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

Claim 0:
1. An absorbance detector for a chromatograph comprising:
a light source;
a flow cell that receives light generated by the light source;
a photodetector that detects light transmitted through the flow cell;
a light shield member that is rotatably arranged in a light path from the light source to the flow cell and shields at least part of the light in the light path;
a motor that rotates the light shield member to change the light shield member between a light-shielding state where the light shield member shields 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;
a reference position detector that rotates the motor to rotate the light shield member from an arbitrary initial position in a rotation direction, and also acquires a change in amount of light received by the photodetector 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 a reference position of the light shield member in the rotation direction of the light shield member based on the acquired change in the amount of the received light during a reference position detection operation before a normal operation of detecting absorbance of a sample; and
a normal operation controller that controls a rotation position of the motor based on the reference position detected by the reference position detector 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.