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Cone (vision)
Cone cells, or cones, are photoreceptor cells in the retinas of vertebrate eyes including the human eye. They respond differently to light of different Visible spectrum, wavelengths, and the combination of their responses is responsible for color vision. Cones function best in relatively bright light, called the Photopic vision, photopic region, as opposed to rod cells, which work better in dim light, or the Scotopic vision, scotopic region. Cone cells are densely packed in the fovea centralis, a 0.3 mm diameter rod-free area with very thin, densely packed cones which quickly reduce in number towards the periphery of the retina. Conversely, they are absent from the optic disc, contributing to the Blind spot (vision), blind spot. There are about six to seven million cones in a human eye (vs ~92 million rods), with the highest concentration being towards the macula. Cones are less sensitive to light than the rod cells in the retina (which support vision at low light levels), ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Responsivity
Responsivity measures the input–output Gain (electronics), gain of a detector system. In the specific case of a photodetector, it measures the electrical output per optical input. A photodetector's responsivity is usually expressed in units of amperes or volts per watt of incident radiant flux, radiant power. For a system that responds linearly to its input, there is a unique responsivity. For nonlinear systems, the responsivity is the Derivative, local slope. Many common photodetectors respond linearly as a function of the incident power. Responsivity is a function of the wavelength of the incident Electromagnetic radiation, radiation and of the sensor's properties, such as the bandgap of the material of which the photodetector is made. One simple expression for the responsivity ''R'' of a photodetector in which an optical signal is converted into an electric current (known as a photocurrent) is R=\eta\frac\approx\eta\frac where \eta is the quantum efficiency (the conversi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
