METHOD OF WAFER SCALE FABRICATION, ASSEMBLY AND ELECTRICAL CONNECTION OF A LIQUID CRYSTAL ELECTRO-OPTIC DEVICE

• US 20170255047A1
• Filed: 06/25/2015
• Published: 09/07/2017
• Est. Priority Date: 06/25/2014
• Status: Active Grant

• Current Assignee: LensVector, Inc.
• Original Assignee: LensVector, Inc.
• Inventors: GALSTIAN, Tigran, BAGRAMYAN, Aram, TORK, Amir
• Granted Patent: US 11,042,064 B2
• Time in Patent Office: Days
• CPC Class Codes: G02F 1/133351 Manufacturing of individual cells out of a plurality of cells, e.g. by dicing
• CPC Class Codes: G02F 1/1337 Surface-induced orientation of the liquid crystal molecules, e.g. by alignment layers
• CPC Class Codes: G02F 1/13394 spacers regularly patterned on the cell subtrate, e.g. walls, pillars G02F1/133377 takes precedence
• CPC Class Codes: G02F 1/1341 Filling or closing of cells
• CPC Class Codes: G02F 1/134309 characterised by their geometrical arrangement
• CPC Class Codes: G02F 1/1347 Arrangement of liquid crystal layers or cells in which the final condition of one light beam is achieved by the addition of the effects of two or more layers or cells
• CPC Class Codes: G02F 2203/07 Polarisation dependent

Abstract

A method of wafer level manufacturing, separating and electrical connection of liquid crystal optical devices is disclosed. An electro-optic device having at least one liquid crystal cell for providing spatially variable control of light is also described. The electro-optic device includes: a pair of opposed substrates, each substrate having a lateral extent; a pair of electrodes for applying an electric field therebetween, each electrode having a pattern and being deposited on a corresponding substrate, each electrode having an electrical contact area extending to at least one side of the corresponding substrate; a pair of alignment layers sandwiching a liquid crystal layer therebetween, the alignment layers defining a predominant orientation direction for liquid crystal molecules of the liquid crystal layer; and a liquid crystal reservoir wall defining a lateral extent of the liquid crystal layer, the liquid crystal reservoir wall being spaced from at least one side of each substrate such that each electrode electrical contact area is exposed to air in an air gap between the substrates.

Claims

1. An electro-optic device having at least one liquid crystal cell for providing spatially variable control of light, the electro-optic device comprising:

a pair of opposed substrates, each substrate having a lateral extent;

a pair of electrodes for applying an electric field therebetween, each electrode being deposited on a corresponding substrate, each said electrode having an air-exposed electrical contact area extending to at least one side of said corresponding substrate;

a pair of alignment layers sandwiching a liquid crystal layer therebetween, said alignment layers defining a predominant orientation direction for liquid crystal molecules of said liquid crystal layer; and

a liquid crystal reservoir wall defining a lateral extent of said liquid crystal layer, said liquid crystal reservoir wall being spaced from said at least one side of each substrate such that each said electrical contact area of said electrodes is exposed in an air gap between said substrates.

2. A device as claimed in claim 1, wherein each electrical contact area extends to the same side of said substrates.

3. A device as claimed in claim 1, wherein said substrates have the same lateral extent.

4. A device as claimed in claim 1, wherein said substrates have different lateral extent.

5. A device as claimed in claim 1, wherein said reservoir wall comprises spacers defining a thickness of said liquid crystal reservoir.

15. In combination, the electro-optic device as defined in claim 1 and a lead frame comprising an insertion guide for receiving a side of the electro-optic device and at least one contact member inserted into said gap and making electrical contact with one of said pair of electrodes.

16. The combination as defined in claim 15, wherein said contact member comprises one or more resilient metal strips with curled ends to be biased against said one of said pair of electrodes.

17. The combination as defined in claim 15, wherein said lead frame forms part of a mounting for said electro-optic device.

18. The combination as defined in claim 15, wherein said lead frame provides four electrode connections.

19. The combination as defined in claim 15, comprising two said lead frames for receiving opposed sides of the electro-optic device.

20. The combination as defined in claim 15, wherein said contact member comprises conductive adhesive.

6. A method of wafer level manufacture of a plurality of polarization dependent electro-optic devices, the method comprising:

depositing a corresponding top and bottom electrode layer of electrode material on a corresponding one of a top and bottom wafer substrates, each electrode layer defining electrical contact areas for each electro-optic device;

depositing a corresponding top and bottom liquid crystal alignment layer on a corresponding one of said top and bottom electrode layers;

imparting an orientation direction to each orientation layers;

forming a closed liquid crystal reservoir wall for each device over said bottom alignment layer, each said liquid crystal reservoir wall having a perimeter configured to leave said electrical contact areas outside of said liquid crystal reservoir exposed to air;

dispensing a liquid crystal material within each reservoir wall; and

forming an array of liquid crystal cells by applying said top substrate with said alignment layer down on top of said bottom substrate such that said electrical contact areas remain exposed to air between said substrates outside said liquid crystal reservoir wall, said liquid crystal alignment layers having one of same and opposing alignment directions, said top and bottom liquid crystal alignment layers defining a liquid crystal alignment orientation.

7. A method as claimed in claim 6, wherein in forming said liquid reservoir wall comprises spacers defining a thickness of each liquid crystal reservoir.

8. A method as claimed in claim 6, comprising reservoir depressions formed in at least one of said wafer substrates.

9. A method as claimed in claim 6, comprising scribing said top substrate of said wafer array of polarization dependent liquid crystal electro-optic devices in a pattern to define extents of each device thereon.

10. A method as claimed in claim 9, wherein scribing said top substrate comprises one of a mechanically scribing said top substrate with a diamond tip and laser scribing at least said top substrate with a laser.

11. A method of wafer level manufacture of a plurality of polarization independent electro-optical device, the method comprising:

wafer level manufacturing a pair of wafers having corresponding pluralities of polarization dependent electro-optic devices in accordance with claim 6;

rotating at least one of the wafers of polarization dependent electro-optic devices with respect to the other wafer of polarization dependent electro-optic devices such that liquid crystal alignment orientations between the wafers of polarization dependent electro-optic devices are orthogonal to each other;

applying a thin layer of transparent adhesive to one of the wafers;

bonding the wafers of polarization dependent electro-optic devices into a wafer of polarization independent electro optic devices;

scribing a top-most substrate of said wafer of polarization independent electro optic devices to define extends of each device thereon;

scribing a bottom-most substrate of said wafer of polarization independent electro optic devices to define extends of each device thereon; and

singulating said polarization independent electro-optic devices from the wafer thereof.

12. A method as claimed in claim 11, wherein scribing said top-most substrate and scribing said bottom-most substrate comprises employing the same scribe pattern as said scribe pattern scribed on said top substrate.

13. A method as claimed in claim 11, wherein scribing said top-most substrate and scribing said bottom-most substrate comprises employing the a different scribe pattern from a scribe pattern scribed on said top substrate.

14. A method as claimed in claim 13, further comprising covering said air exposed electrical contact areas with a metal layer for enabling direct soldering of external wiring to said electrode layers.