In the 19th century, mankind entered the era of electrical lighting. After development, it is now the era of the fourth generation of solid-state light sources-LED lighting. Let's learn about LED lighting.
Glossary: LED is the acronym for Light Emitting Diode, the full Chinese name is "Light Emitting Diode".
Based on the different semiconductor materials used, the color of light-emitting diodes is also different. The traditional ones are red, green, orange, yellow, blue and so on. So it will be called blue LED or something. White light is composite light, so the so-called white light LED is modulated on the above basis.
Basic parameters of lighting application:
Luminous flux
refers to the radiant power that the human eye can feel, that is, the ratio of bright light emitted by the light source. The unit is LW (lumens). The nominal luminous flux of a 40W ordinary incandescent lamp is 360lm, the nominal luminous flux of a 40W daylight fluorescent lamp is 2100 lm, and the luminous flux of a 400 W standard high pressure sodium lamp can reach 48000 lm.
Luminous efficiency
The ratio of luminous flux to electric power, the unit is generally lm/W. Luminous efficiency represents the energy-saving characteristics of the light source, which is an important indicator to measure the performance of modern light sources.
Luminous intensity and light intensity distribution
The luminous intensity of an LED is a characterization of its luminous intensity in a certain direction. Since the luminous intensity of LEDs vary greatly in different spatial angles, we need to understand the luminous intensity distribution characteristics of the LED. This parameter is of great practical significance and directly affects the minimum viewing angle of the LED display device.
Wavelength
Regarding the spectral characteristics of the LED, we mainly look at whether its monochromaticity is good, and we must pay attention to whether the main colors of red, yellow, blue, green, and white LEDs are pure. Because in many occasions, such as traffic signal lights, the color requirements are more stringent. However, it is observed that some of the LED signal lights in our country are blue in green and deep red in red. From this phenomenon, we have conducted special research on the spectral characteristics of LEDs. Very necessary and very meaningful.
