| abstract |
An optical probe, which is particularly suited to for use in measurements on tissue material of a patient. In one embodiment, the probe comprises upper and lower housing elements incorporating a light energy source and corresponding detector. The tissue material of the patient is disposed between the upper and lower housing elements such that the light energy emitted by the source passes through the tissue material to the detector. A plurality of light shields are attached to one or both of the housing elements to reduce the amount of ambient and reflected light reaching the detector. Additionally, various portions of the upper and lower housing elements and shields utilize light absorbent coloration and/or coatings which further mitigate the effects of undesired ambient and reflected light, thereby reducing noise generated within the instrument and increasing its accuracy. In one embodiment, the light shields are made removable from the optical probe, thereby facilitating replacement. A circuit for monitoring the condition of the probe, and indicating when replacement of the probe is desirable, is also disclosed. |