Automatic analyzer

An automatic analyzer comprising:

• a light source configured to emit light;
• a spectroscope configured to disperse light, which is emitted by the light source and is transmitted through a liquid mixture of a sample and a reagent, into different wavelengths;
• a photo detector including a plurality of photo detectors which receive light from the spectroscope, each of the photo detectors configured to receive light related to a wavelength band corresponding to a location of that photo detector, and to generate a signal according to the received light, the plurality of photo detectors being two-dimensionally laid out along a channel direction parallel to a diffusion direction of wavelengths of light from the spectroscope and a column direction orthogonal to the channel direction;
• a memory configured to store a plurality of photo detector identifiers related to the plurality of photo detectors and a plurality of wavelength band identifiers in association with each other and to associate wavelength band identifiers related to a same wavelength band with photo detectors belonging to a same channel among the plurality of photo detectors;
• a selector configured to select a specific plurality of specific photo detectors from the photo detectors, the specific plurality of photo detectors corresponding according to a specific photo detector identifier associated with a wavelength band identifier of a measurement wavelength band corresponding according to a measurement item of the sample;
• a calculation processor configured to calculate an absorbance related to the measurement item based on a signal from a selected specific photo detector,
• wherein the calculation processor generates a weighted-sum signal obtained by weighting and adding, across a specific plurality of channels corresponding to the specific plurality of photodetectors, signal strengths of the specific plurality of photo detectors based on photo detection sensitivities corresponding to channel positions of the specific plurality of channels with respect to the measurement wavelength band of the plurality of specific photo detectors, and calculates the absorbance based on the generated weighted-sum signal,
• wherein when a plurality of electrical signals from the specific plurality of photo detectors for the specific plurality of channels N are used in absorbance calculations for the sample, the calculation processor generates the weighted-sum signal by weighting and adding the signal strengths of the photo detectors included in the specific photo detector based on the photo detection sensitivities corresponding to channel positions with respect to the measurement wavelength band of the photo detectors and absorption spectrum information of a measurement item, and calculates the absorbance based on the generated weighted-sum signal Abs according to the following equation:
• Abs
• =
• ∑
• n
• N
• ⁢
• a
• n
• ·
• X
• n
• where Xn is a strength of an electrical signal of a channel n, and an is a weighting coefficient which corresponds to a photo detection sensitivity coefficient with respect to a predetermined wavelength band to the electrical signal of the channel n, and
• wherein weighting coefficients are set to a larger value with increasing photo detection sensitivity with respect to the predetermined wavelength band and a smaller value with decreasing photo detection sensitivity with respect to the predetermined wavelength band.