The conventional infrared LED lamp bead is similar to the general visible LED lamp bead in appearance, but it emits infrared light. The voltage is generally about 1.4V, and the working current is generally less than 20mA. In order to adapt to different working voltage, the finite current resistor is often connected in series in the loop.
When the infrared LED lamp bead is used to control the corresponding controlled device, the control distance is proportional to the emission power. In order to increase the infrared emission tube working in the pulse state, because the effective transmission distance of the pulse light is proportional to the wind-induced current of the pulse, the emission distance of the infrared light can be increased only by increasing the peak IP as much as possible. The method to improve IP is to reduce the pulse duty ratio, that is, to compress the pulse width T, and to reduce the pulse duty ratio can also greatly increase the emission distance of low-power infrared light-emitting diodes. The power of ordinary infrared light-emitting diodes can be divided into three categories: low power, medium power and high power. In order to produce modulation light, only a pulse voltage of a certain frequency is added to the driving tube.
When the infrared light emitting diode emits infrared to control the controlled device, there are corresponding infrared photoelectric conversion elements in the controlled device, such as infrared receiving diode, infrared receiving head, photosensitive triode, etc.
There are two ways to transmit and receive infrared rays: direct and reflection. The direct light-emitting tube and the receiving tube are relatively placed at the two ends of the emission and the controlled object, with a certain distance between them; the reflective light-emitting tube and the receiving tube are in parallel, usually the receiving tube is always without light, only when the infrared light emitted by the light-emitting tube meets the reflector, the receiving tube receives the reflected infrared light to work. Double tube infrared emission circuit can improve the emission power and increase the working distance of infrared emission.According to the characteristics of infrared LED lamp beads, it can be widely used according to different wavelengths:
1. Wavelength: 808nm, suitable for medical devices, space optical communication, infrared lighting, solid laser pump light source;
2. Wavelength: 830nm, suitable for the automatic card swiping system of high-speed road (night vision system is the best, you can see a little red light on the tube core, the effect is better than 850nm);
3. Wavelength: 840nm, suitable for camera, color zoom infrared waterproof;
4. Wavelength: 850nm, suitable for camera, digital photography, monitoring, apartment intercom, anti-theft alarm, infrared waterproof;
5. Wavelength: 870nm, suitable for cameras in shopping malls and intersections;
6. Wavelength: 940nm, suitable for remote control, such as remote control of household appliances.