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Home > Articles > English > LED knowledge > The difference between LED and LD

LED knowledge

The difference between LED and LD
From: The Site Author: LIGHTUP LED DateTime: 2013-7-6

LED and LD, although only one letter, but they are not the same types of products. Specific differences see below for reference.


1. What is LED?


LED is a Light Emitting Diode (LED) abbreviation. Widely seen in daily life, such as household appliances, lights, car tail fog and so on. The most notable feature of LED is long life, high photoelectric conversion efficiency. Under its original in some semiconductor materials on the PN junction, the injection of minority carrier and majority carrier recombination, when will the excess energy released in the form of light, which converts electrical energy directly into light energy. PN junction reverse voltage, minority carrier injection is difficult, it is not light. This use of injection electroluminescent diodes called the principle of making light-emitting diodes, commonly known as LED.


2. What is LD


LD is the abbreviation of the laser diode, laser diode physical architecture is placed between the light-emitting diode junction photoactive semiconductor layer having its rear end polished with partial reflection function, thus forming an optical cavity. In the case of a forward bias, LED junction emit light interacting with the optical cavity, thereby further encourage emitted from the junction of a single wavelength of light, such light on the physical properties of the material. Semiconductor laser diode operating principle, in theory, the same with gas lasers. Laser diode on the computer CD-ROM drive, laser printer print top small power photovoltaic devices have been widely used.


3. Both in theory, architecture, performance differences.


The difference in the working principle: LED is injected into the active region using carriers spontaneous radiative recombination, and the LD light by stimulated radiative recombination.


The difference in the structure: LD has an optical resonant cavity, so that the photons in the cavity oscillation zoom, LED no resonant cavity.


The difference in performance: LED no thresholds Feature, spectral density is several orders of magnitude higher than the LD, LED optical power export small divergence angle is large.


In summary, compared to the terms of the LD, LED has its own characteristics: Feature critical value does not exist, there is no noise pattern configuration, stable and without temperature control, long working life, high yield, the price is cheap.

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