Fluorescent liquid crystals

• US 3,960,753 A
• Filed: 05/30/1974
• Issued: 06/01/1976
• Est. Priority Date: 05/30/1974
• Status: Expired due to Term

• Current Assignee: RCA Corporation (General Electric Company)
• Original Assignee: RCA Corporation (General Electric Company)
• Inventors: Larrabee, Robert Dean
• Primary Examiner(s): Padgett, Benjamin R.
• Assistant Examiner(s): Cron, T. S.
• Application Number:
  US05/474,600
• Time in Patent Office: 733 Days
• Field of Search: 252/299, 252/408 LC, 252/301.2 R, 252/301.3 R, 350/150, 350/160 LC, 23/230 LC, 428/1, 73/356
• US Class Current: 252/299.1
• CPC Class Codes: C09K 11/06 containing organic luminescent materials
• CPC Class Codes: C09K 19/22 linked by a chain containing carbon and nitrogen atoms as chain links, e.g. Schiff bases
• CPC Class Codes: C09K 19/52 characterised by components which are not liquid crystals, e.g. additives with special physical aspect: solvents, solid particles
• CPC Class Codes: G01K 11/165 of organic liquid crystals
• CPC Class Codes: G02F 1/13762 containing luminescent or electroluminescent additives

Abstract

Liquid crystal compositions compositions and liquid crystal thermometric articles, radiation sensors, and optical display devices comprised of a nematic liquid crystal solvent which is effectively transparent to radiation of near ultraviolet and visible wavelengths and a fluorescent solute whose visible fluorescent intensity varies with the phase or orientation of the liquid crystal solvent are disclosed.

Claims

1. A composition which exhibits fluorescent intensity variations at its solid to mesomorphic or mesomorphic to isotropic phase transition comprising a solution of one or a mixture of liquid crystal compounds of the formula ##SPC7##

wherein R is C_n H_2n+1 -- or C_n H_2n+1 CO-- and n is an integer from 1-10 and an amount of 2, 4, 6-trimethylpyridinium tetrakis [1, 1, 1-trifluoro-4-(p-trifluoromethylphenyl)-2, 4-butenedioxo] europium III effective to induce said variations.

2. The composition of claim 1 wherein said liquid crystal compound is p-n-hexacyloxybenzylidene-p'"'"'-aminobenzonitrile.

3. The composition of claim 1 wherein said liquid crystal compound is p-n-heptacyloxybenzylidene-p'"'"'-aminobenzonitrile.

4. The composition of claim 1 wherein said liquid crystal compound is p-n-hexoxybenzylidene-p'"'"'-aminobenzonitrile.

5. The composition of claim 1 wherein said mixture of liquid crystal compounds is an equimolar mixture of p-n-hexacyloxybenzlidene-p'"'"'-aminobenzonitrile, p-n-heptacyloxybenzylidene-p'"'"'-aminobenzonitrile, and p-n-hexoxybenzylidene-p'"'"'-aminobenzonitrile.