| 摘要 |
PROBLEM TO BE SOLVED: To enable a marker bead to be read with a less influence due to a focus deviation and with high accuracy even when a protective layer is formed to be thick.SOLUTION: A pickup part 12 comprises: a laser oscillator 126 that emits laser light; an objective lens 121 that is set so as to cause the laser light to be converged on a bio-disc 100, and cause the spot shape in which the laser light is converged to be formed into an elliptical shape having a major axis in a direction parallel with a track direction of the bio-disc on a reflective layer 102 and to be formed into the elliptical shape having the major axis in a direction orthogonal to the track direction at a marker bead reading position anchored onto a protective layer 103; a light reception part 130 that receives reflection light of the laser light converged on the bio-disc 100. A marker bead detection part 25 counts up the quantity of marker beads 200 where a biological specimen anchored on the protective layer 103 of the bio-disc 100 is bound on the basis of a signal from the light reception part. |
