Why is the intensity profile of fluorescent light really different from the other examples? Are the any special features that other light sources do not have?
rohta
I think it has to do with energy conservation? He talked about it a bit last lecture if I remember correctly.
allai5
@SnackMixer Not sure about the other types of light, but I think this may be due to the small amounts of mercury in fluorescent light tubes. For cold cathode and hot cathode fluorescent lights, the electric current inside the discharge tube vaporizes the mercury in order to produce the UV light that excites the phosphor. Mercury has spectral lines at yellow, green, cyan and blue, which is shown in the diagram above.
Parker
I recall that as well rohta. Think he spoke about how that makes fluorescent feel so wonky and unnatural to us, because it's really a poor substitute for daylight.
ilovecg
I am a little confused about SPD and spectral irradiance. Because according to Wikipedia, a spectral power distribution (SPD) measurement describes the power per unit area per unit wavelength of an illumination (radiant existence), while spectral irradiance is the irradiance of a surface per unit frequency or wavelength.
JCDenton
Yeah, me too. Is the Wikipedia definition not quite right in this case?
Why is the intensity profile of fluorescent light really different from the other examples? Are the any special features that other light sources do not have?
I think it has to do with energy conservation? He talked about it a bit last lecture if I remember correctly.
@SnackMixer Not sure about the other types of light, but I think this may be due to the small amounts of mercury in fluorescent light tubes. For cold cathode and hot cathode fluorescent lights, the electric current inside the discharge tube vaporizes the mercury in order to produce the UV light that excites the phosphor. Mercury has spectral lines at yellow, green, cyan and blue, which is shown in the diagram above.
I recall that as well rohta. Think he spoke about how that makes fluorescent feel so wonky and unnatural to us, because it's really a poor substitute for daylight.
I am a little confused about SPD and spectral irradiance. Because according to Wikipedia, a spectral power distribution (SPD) measurement describes the power per unit area per unit wavelength of an illumination (radiant existence), while spectral irradiance is the irradiance of a surface per unit frequency or wavelength.
Yeah, me too. Is the Wikipedia definition not quite right in this case?