Research On Self-mixing Interference Sensing Measurement Technology Based On Laser Mouse

When a portion of light emitted from a laser source is reflected or scattered back into the laser cavity by an external target,the reflected light will mix with the light inside the cavity,causing a modulation of the laser output power.This phenomenon is called as self-mixing effect,in which the reflected light carries some information of the external target.The self-mixing effect comes from the optical feedback effect.People always tried to eliminate the optical feedback effect previously.Gradually,people began to use it to measure some physical quantities,thus self-mixing interference technology was brought forth.For laser self-mixing system has many advantages,such as simple structure,easy alignment,non-contact.It has been used in more and more applications,especially the vibration measurement,displacement,speed and other physical quantities.Many measurement systems can provide high precision,but they require many optical components,lead to high cost,complex and big volume.In fact,not all situations require such high precision;an integrated and inexpensive tool is required in many practical occasions.In this case,an integrated and cost-effective interferometric sensor is essential for displacement measurement.In recent years,the mouse has become a part of everyday life.After technical innovation in these years,the accuracy of the mouse is higher,besides,benefit from mass production,the price of mouse is cheap.The mouse acted as measuring tool has been applied in the field of some low cost measurement.In this paper,a laser mouse with the self-mixing principle is applied to measurement;this system can be applied in wide range displacement measurement and low frequency vibration measurement.In Linux system,we design the key code and define some macros used in the experimental measurement.In the displacement measurement,we design the structure of the system,including the mouse chip selection,a circuit to servo motor protection and a program,the displacement measurement experiment was carried out with some different speeds,and the results show that the system can provide the accuracy of 0.1%.In the vibration measurement at low frequency,we design the structure of the system,including the fixed frame,contrast light path and a program.After measurement under different frequency,the results show that the system can meet the demand of the general vibration measurement,and the system is stability.Proved by the experiment,the mouse sensor system can be applied to a wide range of displacement measurement with low frequency vibration measurement;the experimental results show that the system meets the general requirements.The system has a broad application prospect for its non-contact measurement,stable operation,low cost.