Patent ID: 8310753

Claim:
A confocal scanning microscope comprising: an objective optical system that converges illumination light on a sample and forms a first image plane locating at a conjugate position with the sample; a scanning mechanism that scans a surface of the sample so as to obtain a light intensity signal from the sample; and a scanning optical system that is provided between the scanning mechanism and the first image plane formed by the objective optical system; the scanning optical system being composed of, in order from the scanning mechanism side, a first lens group having positive refractive power, a second lens group having negative refractive power, and a third lens group having positive refractive power, the third lens group having two chromatic aberration correction portions each formed by a positive lens and a negative lens or a negative lens and a positive lens adjoining each other, and when Vh is defined by the following expression: Vh= 1000×{( nh−nd )/( nd− 1)} where nd denotes a refractive index at d-line, and nh denotes a refractive index at h-line of an optical material constituting a lens, the following conditional expression being satisfied: V 31 >V 32 and V 33 <V 34 or V 31 <V 32 and V 33 >V 34 where V 31 denotes Vh value of the positive lens constituting a chromatic aberration correction portion being disposed to the scanning mechanism side among two chromatic aberration correction portions in the third lens group, V 32 denotes Vh value of the negative lens constituting the last mentioned chromatic aberration correction portion, V 33 denotes Vh value of the positive lens constituting a chromatic aberration correction portion being disposed to the objective optical system side, and V 34 denotes Vh value of the negative lens constituting the last mentioned chromatic aberration correction portion.