Optical filter system and fluorescence observation system

An optical filter system for fluorescence observation, wherein the filter system comprises an illumination light filter and an observation light filter;

• wherein the observation light filter has the following transmission characteristics in a wavelength range from 380 nm to 725 nm:
• at least two non-overlapping transmitting regions of the observation light filter, wherein each of the at least two transmitting regions of the observation light filter ranges from a first wavelength to a second wavelength being greater than the respective first wavelength, respectively, and has a mean transmittance greater than a first value within its range, respectively;
• and
• plural blocking regions of the observation light filter,
• wherein the plural blocking regions of the observation light filter include a first blocking region of the observation light filter, wherein the first blocking region of the observation light filter ranges from 380 nm to a smallest one of the first wavelengths of the at least two transmitting regions of the observation light filter and has a mean transmittance smaller than a second value within its range;
• and
• wherein the plural blocking regions of the observation light filter include at least one second blocking region of the observation light filter, wherein each of the at least one second blocking regions of the observation light filter adjoins two different transmitting regions of the at least two non-overlapping transmitting regions of the observation light filter, respectively, and has a mean transmittance smaller than a third value within its range, respectively;
• wherein the illumination light filter has the following transmission characteristics in the wavelength range from 380 nm to 725 nm:
• plural transmitting regions of the illumination light filter,
• wherein the plural transmitting regions of the illumination light filter include a first transmitting region of the illumination light filter, wherein the first transmitting region of the illumination light filter ranges from 380 nm to a wavelength smaller than the smallest one of the first wavelengths of the at least two transmitting regions of the observation light filter and has a mean transmittance greater than a fourth value within its range;
• and
• wherein the plural transmitting regions of the illumination light filter further include at least one second transmitting region of the illumination light filter, wherein each of the at least one second transmitting regions of the illumination light filter is a wavelength range within one of the at least one second blocking regions of the observation light filter, respectively, and has a mean transmittance greater than a fifth value within its range, respectively;
• and
• plural blocking regions of the illumination light filter,
• wherein each of the plural blocking regions of the illumination light filter is a wavelength range comprising one of the plural transmitting regions of the observation light filter and has a mean transmittance smaller than a sixth value within its range, respectively;
• wherein the first transmitting region of the illumination light filter contains a third transmitting region in a wavelength range between 440 nm and 560 nm having a width greater than 45 nm, wherein the third transmitting region has a mean transmittance less than 0.8;
• and
• wherein the mean transmittance of the first transmitting region is greater than the mean transmittance of the third transmitting region.