The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 20, 1986
Filed:
Oct. 11, 1985
Frances C Saunders, Malvern Wells, GB;
Abstract
The reflectance of a mirror is variable to provide a dipping car mirror. The mirror comprises a liquid crystal cell formed by two transparent slides coated on their inner surfaces with electrodes. The front electrode is transparent while the rear one is a reflector or a separate reflecting surface is provided. Between the slides is a layer 8 to 12 .mu.m thick of a cholesteric liquid crystal material. The slides are surface treated to give a high tilt homogeneous boundary condition, i.e. the liquid crystal molecules at the slide wall incline at a high (20.degree.-75.degree.) tilt to the surface. A control unit applies either a high voltage (10 volts at 1 kHz) or a low voltage (1 to 2 volts at 1 kHz). The high voltage results in the liquid crystal adopting a light transmissive state. In this state light reflects off the rear of the cell. The low voltage state is a scattering state for the liquid crystal material. In the scattering state light reflects off the front slide and is about 1/10 that reflected off the rear electrode. A photocell controls the switching of the cell. With zero voltage across the cell the liquid crystal material adopts a light transmitter state.