| 摘要 |
A handheld device for sensing and indicating the location of a blood vessel, and marking the skin adjacent to the blood vessel. The operation of the device is based on determining the difference in signal transfer amplitude between two partially overlapping infrared light paths, and moving the device until this difference is zeroed. The sensitivity of the device is enhanced by having an angle in each infrared light path such that the infrared light is primarily reflected, rather than absorbed, by the blood vessel.
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