Variable direction of view instrument with distal image sensor

1. A viewing instrument having a variable direction of view, comprising:

an endoscopic device comprising;

a shaft having a distal end and a longitudinal axis;

a sensor mounted in the distal end of said shaft, said sensor having an image plane substantially parallel to the longitudinal axis of said shaft; and

a reflecting assembly for reducing the angle of incidence of incoming light onto the image plane of the sensor by increasing the path length travelled by the incoming light, comprising:

a first reflecting element boated at the distal end of sad shaft that receives incoming light and redirects the light in a direction generally perpendicular to the longitudinal axis of said shaft and wherein said element rotates about a rotational axis substantially perpendicular to the longitudinal axis of said shaft;

a second reflecting element that receives the light redirected by said first reflecting element and redirects the light in a direction generally parallel to the longitudinal axis of said shaft and toward the distal and of said shaft; and

a third reflecting element that receives the light redirected by said second reflecting element and redirects the light onto the image plane of said sensor.

2. The viewing instrument of claim 1 , wherein the reflecting element comprises a right-angled prism.

3. The viewing instrument of claim 1 , further comprising:

a negative lens located adjacent said reflecting element through which the incoming light is transmitted to said reflecting element.

4. The viewing instrument of claim 3 , wherein said negative lens has an optical axis substantially perpendicular to said rotational axis.

5. The viewing instrument of claim 1 , wherein in reflective element includes an aperture stop.

6. The viewing instrument of claim 1 , further comprising an actuator mounted in said shaft for rotating said reflecting element about said rotational axis.

7. The viewing instrument of claim 6 , wherein said actuator comprises a drive shaft that rotates about said longitudinal axis, further comprising a gear driven by said rotating drive shaft and connected to said reflecting element.

8. The viewing instrument of claim 6 , wherein said actuator comprises a motor arranged in said shaft and a drive gear rotated about said longitudinal axis by said motor, further comprising a second gear driven by said drive gear and coupled to said reflecting element.

9. The viewing instrument of claim 6 , wherein said actuator comprises a hollow shaft motor that rotates about said rotational axis and is coupled to said reflecting element.

10. The viewing instrument of claim 1 , wherein said shaft comprises an endoscope shaft.

11. The viewing instrument of claim 1 , wherein said first, second, and third reflecting elements each comprise a right-angled prism.

12. The viewing instrument of claim 1 , wherein said second reflecting element and said third reflecting element are arranged so that the path length traveled by the incoming light is approximately 30% more than if the incoming light were redirected from the first reflecting element directly to the image plane of said sensor.

13. The viewing instrument of claim 1 , wherein said first, second, and third reflecting elements are arranged so that the angle of incidence of incoming light onto the image plane of the sensor is less than 15 degrees.

14. The viewing instrument of claim 6 , wherein said second reflecting element is disposed between said actuator and said sensor in said shaft.