A laser scanner, also known as a galvo laser, is composed of an X-Y optical scanner, an electronic drive amplifier, and an optical reflector. The signal provided by the computer controller drives the optical scanner through the drive amplifier circuit, thereby controlling the deflection of the laser beam in the X-Y plane. In a laser demonstration system, the waveform of optical scanning is a vector scan, and the system's scan speed determines the stability of the laser pattern.
When an initial position signal is input, the oscillating motor (laser galvo laser) swings a certain angle according to a certain voltage-to-angle conversion ratio. The entire process uses closed-loop feedback control, which is a common application of the five control circuits, including a position sensor, an error amplifier, a power amplifier, a position discriminator, and a current integrator. The principle of digital laser galvo laser is to convert analog signals into digital signals based on the principle of analog laser galvo laser. The scanning laser galvo laser is the core component of the marking machine, and the performance of the marking machine mainly depends on the performance of the scanning laser galvo laser.
The laser galvo head is composed of a stator, a rotor, and a detection sensor. The galvo laser is of the moving-coil type (the rotor is a coil), and the others are of the moving-magnet type (the rotor is a magnetic core). All galvo lasers use permanent magnets as the magnetic core, and the analog capacitive sensor is used as the detection sensor, while the digital galvo laser uses a grating ruler detection sensor. When the motor swings, the capacitance of the detection sensor changes slightly, and the change in capacitance is converted into an electrical signal, which is fed back to the controller for closed-loop control. The grating ruler sensor measures the actual deflection angle through the grating ruler and converts it into an electrical signal, which is fed back to the controller for closed-loop control. Since the rotor of a moving-coil-type galvo laser is a coil, the volume of the coil is relatively large, and the moment of inertia is large, which is not conducive to quick response. Therefore, it is not used nowadays. The moving-magnet-type galvo laser has a small volume and moment of inertia because the hollow cylindrical magnetic core is tightly fitted on the rotating shaft, so its fast response performance is very good.
The so-called galvo laser, also known as an ammeter, follows the design method of the ammeter. The mirror replaces the pointer, and the signal of the probe is replaced by a direct current signal controlled by the computer to complete the predetermined action.
Similar to the rotating-mirror scanning system, this typical control system uses a pair of folded mirrors, and the stepper motor driving this set of mirrors is replaced by a servo motor. In this control system, the use of a position sensor and the design idea of negative feedback circuit further ensure the accuracy of the system. The scan speed and repeat positioning accuracy of the entire system have reached a new level.