Variable aperture sensor

1. A pulse oximetry sensor comprising:

a first jaw;

an emitter disposed in said first jaw;

a second jaw rotatably attached to said first jaw;

a detector disposed in said second jaw; and

a variable aperture disposed in said second jaw,

said jaws adapted to attach to a tissue site so that said emitter transmits optical radiation into said tissue site and said detector receives optical radiation through said variable aperture after absorption by said tissue site,

said variable aperture configured to adjust the amount of said optical radiation received by said detector.

2. The pulse oximetry sensor according to claim 1 wherein said variable aperture comprises:

a fixed aperture defined by said second jaw;

a slide movable between a wide open position and a stopped down position, said wide open position adapted to pass maximal optical radiation to said detector, said stopped down position adapted to pass minimal optical radiation to said detector;

an open portion defined by said slide and generally aligned with said fixed aperture in said open position; and

a light block portion of said slide generally aligned with said fixed aperture in said stopped down position.

3. The pulse oximetry sensor according to claim 2 wherein said slide comprises:

a grip adapted for manually positions said slide; and

an extension extending from said grip and overlapping with said fixed aperture.

4. The pulse oximetry sensor according to claim 1 wherein said variable aperture comprises:

a fixed aperture defined by second jaw; and

a shutter installed within said fixed aperture,

said shutter movable between a wide open position and a stopped down position,

said wide open position adapted to pass maximal optical radiation to said detector, said stopped down position adapted to pass minimal optical radiation to said detector.

5. The pulse oximetry sensor according to claim 4 wherein said shutter comprises:

a lever; and

a plurality of leaves disposed within said fixed aperture,

said lever configured to position said leaves, said lever adapted to manually move between a first position corresponding to said open position and a second position corresponding to said stopped down position.

6. The pulse oximetry sensor according to claim 1 , wherein said variable aperture is configured to receive manual adjustment of the amount of said optical radiation received by said detector.

7. A pulse oximetry sensor method comprising the steps of:

emitting optical radiation into a tissue site from a first jaw of a housing;

manually varying a size of an aperture, said size responsive to tissue site physical and physiological characteristics, said manual varying adjusting attenuation of said optical radiation;

detecting, at a second jaw of said housing hingably attached to said first jaw, said optical radiation that has passed through said aperture and been absorbed by said tissue site; and

generating a physiological signal responsive to said absorption.

8. A pulse oximetry sensor method according to claim 7 wherein said manually varying a size of said aperture comprises manually varying a size of a fixed aperture.

9. A pulse oximetry sensor method according to claim 8 wherein said manually varying comprises altering a shutter opening within said fixed aperture.

10. A pulse oximetry sensor method according to claim 8 wherein said manually varying comprises sliding a light block across said fixed aperture.

11. A pulse oximetry sensor comprising:

means for transmitting optical radiation into a tissue site;

means for receiving said optical radiation after absorption by said tissue site;

means for positioning said means for transmitting and said means for receiving on said tissue site including a clam shell housing configured to substantially close around said tissue site; and

an intensity adjuster for manually adjusting an intensity of said optical radiation incident on said means for receiving, said intensity adjuster comprising one or more devices configured to vary a size of an aperture through which said optical radiation passes.

12. The pulse oximetry sensor according to claim 11 wherein said aperture comprises a fixed aperture and said intensity adjuster comprises:

means for passing said optical radiation between said tissue site and said means for receiving; and

means for variably reducing said fixed aperture means.

13. The pulse oximetry sensor according to claim 12 wherein said means for variably reducing comprises a sliding light block that covers a portion of said fixed aperture.

14. The pulse oximetry sensor according to claim 12 wherein said means for variably reducing comprises a shutter that reduces an opening of said fixed aperture.