The effect of LED infrared lamp
Infrared night vision, is in the night infrared camera attached to the LED infrared lights to emit the naked eye of the infrared light to illuminate the object, infra-red through the object reflected into the lens to imaging. The camera is infrared-sensing through the CCD, and the CDD is capable of sensing all the light, (visible light, infrared and ultraviolet rays, etc.), so in the absence of visible light, IR Lamp LED the infrared camera can be photographed to the naked eye, which is the role of LED infrared light.
LED infrared lamp, night vision monitoring LED infrared lamp is the abbreviation, is to cooperate with the surveillance camera, in the night to collect images of the light equipment. So, what is the principle of LED infrared light?
LED Infrared lamp According to its infrared light radiation mechanism is divided into semiconductor solid luminescent (infrared emission Two-level tube) LED infrared lamp and thermal radiation led infrared lamp two kinds. The principle and characteristics of our introduction are as follows:
Principle and characteristics of LED infrared lamp
The luminous body is composed of the infrared emitting two-stage tube matrix. The infrared emitting two-stage tube is made of a PN junction by a material with high infrared radiation efficiency (gallium arsenide GaAs), and an infrared ray excited by positive bias to the PN junction. The spectral power distribution is the center wavelength 830~950nm, the half peak bandwidth is about 40nm, it is narrow-band distribution, IR Lamp LED and can be sensed by the ordinary CCD black and white camera. Its greatest advantage is that it can be completely free of red, (using 940~950nm wavelength infrared tubes) or only faint red bursts (red bursts are visible) and long life.
The emissivity of the Infrared light-emitting diode (ΜW/M2) is expressed by the irradiance degree. Generally speaking, the infrared radiation power is proportional to the positive working current, but the temperature of the device rises due to the heat consumption of the current when the maximum nominal value is close to the positive current, which decreases the light emission power. IR Lamp LED The infrared diode current is too small, will affect its radiate power to play, but the working current over general affects its life, even causes the infrared diode to burn.
When the voltage crosses the forward threshold voltage (about 0.8V) The current begins to flow, and is a very steep curve, indicating that its working current is sensitive to the operating voltage. Therefore, the work voltage is accurate and stable, otherwise it will affect the performance and reliability of the radiated power. Radiation power decreases as the ambient temperature increases, IR Lamp LED including the ambient temperature generated by its own heating. LED infrared lamp, especially the long distance led infrared light, heat consumption is the design and selection should pay attention to the problem.
The maximum radiation intensity of the IR diode is generally in front of the optical axis and decreases with the increase of the angle between the radiation direction and the optical axis. IR Lamp LED The angle of 50% of the maximum radiation intensity is called the half intensity radiation angle. The radiation angle of the infrared light-emitting diode with different package process models is different.
The principle of LED infrared lamp
(i) Infrared light-emitting diode (LED) principle led infrared light emitting body is composed of infrared light-emitting diode (LED) matrix. The infrared light-emitting diode is made of PN Junction by the material with high infrared radiation efficiency, and the positive bias pressure is injected into the PN Junction to excite the infrared light. The spectral power distribution is the central wavelength $number-950nm, the half peak bandwidth is about 40nm, as shown in Fig. 1 (850nm, 940nm infrared light-emitting diode spectrum distribution map). IR Lamp LED It is a narrow-band distribution, which can be felt by the ordinary CCD black and white camera. Its greatest advantage is that it can be completely free of red, (using a 940~950nm wavelength infrared tube) or only a faint red storm (850nm wavelength infrared tube), but also has a long life characteristics.
(ii) light-controlled soft switching circuit the LED infrared lamp adopts a light controlled soft switching circuit to reduce the impact of its working state conversion and prolong the service life of the LED infrared lamp.
(three) constant-current voltage regulator to compensate for the difference of light radiation power of LED infrared lamp in winter and Xia Dihong, the LED infrared lamp adopts a constant current circuit, IR Lamp LED which makes the infrared light-emitting diode light power stable, thus enhances the use of LED infrared lamp and prolongs the service life.
(d) led infrared lamp selection and the use of LED infrared lamp selection The most important problem is led infrared light and camera, lens, protective cover, power supply, IR Lamp LED such as complete sets. Some people bought the surveillance cameras, lenses, shields, power, and even after the installation to consider the purchase of LED infrared lights, this is not correct, should be in the design of all equipment considerations, it is considered an infrared low illumination night vision monitoring systems engineering to carry out the design.