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Spectral sensitivity of the human eye

The human eye is only able to perceive a small part of electromagnetic radiation . At normal light intensity, the retina is sensitive to radiation with a wavelength from 380 nm to 760 nm (the visible light region of the electromagnetic spectrum). This region also overlaps with one of the permeability bands of the Earth's atmosphere. Another reason why the human eye perceives the most in this area is the fact that it corresponds to the maximum spectral radiation of the Sun. From the graph of the spectral sensitivity of the human eye, we can see that the human eye is also sensitive to red light with a wavelength of, for example, 660 nm. However, in order to achieve a visual perception of the same intensity as for the radiation of light with a wavelength of 550 nm, the luminous flux must befrom the same area 10,000 times larger.

Spectral sensitivity of cones

Light-sensitive cells of the human eye

There are about 6 million cones in the human retina . There are three functional types, containing different types of photopsin. Each of them has a somewhat different iodopsin (specialization in green, blue and red). Suppositories need quite a lot of light to work , but on the other hand, they provide more precise vision than rods.

Quantities important to determine the spectral sensitivity of the eye

If electromagnetic radiation emanates from a certain source, then E(t)/S is called radiant flux Φe , unit − Watt ( W ). The performance of radiant energy, evaluated according to the magnitude of the light sensation it causes, is called the luminous flux Φ , unit − lumen ( lm ). We call Φ/Φe the luminous efficiency of the radiation . The normalized function of the luminous efficiency for different wavelengths is called the relative luminous efficiency of radiation , 3 examples of which can be seen in the graph above. The maximum light efficiency is 680 lm/W . In other words: monochromatic radiation with a wavelength of 550 nm at a power of 1 W is equal to a luminous flux of 680 lm.

Links

Related Articles

• Photosensitive cells and their functions
• Adaptation of the eye to light intensity

External links

• [Spectral sensitivity (Encyclopedia of Physics)]

References

JUNQUEIRA, Luiz Carlos Uchoa and José CARNEIRO. Basic histology : text & atlas. 11th edition. New York : McGraw-Hill, c2005. ISBN 0071440917 .

Resources

• VLADIMIR, Sacek. telescope-optics.net : Eye spectral response [online]. ©2006. Last revision March-June 2015, [cit. 2012-12-28]. < https://www.telescope-optics.net/eye_spectral_response.htm >.

• PRAMACOM-HT, spol. s ro  infrared.cz : Spectral sensitivity of the human eye [online]. [feeling. 2012-12-28]. < http://www.infrared.cz/domains/infrared.cz/cz/ >.