Light source apparatus, microscopic device, optical detection device and optical detection method

A microscopic device, comprising a light source apparatus for optical detection and an objective lens disposed opposite to the light source apparatus with respect to a sample position, wherein the light source apparatus comprises:

• a first light source assembly configured to generate a first emergent light propagating in a first direction;
• a second light source assembly configured to generate a second emergent light propagating in a second direction, wherein the second direction and the first direction intersect with each other, one of the first emergent light and the second emergent light is a light for illumination, another one of the first emergent light and the second emergent light is a light for excitation, one of the first and second light source assemblies that is configured to generate the light for illumination is an illumination light source assembly, and another one of the first and second light source assemblies that is configured to generate the light for excitation is an excitation light source assembly, the light for illumination and the light for excitation are configured to be switched on at different time;
• a first dichroscope disposed at a location where the first direction intersects the second direction, and configured to make at least part of the first emergent light that is in a first band of wavelength transmit to continue propagating in the first direction, and to reflect at least part of the second emergent light that is in a second band of wavelength to propagate in the first direction, wherein the first band of wavelength and the second band of wavelength are different from each other;
• wherein the illumination light source assembly comprises:
• an illumination light source;
• and
• a diaphragm disposed between the illumination light source and the first dichroscope, and configured to block part of the light for illumination to form composite illumination combined with bright-field illumination and dark-field illumination simultaneously, wherein the diaphragm comprises a light shielding screen, one light-passing hole provided at a central location of the light shielding screen to form the bright-field illumination, and a plurality of light-passing holes or light-passing slits provided on the light shielding screen and distributed around the light-passing hole at the central location to form the dark-field illumination;
• wherein a distance R1 between an outer edge of the light-passing hole provided at the central location of the light shielding screen and a center of the diaphragm, a distance l between the diaphragm and the sample position, and a numerical aperture n of the objective lens satisfy following relationship:
• R1≤l·tg[arcsin(n)/3], and a distance R2 between an inner edge of the light-passing hole or light-passing slit distributed around the light-passing hole at the central location and the center of the diaphragm, the distance 1 between the diaphragm and the sample position, and the numerical aperture n of the objective lens satisfy following relationship:
• R2>l·tg[arcsin(n)].