Common Optical Terminology

- Apr 04, 2019-

1.Luminous flux

Luminous flux, (unit lumen Lm. Luminous flux, refers to the radiation power that the human eye can perceive, which is equal to the product of the radiant energy of a certain band per unit time and the relative visibility of the band. The relative visibility of light of different wavelengths is different, so when the radiation powers of different wavelengths are equal, the luminous fluxes are not equal.

2. Light intensity

The luminous flux (Im) emitted by the illuminant in a solid angle in a specific direction unit, in units of candela mcd. The international unit is a candela (candela) shorthand cd, other units have candlelight, branch light. 1cd or 1000mcd means that the light of a monochromatic light source (frequency 540X10ˇ12HZ, wavelength 0.550 micron) is emitted in a unit solid angle in a given direction (radiation intensity in this direction is (1/683) watt/sphericity). light intensity.

3. Illuminance

Luminosity refers to the degree to which an object is illuminated, expressed in terms of the luminous flux per unit area, expressed in lux (lx, lx), or lm/m2. 1 lux is equal to 1 lumen (lm), the luminous flux is evenly distributed over an area of 1 m2 of illuminance. Illuminance is based on the luminous flux received by the vertical plane.

4. Color temperature

A standard black body (e.g., iron) is heated, and when the temperature is raised to a certain degree, the color starts to change from red->light red-> orange-->white->blue-white->blue, using this The characteristics of light color change, when the light color of a light source is the same as the light color of a black body at a certain temperature, we refer to the absolute warmth of the black body as the color temperature of the light source, unit K

5. Wavelength

The change in color intensity of light can be described by data, which is called wavelength. The unit is nm. The wavelength of visible light ranges from 380 to 780 nm.

Red: 630-780nm Orange: 600-630nm Yellow: 570-600nm

Green: 500-570nm green: 470-500nm blue: 420-470nm

Purple: 380-420nm

6. Light effect

The ability of an electric light source to convert electrical energy into light, expressed in terms of luminous flux divided by power consumption, in lumens per watt (Lm/w).

7. Color rendering

The degree to which a light source is rendered for an object's color is called color rendering and is often referred to as the color rendering index (Ra). The degree to which the light source appears to the color of the object is called color rendering, that is, the degree of color fidelity. The light source with high color rendering has better color reproduction. The color we see is closer to the natural primary color, and the color rendering is low. The light source's reproduction of the color is poor, and the color deviation we see is also large.