Title :
Optical micro encoder using a twin-beam VCSEL with integrated microlenses
Author :
Miyajima, Hiroshi ; Yamamoto, Eiji ; Yanagisawa, Kazuhisa
Author_Institution :
Olympus Opt. Co. Ltd., Tokyo, Japan
Abstract :
An improved optical micro encoder using a vertical-cavity surface-emitting laser (VCSEL) is presented in this paper. A twin-beam VCSEL is used to obtain two quasi-sinusoidal signals in phase quadrature, thereby both detection of the displacement direction and signal interpolation have become possible. Also, microlenses monolithically integrated onto the VCSEL improve resolution. The encoder size is approximately 1.5×2.0×0.6 mm3. Displacement measurement was performed using a scale with a pitch of 20 μm, and resolution of 0.1 μm has been achieved with signal interpolation
Keywords :
displacement measurement; encoding; integrated optoelectronics; interpolation; laser cavity resonators; lenses; measurement by laser beam; optical sensors; photodetectors; semiconductor lasers; surface emitting lasers; 0.1 micron; 20 micron; displacement measurement; integrated microlenses; monolithic integration; optical micro encoder; phase quadrature; quasi-sinusoidal signals; surface-emitting laser; twin-beam VCSEL; vertical-cavity SEL; Displacement measurement; Integrated optics; Interpolation; Lenses; Microoptics; Performance evaluation; Phase detection; Signal resolution; Surface emitting lasers; Vertical cavity surface emitting lasers;
Conference_Titel :
Solid State Sensors and Actuators, 1997. TRANSDUCERS '97 Chicago., 1997 International Conference on
Conference_Location :
Chicago, IL
Print_ISBN :
0-7803-3829-4
DOI :
10.1109/SENSOR.1997.635450
