Endoscope light source unit with light quantity control

1. An endoscope light source unit for making illumination light from a light source incident on an incident end face of a light guide connected thereto, said endoscope light source unit comprising:

an aperture device having a plurality of aperture openings of different opening ratios, for selectively positioning one of said aperture openings between said incident end face of said light guide and said light source;

a reading device for reading information on an illumination light quantity limit from a memory provided in a scope which is connected to said endoscope light source unit; and

a controller for selecting an opening ratio of said aperture device in accordance with said information on said illumination light quantity limit read by said reading device, wherein said controller controls said aperture device so as not to position any of said aperture openings, which have an opening ratio higher than said selected opening ratio, between said incident end face of said light guide and said light source;

wherein said aperture device comprises a disc and drive device for rotatably driving said disc, said aperture openings of different aperture ratios being formed in said disc at equi-angular intervals thereon about a center of rotation thereof; and

wherein said disc further comprises an aperture position hole for detecting an initial position of rotation of said disc.

2. The endoscope light source unit according to claim 1 , wherein said information on said illumination light quantity limit comprises identification information measured and set in advance in terms of light quantity and temperature.

3. The endoscope light source unit according to claim 1 ,

wherein said controller controls said drive device so that one of said aperture openings intersects an illumination optical path between said incident end face of said light guide and said light source.

4. The endoscope light source unit according to claim 3 , wherein each of said aperture openings comprises a plurality of small holes formed in said disc at predetermined intervals; and

wherein said opening ratios are determined by differing densities of said small holes.

5. The endoscope light source unit according to claim 3 , wherein each of said aperture openings comprises a plurality of small holes formed in said disc at predetermined intervals; and

wherein said opening ratios are determined by differing diameters of said small holes.

6. The endoscope light source unit according to claim 3 , wherein each of said aperture openings comprises a plurality of small holes formed in said disc at predetermined intervals; and

wherein said opening ratios are determined by differing densities and diameters of said small holes.

7. The endoscope light source unit according to claim 3 , wherein said small holes are circular in shape.

8. The endoscope light source unit according to claim 3 , wherein said small holes are polygonal in shape.

9. The endoscope light source unit according to claim 3 , further comprising:

an initial-position detection sensor which detects a initial position of said disc, wherein one of said plurality of aperture openings which have a smaller opening ratio than a maximum opening ratio intersects said illumination optical path between said incident end face of said light guide and said light source at said initial position;

wherein said maximum opening ratio of said aperture openings of said disc is an opening ratio which prevents an excessively large quantity of said illumination light from passing through said disc to provide a safe light quantity for any electronic scope which is connectable to said endoscope light source unit;

wherein said controller drives said drive device so as to rotate said disc so that said one of said plurality of aperture openings intersects said illumination optical path between said incident end face of said light guide and said light source.

10. The endoscope light source unit according to claim 9 , wherein an aperture opening having said maximum opening ratio or said one of said aperture openings which is smaller than said maximum opening ratio, intersects said illumination optical path between said incident end face of said light guide and said light source at said initial position.

11. An endoscope light source unit for making illumination light from a light source incident on an incident end face of a light guide connected thereto, said endoscope light source unit comprising:

an aperture device having a plurality of aperture openings of different opening ratios, for selectively positioning one of said aperture openings between said incident end face of said light guide and said light source;

a reading device for reading information on an illumination light quantity limit from a memory provided in a scope which is connected to said endoscope light source unit; and

a controller for selecting an opening ratio of said aperture device in accordance with said information read by said reading device, wherein said controller controls said aperture device so as not to position any of said aperture openings, which have an opening ratio higher than said selected opening ratio, between said incident end face of said light guide and said light source,

wherein said controller selects an opening ratio lower than a maximum opening ratio of said aperture device in the case where said reading device fails to read said information on the illumination light quantity limit from said memory.

12. The endoscope light source unit according to claim 11 , wherein the controller selects an opening ratio which is lower than said maximum opening ratio of said aperture device in the case where said controller determines via said reading device that no scope is connected to said endoscope light source unit.

13. The endoscope light source unit according to claim 12 , further comprising a display device for displaying a result of determination of the controller.

14. The endoscope light source unit according to claim 11 , wherein said controller selects an opening ratio which is lower than said maximum opening ratio of said aperture device in the case where said controller determines via said reading device that a fiber scope is connected to said endoscope light source unit.

15. The endoscope light source unit according to claim 14 , further comprising a display device for displaying a result of determination of the controller.

16. The endoscope light source unit according to claim 11 , wherein said information on the illumination light quantity limit comprises identification information measured and set in advance in terms of light quantity and temperature.

17. The endoscope light source unit according to claim 11 , wherein said aperture device comprises:

a disc and drive device for rotatably driving said disc, said aperture openings of different aperture ratios being formed in said disc at equi-angular intervals thereon about a center of rotation thereof; and

wherein said controller drives said drive device so that one of said aperture openings intersects an illumination optical path between said incident end face of said light guide and said light source.

18. The endoscope light source unit according to claim 17 , further comprising:

an initial-position detection sensor which detects a initial position of said disc, wherein one of said plurality of aperture openings which have a smaller opening ratio than a maximum opening ratio intersects said illumination optical path between said incident end face of said light guide and said light source at said initial position;

wherein said maximum opening ratio of said aperture openings of said disc is an opening ratio which prevents an excessively large quantity of said illumination light from passing through said disc to provide a safe light quantity for any electronic scope which is connectable to said endoscope light source unit;

wherein said controller drives said drive device so as to rotate said disc so that said one of said plurality of aperture openings intersects said illumination optical path between said incident end face of said light guide and said light source.

19. The endoscope light source unit according to claim 18 , wherein an aperture opening having said maximum opening ratio or said one of said aperture openings which is smaller than said maximum opening ratio, intersects said illumination optical path between said incident end face of said light guide and said light source at said initial position.

20. The endoscope light source unit according to claim 17 , further comprising:

a main switch for supplying power to said controller; and

a lamp switch for turning ON said light source,

wherein when said main switch is turned ON, said controller reads said information on the illumination light quantity limit, selects an opening ratio, and drives said drive device so that an aperture opening of said aperture device having the selected opening ratio intersects said illumination optical path between said incident end face of said light guide and said light source.