Electrode Design for Tunable Microlenses

15th May 199

Microlenses immersed in nematic liquid crystal with electrically controllable focal length

A microlens immersed in a nematic liquid crystal cell has been constructed with avariable focal length which can be controlled by applying an analogue voltage to thenematic liquid crystal. The focal length is -910 ± 30 ? m with no electric field appliedand with an applied field the focal length can be varied from 380 ± 50 to 560 ± 20 ? malthough at present the lens performance is limited by aberrations. A microlens immersed in a nematic liquid crystal cell has been constructed with avariable focal length which can be controlled by applying an analogue voltage to thenematic liquid crystal. The focal length is -910 ± 30 ? m with no electric field appliedand with an applied field the focal length can be varied from 380 ± 50 to 560 ± 20 ? malthough at present the lens performance is limited by aberrations. 12 May 199

Variable-focus microlenses as a potential technology for endoscopy

Using a new device which contains an array of microlenses whose focal lengths can be electrically varied, we have been able to control the input from one microlens to a single mode fibre using an applied voltage. For such a microlens array many closely-spaced focal spots can be generated in parallel, and electrically switched to address, potentially, an array of receiver fibres. We show how the particular switching characteristics of the device, whereby the lenses switch from diverging to converging, serves in turn to disperse light and to focus it into the fibre