Sensor for performing medical measurements, particularly pulsoximetry measurements on the human finger

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS With the aid of the drawings two specific embodiments of pulsoximetry sensors will now be described, but it is obvious that the invention is not restricted to the pulsoximetry field.
The plan view of FIG.
1 shows a transmission sensor 1, in which is embedded a double light emitting diode or LED 2.
This LED operates in the red and infrared ranges, as is conventionally the case in pulsoximetry.
Only the first casing part 3 of the sensor 1 is visible in FIG.
1.
The sensor is connected to a monitor by means of a not shown cable running in the direction of the arrow K.
The cable is electrically connected to the light emitting diodes 2 and is inserted in a slot 4 of the sensor 1.
In the cross-section of FIG.
2 it is once again possible to see a double LED 2, which is located on the bottom of the slot 4 of the first casing part 3.
During application, the sensor is placed with a cylindrical concave surface 5 of the first casing part 3 on a finger or toe nail of a patient and is fixed there with an adhesive pad or a tissue-compatible adhesive.
In order that the light from the double LED 2 can pass through the fingernail into the finger tissue, a recess 6 must be provided.
Alternatively, at the location of reference numeral 6 can also be inserted transparent sensor material, such as e.
g.
transparent plastic.
The reference numeral 7 indicates an adhesive element or coating.
A second casing part 8 with elastic properties passes round the finger or toe and thus ensures the mechanical fixing.
Moreover, in the second casing part 8 is installed a photoreceiver (phototransistor, photodiode), which measures the intensity of the light radiated through the human tissue.
This receiver is designated 9 in FIG.
6 and is also electrically connected to the cable and therefore the monitor.
FIG.
7 diagrammatically shows the sensor 1 during the application to a human thumb 9.
The adhesive element (adhesive pad or coating) is located between the thumb nail 10 and the sensor