# US 11,029,568 B2 · Photoalignment agent and liquid crystal display device including the same

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- Number: US 11,029,568 B2
- Document ID: US11029568B2
- Status: Granted
- Kind: B2
- Application number: 15/863,281
- Filed: 2018-01-05
- Published: 2018-05-10
- Granted: 2021-06-08
- Earliest claimed: 2014-02-21
- Assignees: Samsung Display Co., Ltd.
- Applicants: Samsung Display Co., Ltd.
- Inventors: Suk Hoon Kang; Yeong Rong Park; Mi Hwa Lee; Jun Woo Lee; Baek Kyun Jeon
- Web page: https://patentgrep.com/patent/US11029568B2

## CPC

- G02F 1/133723: {Polyimide, polyamide-imide}
- C08G 73/1042: {Copolyimides derived from at least two different tetracarboxylic compounds or two different diamino compounds}
- C08G 73/1078: {wholly aromatic in the diamino moiety}
- C09D 179/08: Polyimides; Polyester-imides; Polyamide-imides; Polyamide acids or similar polyimide precursors
- C09K 2323/027: Polyimide
- G02F: OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- C08G: MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C09D: COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR (cosmetics A61K; processes for applying liquids or other fluent materials to surfaces, in general, B05D; staining wood B27K5/02; glazes or vitreous enamels C03C; natural resins, French polish, drying-oils, driers, turpentine, per se, C09F; polishing compositions other than French polish, ski waxes C09G; adhesives or use of materials as adhesives C09J; materials for sealing or packing joints or covers C09K3/10; materials for stopping leaks C09K3/12; processes for the electrolytic or electrophoretic production of coatings C25D)
- C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE

## Abstract

A photoalignment agent is provided. The photoalignment agent includes a copolymer of ii) at least one of a cyclobutanedianhydride (CBDA) and a cyclobutanedianhydride (CBDA) derivative, and ii) a diamine, and the diamine includes an electron donor group.

## Claims

### Claim 1

A liquid crystal display comprising:
a first substrate;
a thin film transistor disposed on the first substrate;
a first electrode connected to the thin film transistor; and
a first alignment layer disposed on the first electrode,
wherein the first alignment layer comprises a copolymer of cyclobutanedianhydride, a cyclobutanedianhydride derivative, a first diamine, and a second diamine,
wherein a residual structure of the first diamine in the copolymer includes a group to donate an unshared pair of electrons and a residual structure of the second diamine in the copolymer does not include a group to donate an unshared pair of electrons,
wherein a repeating unit of the copolymer is a compound represented by Formula O:
wherein X1, X2, X3 and X4 are independently hydrogen, fluorine, or an organic compound; at least one among X1, X2, X3 and X4 is not hydrogen; and R1 and R2 are independently hydrogen or an alkyl group; and the organic compound is an alkyl group having a carbon number of 1 to 6.

### Claim 2 (depends on 1)

The liquid crystal display of claim 1, wherein
the first diamine is present in an amount of about 10% to about 30% based on the total weight of the first diamine and the second diamine.

### Claim 3 (depends on 1)

The liquid crystal display of claim 1, further comprising
a second electrode disposed on the first substrate,
an insulating layer disposed between the first electrode and the second electrode, wherein the first electrode includes a plurality of branch electrodes, and the second electrode has a planar shape.

### Claim 4 (depends on 3)

The liquid crystal display of claim 3, wherein
the plurality of branch electrodes overlap the second electrode having the planar shape.

### Claim 5 (depends on 4)

The liquid crystal display of claim 4, further comprising
a passivation layer disposed between the thin film transistor and the second electrode, wherein the thin film transistor and the first electrode are connected by a contact hole defined in the passivation layer and the insulating layer.

### Claim 6 (depends on 1)

The liquid crystal display of claim 1, further comprising:
a second substrate facing the first substrate;
a second alignment layer disposed on the second substrate; and
a liquid crystal layer disposed between the first substrate and the second substrate, wherein the liquid crystal layer comprises liquid crystal molecules,
wherein the second alignment layer comprises a same material as the first alignment layer.