Concentration measuring method

A concentration measuring method for optically measuring a concentration of a predetermined chemical component in an object to be measured, the method comprising the steps of:

• irradiating at least light having a first wavelength that has an absorbability with respect to the chemical component, and light having a second wavelength that has no or substantially no absorbability with respect to the chemical component, or an absorbability that is relatively lower than that of the light having the first wavelength, from a single light-emitting unit toward the object to be measured using a time-sharing method;
• sequentially receiving the light that is produced by the irradiation and passes through the object to be measured in a time-sharing manner by a single light-receiving unit;
• inputting a first light-receiving signal based on the light having the first wavelength and a second light-receiving signal based on the light having the second wavelength, each produced by the received light, into differential signal forming unit;
• deriving the concentration of the predetermined chemical component from a measured value based on an output signal output from the differential signal forming unit in accordance with the input, and data stored in storage unit in advance;
• and
• controlling a light emission amount of the light-emitting unit on the basis of a feedback signal corresponding to the differential signal.

A concentration measuring method, comprising the steps of:

• irradiating at least light having a first wavelength and light having a second wavelength, each having a different light absorptivity with respect to an object to be measured, onto the object to be measured using a time-sharing method;
• sequentially receiving the light of each wavelength that optically passes through the object to be measured as a result of the irradiation of the light of each wavelength, using a common light-receiving sensor;
• forming a differential signal between a signal related to the light having the first wavelength and a signal related to the light having the second wavelength output from the light-receiving sensor in accordance with the received light;
• deriving a concentration of a chemical component in the object to be measured on the basis of the differential signal;
• and
• controlling the amount of light during the emission of at least one of the light having the first wavelength and the light having the second wavelength on the basis of a feedback signal corresponding to the differential signal.

A concentration measuring method, comprising the steps of:

• irradiating at least a first light and a second light, each having a different light absorptivity with respect to an object to be measured, onto the object to be measured using a time-sharing method;
• receiving each light that optically passes through the object to be measured by irradiation of each light onto the object to be measured, using a common light-receiving sensor;
• forming a differential signal on the basis of a signal related to the first light and a signal related to the second light output from the light-receiving sensor in accordance with the received light;
• deriving a concentration of a predetermined chemical component in the object to be measured on the basis of the differential signal;
• and
• controlling the amount of light during the emission of at least one of the light having the first wavelength and the light having the second wavelength on the basis of a feedback signal corresponding to the differential signal.

A concentration measuring method, comprising the steps of:

• irradiating at least light having a first wavelength and light having a second wavelength, each having a different light absorptivity with respect to an object to be measured, onto the object to be measured using a time-sharing method;
• receiving the light of each wavelength that optically passes through the object to be measured as a result of the irradiation of the light of each wavelength, using a common light-receiving sensor;
• forming a differential signal between a signal related to the light having the first wavelength and a signal related to the light having the second wavelength output from the light-receiving sensor in accordance with the received light;
• deriving a concentration of a chemical component in the object to be measured on the basis of the differential signal;
• and
• controlling the amount of light during the emission of at least one of the light having the first wavelength and the light having the second wavelength on the basis of a feedback signal corresponding to the differential signal.

A concentration measuring method, comprising the steps of:

• irradiating at least a first light and a second light, each having a different light absorptivity with respect to an object to be measured, onto the object to be measured using a time-sharing method;
• receiving each light that optically passes through the object to be measured by irradiation of each light onto the object to be measured, using a common light-receiving sensor;
• forming a differential signal on the basis of a signal related to the first light and a signal related to the second light output from the light-receiving sensor in accordance with the received light;
• deriving a concentration of a predetermined chemical component in the object to be measured on the basis of the differential signal;
• and
• controlling the amount of light during the emission of at least one of the light having the first wavelength and the light having the second wavelength on the basis of a feedback signal corresponding to the differential signal.