Constant Current Drive for Lasers in Photoplethysmography
AssigneeZynex Monitoring Solutions, Inc.
InventorJonas Alexander Pologe
Life of this patent
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Abstract
A photoplethysmographic monitor has two or more emitters wherein at least one of the emitters is a single longitudinal mode diode laser, electronic drive circuitry adapted to energize the at least one laser to a pre-determined constant current level, and a housing containing the at least one laser, the housing thermally coupled to a temperature-controlled element. The temperature-controlled element configured to hold the housing at a fixed temperature and the pre-determined constant current level of the at least one laser is selected to set the at least one laser, when energized and when held at the fixed temperature, to operate between longitudinal mode hop points of the at least one laser.
Claims20
A photoplethysmographic monitor, comprising:
- two or more emitters wherein at least one of the emitters is a single longitudinal mode diode laser;
- electronic drive circuitry adapted to energize the at least one laser to a pre-determined constant current level;
- and
- a housing containing the at least one laser, the housing thermally coupled to a temperature-controlled element;
- the temperature-controlled element configured to hold the housing at a fixed temperature;
- the pre-determined constant current level of the at least one laser is selected to set the at least one laser, when energized and when held at the fixed temperature, to operate between longitudinal mode hop points of the at least one laser.
A method of assembling a photoplethysmographic monitor, comprising:
- providing a housing comprising at least one single longitudinal mode diode laser within the housing, the monitor further including at least one additional emitter;
- thermally coupling the housing to a temperature-controlled element;
- adapting a temperature controller to set the temperature-controlled element to hold the housing at a fixed temperature;
- coupling electronic drive circuitry to the at least one laser, the electronic drive circuitry adapted to energize the at least one laser to a pre-determined constant current level;
- and
- setting the pre-determined constant current level of the at least one laser to a level between longitudinal mode hop points when energized and when held at the fixed temperature.
A photoplethysmographic monitor, comprising:
- two or more emitters wherein at least one of the emitters is a single longitudinal mode diode laser;
- electronic drive circuitry adapted to energize the at least one laser to a pre-determined constant current level;
- and
- a housing containing the at least one laser, the housing thermally coupled to a temperature-controlled element;
- the temperature-controlled element configured to hold the housing at a fixed temperature such that, when the at least one laser is energized to the pre-determined constant current level, the at least one laser operates between longitudinal mode hop points.
A method of assembling a photoplethysmographic monitor, comprising:
- providing a housing comprising at least one single longitudinal mode diode laser within the housing, the monitor further including at least one additional emitter;
- coupling electronic drive circuitry to the at least one laser, the electronic drive circuitry adapted to energize the at least one laser to a pre-determined constant current level;
- thermally coupling the housing to a temperature-controlled element;
- and
- adapting a temperature controller to set the temperature-controlled element to hold the housing at a fixed temperature such that, when the at least one laser is energized to the pre-determined constant current level, the at least one laser operates between longitudinal mode hop points.
Dependencies are inferred from the claim text.