a lighting module;

an imaging module; and

an objective lens;

wherein the lighting module is configured for outputting excitation light to excite the sample to generate excited light, the imaging module comprises a time delay integration line scan camera, the time delay integration line scan camera is configured to record the excited light, the objective lens is a channel configured for outputting the excitation light and collect the excited light;

the objective lens comprises a first group of lenses, a second group of lenses, a third group of lenses, a fourth group of lenses, a fifth group of lenses, a sixth group of lenses, and a seventh group of lenses which are arranged from an object side to an image side in said sequence, the first group of lenses to the third group of lenses bear a negative power, and the fourth group of lenses to the seventh group of lenses bear a positive power;

the first group of lenses meets: 9.2<f1/fobj<9.7; the second group of lenses meets: 4.7<f2/fobj<5.5; the third group of lenses meets: 4.6<f3/fobj<5.6; the fourth group of lenses meets: 3.25<f4/fobj<3.88; the fifth group of lenses meets: 5.71<f5/fobj<6.11; the sixth group of lenses meets: −4.76<f6/fobj<−3; the seventh group of lenses meets: −23.9<f7/fobj<−19.5; wherein, f1 is a focal length of the first group of lenses, f2 is a focal length of the second group of lenses, f3 is a focal length of the third group of lenses, f4 is a focal length of the fourth group of lenses, f5 is a focal length of the fifth group of lenses, f6 is a focal length of the sixth group of lenses, f7 is a focal length of the seventh group of lenses, and fobj is a focal length of the objective lens.