Printing of liquid crystal droplet laser resonators on a wet polymer solution and product made therewith

• US 9,720,173 B2
• Filed: 09/15/2016
• Issued: 08/01/2017
• Est. Priority Date: 05/25/2012
• Status: Active Grant

• Current Assignee: Johnson Matthey PLC
• Original Assignee: Johnson Matthey PLC
• Inventors: Coles, Harry, Hutchings, Ian, Gardiner, Damian, Hsiao, Wen-Kai, Hands, Philip, Morris, Stephen, Wilkinson, Timothy
• Primary Examiner(s): RALEIGH, DONALD L
• Application Number:
  US15/266,135
• Publication Number:
  US 20170059775A1
• Time in Patent Office: 320 Days
• CPC Class Codes: B41J 2/01 Ink jet
• CPC Class Codes: G02B 6/1225 comprising photonic band-gap structures or photonic lattices
• CPC Class Codes: G02F 1/13415 Drop filling process
• CPC Class Codes: G02F 2202/36 Micro- or nanomaterials
• CPC Class Codes: H01S 3/08036 using intracavity dispersive, polarising or birefringent elements
• CPC Class Codes: H01S 3/094034 the pumped medium being a dye
• CPC Class Codes: H01S 3/094076 Pulsed or modulated pumping H01S3/1024 takes precedence
• CPC Class Codes: H01S 3/1686 Liquid crystal active layer

Abstract

A method of manufacturing a security feature for identifying objects or documents of value. The method may include the steps of encoding information in a pattern; and ink jet printing a chiral nematic liquid crystal material from a reservoir using a print head on to a substrate in the pattern. Thus, the method forms a patterned array of chiral nematic liquid crystal material deposits. The print head, or the reservoir, or both, may be heated to a temperature above the clearing point of the chiral nematic liquid crystal material. The chiral axes of the chiral nematic liquid crystal material deposits may be aligned substantially perpendicular to the substrate such that a predetermined portion of the electromagnetic spectrum is selectively reflected over other regions of the electromagnetic spectrum by the chiral nematic liquid crystal material deposits.

Claims

1. A method of manufacturing a security feature for identifying objects or documents of value, the method comprising:

encoding information in a pattern; and

ink jet printing a chiral nematic liquid crystal material from a reservoir using a print head on to a substrate in the pattern to form a patterned array of chiral nematic liquid crystal material deposits, wherein the print head, or the reservoir, or both, is heated to a temperature above the clearing point of the chiral nematic liquid crystal material, and wherein the chiral axes of the chiral nematic liquid crystal material deposits are aligned substantially perpendicular to the substrate such that a predetermined portion of the electromagnetic spectrum is selectively reflected over other regions of the electromagnetic spectrum by the chiral nematic liquid crystal material deposits.

2. The method according to claim 1, wherein the pattern is a two-dimensional pattern.

3. The method according to claim 1, wherein the print head is heated to a temperature above the clearing point of the chiral nematic liquid crystal material.

4. The method according to claim 1, wherein the reservoir is heated to a temperature above the clearing point of the chiral nematic liquid crystal material.

5. The method according to claim 1, wherein the print head and the reservoir are heated to a temperature above the clearing point of the chiral nematic liquid crystal material.

6. The method according to claim 1, wherein the predetermined portion of the spectrum is selected to reflect a known portion of the spectrum created by a device equipped with an LED light source where otherwise the material possesses only low visibility to the unaided eye.

7. The method according to claim 1, wherein the chiral nematic liquid crystal material includes a fluorescence dye, a fluorescent laser dye, a quantum dot, or other light harvester or gain additives.