Research About The Measurement Of The Laser Power With Hundred Watt Level

With the vigorous development of laser processing technology, requirement on the quality of laser in industrial production is also rising. In all the parameters of the laser, the laser power is an important parameter which determines it’s application field. In laser processing, especially the processing for a long time, the attenuation seriously affect the quality and efficiency of the products. Therefore, if we can monitor the laser power in laser processing has an important value to improve the quality of the products. Based on this, the paper designed a set of high sensitivity of thermoelectric laser power measurement system by using a wide range of temperature detection technology. In this system, the main research contents including the following aspects.Firstly, this paper introduces some measurements of laser power which commonly used at home and abroad, and based on this designing a set of laser power measurement system. The system uses the radiation characteristics and laser conversion effect, determined the measurement scheme of laser power by analyzing the intrinsic relationship between the energy, power and temperature.Secondly, the overall scheme of the measurement system is expounds. Launched laser power by the temperature signal which transformed from the laser by the laser detection sensor and collected by the circuit and STM32. Based on this, the physical model and mathematical model of the measurement system is established, also the laser detection sensor which is the core module of the measurement system is designed.Thirdly, a wide range temperature measurement method which based on the thermistor is designed according to the measuring principle of the system. This method measured the thermistor by using the mathematical relationship between the charge and discharge time which produced by the RC circuit and the thermal resistance, and then obtained the temperature value which we need through the relationship between the thermal resistance and the temperature. According to this, the circuit of the measurement is designed, which included the RC circuit, comparison circuit and the second charge and discharge circuit that meeting the initial charge and discharge conditions. And realized the square wave input of the circuit, the acquisition of the charge and discharge time and the control of the secondary charge and discharge through the STM32.Finally, debugging and experimental verification of the measurement, and proposing a method to get the power based on the curve fitting through the analysis of the temperature curve which comes from the different laser power. Indicated the feasibility of laser power measurement designed in this paper by comparing experimental with the standard power meter.