Microfabricated confocal microscopes using scanning doublet objective lenses

Conventional laser scanning confocal microscopes widely used in biological imaging and metrology are bulky bench-top instruments. Size reduction and portability are desired for applications such as in vivo imaging, planetary investigation, and handheld micro total analysis systems. We report in this thesis a new miniature microscope of which major components are integrated within 2 mm3 using micromachining and transmissive scanning. It is small enough to be arrayed on a chip scale, and may be batch manufactured.; The microfabricated confocal microscope incorporates electrostatically-actuated microlenses for the focusing and scanning. Objective lenses, scanners, a pupil and a pinhole of the miniaturized confocal microscope are microfabricated and vertically integrated by stacking multiple dies. The objective lenses are composed of two vertically cascaded polymer microlenses integrated into micromachined comb actuators. Raster scanning is implemented by electrostatically actuating each microlens in orthogonal directions. We have demonstrated reflection confocal imaging with 3 mum transverse resolution over a 100 mum field of view and a 0.38 mm working distance at lambda = 633 nm.; The first part of this thesis describes design, fabrication and characterization of various micromachined optical components: polymer microlenses, microlens scanners, two-axis micromirrors, and variable focus liquid lenses. Polymer microlenses are fabricated on micromachined silicon ring lens holders using microinjection. Microlens scanners are developed to electrostatically actuate the polymer microlens. Stacked 2D microlens scanners are demonstrated to achieve raster scanning by stacking multiple microlens scanners. Vertical microlens scanners are developed for focus control of imaging system using vertical comb drives. Along the way, a two-axis micromirror is developed based on a new backside island isolation method. A variable focus liquid lens is demonstrated using switchable electrowetting.; The second part of this thesis focuses on system level integration of those components and applications of the integrated microscope system. Micro confocal line scanning system is demonstrated as a laser induced fluorescent scanner for multiplexed microfluidics. Finally, a prototype of the microfabricated confocal microscope is built by hybrid integration of the stacked microlens scanners and an off-the-shelf solid state laser and detector. 2D reflectance confocal imaging is demonstrated using the micromachined transmissive confocal microscope.