Patent ID: 11892706
Assignee: HITACHI HIGH-TECH CORPORATION
Field: Measurement (Instruments)
Classification: CPC G | IPC G

Claim 0:
1. An observation device that captures an image at a focal position inside a sample container that stores a sample liquid, the observation device comprising:
a holding part that holds the sample container;
an optical system that captures the image at the focal position; and
a computer that is coupled to the optical system and that controls the optical system,
wherein the optical system includes:
an objective lens disposed below the sample container;
an objective lens actuator that drives the objective lens in an optical axis direction;
a laser that irradiates the sample container with light;
a photodetector that detects a reflected light intensity of reflected light of the light;
a focus control unit coupled to the objective lens actuator that positions a focal point of the objective lens on a reflection surface imparting a peak in the reflected light intensity;
an incremental counter coupled to the focus control unit; and
a reflected light intensity determination unit coupled to the incremental counter, that determines, based on an intensity distribution of the reflected light, a position of the focal point;

wherein the computer determines, on a basis of the position of the focal point of the objective lens determined by the reflected light intensity determination unit, a driving direction of the objective lens actuator,
wherein the focus control unit drives the objective lens actuator to position the focal point on the reflection surface upon determining the peak is detected in the reflected light intensity,
wherein the incremental counter increments a count after the focus control unit has positioned the focal point on the reflection surface, and
wherein the computer:
determines, based on a count value of the count, whether the focal point is positioned at the focal position, and
causes the optical system to capture an image upon determining the focal point is positioned at the focal position and causes the focus control unit to drive the objective lens actuator upon determining the focal point is not positioned at the focal position.