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

Volume

2

fYear

1997

fDate

16-19 Jun 1997

Firstpage

1233

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;

fLanguage

English

Publisher

ieee

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

Type

conf

DOI

10.1109/SENSOR.1997.635450

Filename

635450