrogen atom, or carbon atom; and n is an integer of 1 to 10.)
7. A medical device lighting, comprising a light source and a light guide which transmits light from said light source to an end of said light guide and radiates said light to an irradiated object, wherein said light guide comprises said plastic optical fiber according to any one of claims 1 to 6.
8. The medical device lighting according to claim 7, wherein the number of said plastic optical fibers is ten or less.
9. The medical device lighting according to claim 7 or 8, wherein the number of said plastic optical fiber is one.
10. The medical device lighting according to any one of claims 7 to 9, wherein said plastic optical fiber has an outer diameter of 0.1 mm or more and 2.0 mm or less.
11. The medical device lighting according to any one of claims 7 to 10, comprising

an observation probe having an outer diameter of 7 mm or less.
12. The medical device lighting according to any one of claims 7 to 11, further comprising a lens for lighting, said lens for lighting being disposed on the end face of said end of said light guide, wherein the major axis diameter, FLL, of said end face and the minor axis diameter, FLs, of said end face have a relationship of 0.9 < FLs / FLL<1.
13. The medical device lighting according to any one of claims 7 to 11, further comprising a lens for lighting, said lens for lighting being disposed on said end face of said end, wherein the light guide side of said lens for lighting has a concave surface, and wherein the curvature radius, Rs, of the minor axis of the lens and the minor axis diameter, FLs, of said end face of said light guide have a relationship of Rs / FL3 > 0.7.
14. The medical device lighting according to any one of claims 7 to 11, further comprising a lens for lighting, said lens for lighting being disposed on said end, wherein the plastic optical fiber side of said lens for lighting has a plane surface.
15. The medical device lighting according to any one of claims 7 to 11, not comprising a lens for lighting on said end.
16. The medical device lighting according to any one of claims 7 to 15, wherein the medical device is an endoscope.
17. The medical device lighting according to claim 16, wherein an observation probe of said endoscope can be inserted into the bile duct or the pancreatic duct.