Device for submicrosecond electro-optic modulation in the liquid crystal smectic-A phase using orthogonal bookshelf geometry

US4838663A · kind A · utility

Assignee

• S.A.R.L. S T Lagerwall · FR

Inventors

• Sven T. Lagerwall · Göteborg, SE
• Gunnar Andersson
• Ingolf Dahl · Mölndal, SE
• Wojciech Kuczynski · Gothenburg, SE
• Kent Sharp · Lindome, SE
• Bengt Stebler · Göteborg, SE

Key dates

• Filing date: Oct 7, 1987
• Grant date: Jun 13, 1989
• Expiry date: Oct 7, 2007

Classification

• Technology area (CPC G): Physics
• CPC primary: G02F1/1418
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

A new liquid crystal electro-optic device similar to the SSFLC device is described. It uses the same kind of polar chiral smectics and the same geometry as the SSFLC device (thin sample in the "book-shelf" layer arrangement) but instead of using a tilted smectic phase like the C* phase, it utilizes the above-lying, essentially non-ferroelectric A phase. The achievable optical intensity modulation is considerably lower than for the SSFLC device, but the device is about one hundred times faster. It is thus appropriate for modulator rather than for display applications. Sample fabrication is simpler and, finally, the device is insensitive to polarization compensation from external charges. The electro-optic switching at moderate applied voltages can be detected through the full range of the A phase.