What is photopic luminance?
What is photopic luminance?
Photopic vision is the vision of the eye under well-lit conditions (luminance levels from 10 to 108 cd/m2). In humans and many other animals, photopic vision allows color perception, mediated by cone cells, and a significantly higher visual acuity and temporal resolution than available with scotopic vision.
What is luminous sensitivity?
Cathode type. Cathode luminous sensitivity is the photoelectric current from the photocathode per incident light flux (10-5 to 10-2 lumens) from a tungsten filament lamp operated at a distribution temperature of 2856K.
What is luminous efficacy formula?
The equation will be efficacy = luminous flux / power. The SI unit for the result will be lm/W. Gather the information about the wattage and luminous flux for the light source you wish to analyze.
What is Mesopic and photopic?
Photopic vision facilitates excellent color perception, whereas colors are barely perceptible under scotopic vision. Mesopic vision falls between these two extremes. In most nighttime environments, enough ambient light prevents true scotopic vision.
What is the luminous efficacy of LED?
Examples
| Category | Type | Overall luminous efficacy (lm/W) |
|---|---|---|
| Light-emitting diode | LED screw base lamp (120 V) | 102 |
| 5–16 W LED screw base lamp (230 V) | 75–210 | |
| 21.5 W LED retrofit for T8 fluorescent tube (230 V) | 172 | |
| Theoretical limit for a white LED with phosphorescence color mixing | 260–300 |
What is luminous efficiency?
Definition of luminous efficiency : the ratio of the total luminous flux radiated by any source to the total radiant flux from that source commonly expressed in lumens per watt.
What is luminous efficiency explain?
Luminous efficacy is a measure of how well a light source produces visible light. It is the ratio of luminous flux to power. Depending on the context, the power can be either the radiant flux of the source’s output, or the total electric power consumed by the source. Lamps convert electrical energy into light.
What is mesopic condition?
Mesopic vision is a combination of photopic vision and scotopic vision in low but not quite dark lighting situations. Mesopic light levels range from luminances of approximately 0.01 cd/m2 to 3 cd/m2. Most nighttime outdoor and street lighting scenarios are in the mesopic range.
