Related LED lighting terms
Luminous flux (Luminous flux): refers to the radiant power that can be felt by the human eye, which is equal to the product of the radiant energy of a certain band per unit time and the relative viewing rate of the band. Luminous flux is usually expressed by Φ, and the unit is "lumen" (lm).
Illuminance: Indicates the luminous flux per unit area on the surface of the subject. It can be directly measured with an illuminance meter. The unit of illuminance is lux, which is the transliteration of English lux and can also be written as lx. For an object that is uniformly illuminated by light, when the luminous flux obtained on an area of 1 square meter is 1 lm, its illuminance is 1 lux.
Luminous intensity: Abbreviated as light intensity, the international unit is candela (Candela) abbreviated cd. Lcd refers to the luminous flux emitted by a light source within a unit solid angle in a specified direction. When the light source radiation is uniform, the light intensity is I=F/Ω, Ω is the solid angle, the unit is steradian (sr), F is the luminous flux, the unit is lumens, and for point light sources, I=F/4∏.
Luminance: refers to the brightness of a surface. Expressed by L, that is, the luminous flux reflected from a surface, and different objects have different reflection coefficients or absorption coefficients for light. The unit is candela/square meter (cd/m2).
Luminous efficacy: The ratio of the total luminous flux emitted by a light source to the electric power consumed by the light source is called the light efficiency of the light source. It is an important indicator to measure the energy saving of light sources. Unit: Lumens per watt (lm/w).
Color rendering index: The degree to which the light source presents the color of an object, that is, the degree of fidelity of the color, often called "color rendering index". The higher the color rendering index (0-100), the closer the color reproduction of the light source is to the natural primary color. Unit: Ra.
Color temperature: It is the most general indicator of the spectral quality of the light source. When the color of the light emitted by the light source is the same as that of the black body at a certain temperature, the temperature of the black body is called the color temperature of the light source. Unit: Kelvin (k).
The color temperature of commonly used light sources is: standard candlelight is 1930K; tungsten lamp is 2760-2900K; fluorescent lamp is 3000K; flash lamp is 3800K; noon sunlight is 5600K.
Beam angle (Beam angle): usually called angle, refers to the angle between two directions where the luminous intensity is equal to 50% of the maximum luminous intensity on a plane perpendicular to the center line of the beam.
Glare: There are objects with extremely high brightness or strong brightness contrast in the field of view, which can cause visual discomfort called glare. Glare is an important factor affecting the quality of the lighting.
Electromagnetic Interference (EMI): Electrical interference caused by electrical or electronic equipment. The interference level of high-frequency electronic equipment should comply with the Federal Communications Commission (FCC) or the International Electrotechnical Commission (IEC) regulations.
Lumens depreciation: During the use of the light source, with the delay of time, the phenomenon that its luminous flux gradually decreases is called luminous depreciation.
Power factor: The ratio of the power in W as the unit of the circuit to the root mean square product of voltage and current.
Lamp efficiency: refers to the ratio of the luminous flux value emitted by the lamp measured under specified conditions to the sum of the measured luminous flux values emitted by all light sources in the lamp.
Average life (Average life): Refers to the number of hours when a batch of bulbs to 50% of the number is damaged.
