Principles and characteristics of uv curing lampread count [271] release time：2020-01-01 19:09:00
uv curing lamp While its application is becoming more and more widespread, its working principle and characteristics are believed to be also used by many traditional and UV led The first consideration for manufacturers who are hesitant about time. At the same time, manufacturers who are in the process of transformation may not necessarily know the working principle of UV curing lamps. Let’s learn more about it together.
1、uv The luminescence mechanism of the curing lamp: The luminescence of the uv curing lamp is actually the way of PN junction luminescence. What is it specifically? The terminal voltage of the PN junction forms a certain potential barrier. When a positive bias voltage is applied, most carriers in the P region and N region will diffuse into each other (this is learned in university physics). Since the electron mobility is much greater than the hole mobility, a large number of electrons will be distributed to the P region, which will form a small amount of carrier injection in the P region. These electrons combine with holes in the valence band and the energy produced is released in the form of light energy. This is how a PN junction emits light.
2、Characteristics of uv glue curing lamp: current controller, the load characteristic of the UI curve is similar to that of the PN junction. A small change in the small voltage can cause a large change in the forward current (indicator level). The reverse leakage current is very small, which is the reverse breakdown voltage. In actual use, it should be selected. UVLED Forward voltage decreases with temperature and has a negative temperature coefficient. UVLED consumes power and partially converts it into light energy, which is what we need. The rest is converted into heat, raising the temperature. The heat dissipated can be expressed as .
3、UVLED luminous efficiency: usually called the external quantum efficiency of the component, which is the product of the internal quantum efficiency of the component and the extraction efficiency of the component. The so-called internal quantum efficiency of a component is actually the electro-optical conversion efficiency of the component itself, which is mainly related to the characteristics of the component itself (such as component material bands, defects and impurities), base composition and crystal structure of components, etc. The extraction efficiency of a component refers to the number of photons generated within the component, which can be measured outside the component after absorption, refraction and reflection by the component itself. Therefore, factors for extraction efficiency include the absorption of the component material itself, the geometric structure of the component, the difference in refractive index between the component and the packaging material, and the scattering properties of the component structure. The product of the internal quantum efficiency of the component and the extraction efficiency of the component is the luminous effect of the entire component, which is the external quantum efficiency of the component. The focus of early component development is to improve its internal quantum efficiency. Improving the blocking rate is the main means of changing the crystal quality and crystal structure, that is, it is not easy to convert electrical energy into thermal energy, thereby indirectly improving the luminous efficiency of UV LEDs, so that an internal quantum efficiency of 70% can be obtained. However, the theory of internal quantum efficiency is almost close to the theoretical limit. In this case, it is impossible to increase the total amount of light by improving the internal quantum efficiency of the element, so improving the extraction efficiency of the element becomes an important research topic. The current methods are mainly: changes in grain shape, TIP structure, and surface roughening technology.
4、The heat dissipation characteristics of uv glue curing lamp: the current is small and the LED temperature rise is not obvious. If the ambient temperature is high, the dominant wavelength will be red-shifted, the brightness will be reduced, and the uniformity and uniformity will be reduced. In particular, the temperature rise of large display screens has a greater impact on the reliability and stability of LEDs. So cooling design is key. 5、UVLED Optical properties: UVLED provides a half-maximum full-width monochromatic light. Since the semiconductor energy gap decreases with the increase of temperature, its luminescence peak wavelength increases with the increase of temperature, that is, the spectrum is red-shifted, and the temperature coefficient is +2~3/. UVLED brightness L and forward current. The current increases and the brightness increases approximately. In addition, brightness is also related to ambient temperature. When the ambient temperature is high, the recombination efficiency decreases and the luminous intensity decreases.
6、High power: mainly consider heat dissipation and light emission. In terms of heat dissipation, copper-based thermal pads are used to connect aluminum-based heat sinks, which can be connected by soldering between the die and the thermal liner. The UV glue curing lamp is a very good heat dissipation method.
7、UVLED lifespan: Long working time can lead to aging, especially for high power, the problem of light decay is more serious. When measuring the service life, the degree of damage to the lamp tube at the end of the UVLED life is not enough. The life of the UVLED LED should be specified by the light attenuation percentage, such as 35%, which is more meaningful.
