Patent ID: 11933772
Assignee: SHIMADZU CORPORATION
Field: Measurement (Instruments)
Classification: CPC G | IPC G

Claim 6:
7. A reference position detection method of detecting a reference position of a light shield member that is rotatably arranged in a light path from a light source to a flow cell in an absorbance detector and shields at least part of light in the light path, comprising the steps of:
generating the light by the light source in the absorbance detector;
rotating the light shield member from an arbitrary initial position in a rotation direction by a motor to change the light shield member between a light-shielding state where the light shield member shields the at least part of the light generated from the light source to the flow cell and a non-light-shielding state where the light shield member does not shield the light generated from the light source to the flow cell during a reference position detection operation before a normal operation of detecting absorbance of a sample;
detecting light transmitted through the flow cell by a photodetector during the rotation of the light shield member during the reference position detection operation;
acquiring a change in amount of light received by the photodetector due to the rotation of the light shield member to detect a rotation position of the light shield member when the light shield member is at a predetermined certain angle to the light path, the rotation position of the light shield member being a relative rotation position with respect to the initial position, as the reference position in the rotation direction of the light shield member based on the acquired change in the amount of the received light during the reference position detection operation; and
controlling a rotation position of the motor based on the detected reference position in a state where the sample flows into the flow cell to change the light shield member between the light-shielding state and the non-light-shielding state during the normal operation.