LED characterization and compensation methods and systems

A method of monitoring an optical component of a diagnostic instrument, the method comprising:

• starting-up, operating, or starting-up and operating an LED to provide a photonic output;
• measuring, with a control unit operably coupled to the LED, a voltage across the LED operating at a given current, wherein the voltage across the LED is within a voltage range, and wherein measuring the voltage across the LED comprises:
• monitoring the entire voltage range at a first resolution, and
• monitoring a sub-range at a second resolution higher than the first resolution;
• and
• correlating the voltage to a junction temperature of the LED such that the voltage is a proxy of the junction temperature.

A diagnostic instrument comprising:

• an LED configured to provide an optical output for excitation of a biological sample received within the instrument for an assay to detect a target analyte;
• an optical detector configured to detect reactions in the sample in response to optical excitation to detect the target analyte;
• and
• a control unit having a processor and a voltage sensor, the control unit configured to operate the LED to monitor performance of the assay, wherein the processor includes instructions recorded thereon configured for:
• measuring a voltage across the LED during operation at a given current;
• correlating the voltage to a junction temperature of the LED such that the voltage is a proxy of the junction temperature;
• determining fluctuations in the junction temperature of the LED in real-time;
• and
• controlling operation of the LED based on the real-time determinations to compensate for fluctuations in photonic output of the LED due to changes in the junction temperature;
• wherein the control unit is configured such that the voltage across the LED is within a voltage range, wherein the control unit is further configured to:
• monitor the entire voltage range at a first resolution, and
• monitor a sub-range at a second resolution higher than the first resolution.

A method of operating an LED in a diagnostic instrument, the method comprising:

• operating, with a control unit, the LED of the diagnostic instrument, to provide an optical output for excitation of a biological sample received within the instrument for an assay to detect a target analyte;
• operating, with the control unit, an optical detector to detect reactions in the sample in response to optical excitation to detect the target analyte;
• measuring, with the control unit, a voltage across the LED during operation when operating at a given current, wherein the voltage across the LED is within a voltage range, and wherein measuring the voltage across the LED comprises:
• monitoring the entire voltage range at a first resolution, and
• monitoring a sub-range at a second resolution higher than the first resolution;
• correlating, with the control unit, the LED voltage to a junction temperature of the LED such that the voltage is a proxy of the junction temperature;
• determining, with the control unit, fluctuations in the junction temperature of the LED in real-time based on the correlation;
• and
• controlling, with the control unit, operation of the LED based on the real-time determinations to compensate for fluctuations in photonic output of the LED due to changes in the junction temperature of the LED.

A diagnostic instrument comprising:

• a reaction vessel holding a fluid sample to be analyzed by an assay;
• a housing configured to receive the reaction vessel;
• an optical unit disposed at least partly within the housing, the optical unit comprising:
• an LED configured to provide an optical output for excitation of a prepared fluid sample within the reaction vessel;
• an optical detector configured to detect reactions in the prepared sample in response to optical excitation within an assay;
• and
• a control unit having a processor and a voltage sensor, the control unit configured to operate the LED to monitor performance of the assay, wherein the processor includes instructions recorded thereon configured for:
• monitoring a voltage across the LED during operation at a given current, wherein the voltage across the LED is within a voltage range, and wherein monitoring the voltage across the LED comprises:
• monitoring the entire voltage range at a first resolution, and
• monitoring a sub-range at a second resolution higher than the first resolution;
• correlating the voltage to a junction temperature of the LED such that the voltage is a proxy of the junction temperature;
• and
• determine a characteristic of the LED and/or photonic output based on the correlation.