Lighting | small knowledge how the human eye is feeling light? - China lighting network

Human visual organs mainly by eyes, optic nerve, and related parts of the brain. The structure of the human eye as shown, eyes like a camera, it's the pupil like the iris of the camera, around the iris pupil aperture effect, it can adjust the size of the pupil, according to the strength of the light to control the amount of light entering the eye. The lens like the lens of the camera, it will be outside scenery focus imaging in the retina. Is in one of the sensitive photoreceptors in the retina, it will feel to convey information through the optic nerve to the brain's visual center, the formation of light and shade, color, shape, dynamic, far or near, such as visual perception, in order to get information of the outside world.

there are two kinds of photoreceptor cells of the retina, is opposite in the central part of the pupil distribution dense cones, in the central part is mainly around the rods. About 8 million cones, and there are three, respectively red, green and blue three areas in the spectrum of light reaction. About 1 and rods. 200 million, its high sensitivity, can feel faint light. In the bright light environment, brightness is more than a few CD/m2 ( Candela per square metre) , rod cells lose the activity, mainly plays a role of main photoreceptor cone cells, then the visual call photopic vision. Ming visual characteristics is to distinguish the color of the visual, and the objects on the discrimination ability of the details are accurate. Then the eyes of wavelength of 555 nm green light sensitivity is the highest. With wavelength decreases and gradually increase, the sensitivity were reduced gradually, until the end of the 380 nm and 780 nm, sensitivity to zero, which does not produce light. When in a very dark environment, brightness is less than a few percent CD/m2, cones lose activity, resume the function of light-sensitive rods, then visual call scotopic vision. Its characteristic is only can distinguish between light and shade, and no color feeling, and the ability to identify objects on the details of the greatly reduced. Scotopic vision to the wavelength of 507 nm radiation has the highest sensitivity. Between the above two situations, people in the dark and is not very dark, and as the vast 'twilight', the vision of people called the middle visual. The high brightness can also distinguish between colors, brightness is lower only light and shade. YanZhiXiang

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