Brief analysis of the thermal characteristics of LED lighting in practical applications (Photos)
introduction Each designer only has a clear understanding of the thermal characteristics of the LED from the PN junction to the environment to ensure a safe, reliable design and satisfactory performance. There may be multiple thermal interfaces such as bare chips or glue layers in the heat flow path, and their thickness and thermal resistance are difficult to control during production. In addition, the thermally conductive interface between the LED package and the luminaire housing as a heat sink further adds to the design challenge. The thermal resistance of the LED must be known as early as possible during the prototype phase. 1 current, color and performance The light output characteristics of an LED are primarily determined by its operating conditions. An increase in forward current causes the LED to generate more light. However, the current current remains constant and the light output decreases as the temperature of the LED increases. Figure 1 depicts the relationship between temperature, current, and light output. It also describes the offset of the LED-related color spectrum at the peak wavelength. For a single-color LED for general illumination, the peak of the blue spectrum shifts, thus changing the so-called color temperature of the LED. This has an impact on the senses within the LED lighting space. Figure 1 Current and temperature are dependent on the spectral intensity distribution in an LED light output Like many other products, lighting systems are designed to weigh cost and performance. The power distribution and the resulting heat dissipation requirements are largely determined by the energy conversion efficiency of the LED. It is defined as the ratio of the emitted light energy to the input electrical power. The energy efficiency value is closely related to the performance of another metric parameter. It is an evaluation index about usefulness, which is the ratio of the perceived light divided by the supplied electrical power. Performance is used to evaluate the pros and cons of different light sources. Unfortunately, the performance of LEDs will decrease as the junction temperature of the LED increases. Predicting the output luminous flux of an LED is the ultimate goal of lighting design. Thermal management solutions that provide effective heat dissipation produce more consistent color flux in LED applications. Heat is transferred from the LED package chip and the relevant data is provided by the supplier. A common heat conducting structure is shown in Figure 2. Approximately 50% of the junction-to-ambient thermal resistance of an LED lamp is caused by the LED package. Figure 2 Typical heat conduction structure of a power LED Bar Mat,Bar Floor Mats,Custom Bar Mat,Bar Table Mat Cixi Mingsheng Rubber & Plastic Co.,Ltd. , https://www.cixidoormats.com