Phase difference plate and manufacturing method thereof, display device

• US 9,995,943 B2
• Filed: 12/12/2013
• Issued: 06/12/2018
• Est. Priority Date: 05/30/2013
• Status: Active Grant

• Current Assignee: BOE Technology Group Co., Ltd.
• Original Assignee: BOE Technology Group Co., Ltd.
• Inventors: Li, Wenbo
• Primary Examiner(s): Frost, Anthony J
• Application Number:
  US14/348,464
• Publication Number:
  US 20150301349A1
• Time in Patent Office: 1,643 Days
• Field of Search: None
• CPC Class Codes: B32B 2457/202 LCD, i.e. liquid crystal displays
• CPC Class Codes: G02B 30/25 using polarisation techniques
• CPC Class Codes: G02B 5/201 in the form of arrays
• CPC Class Codes: G02B 5/3016 involving passive liquid crystal elements optical properties of liquid crystals G02F1/0063; polarising elements associated with active liquid crystal devices G02F1/133528
• CPC Class Codes: G02F 1/13363 Birefringent elements, e.g. for optical compensation
• CPC Class Codes: G02F 1/133631 with a spatial distribution of the retardation value
• CPC Class Codes: G02F 1/133633 using mesogenic materials
• CPC Class Codes: G02F 1/133638 Waveplates, i.e. plates with a retardation value of lambda/n

Abstract

A phase difference plate, a manufacturing method thereof and a display device are provided. The phase difference plate includes: a substrate; and a plurality of strip-shaped regions with an equal width, formed on the substrate and made of liquid crystal photoalignment material, wherein strip-shaped regions in which liquid crystal molecules in the liquid crystal photoalignment material are aligned in a horizontal direction and strip-shaped regions in which liquid crystal molecules in the liquid crystal photoalignment material are aligned in a vertical direction are arranged alternately along an arrangement direction, the horizontal direction is a direction parallel with the substrate and the vertical direction is a direction perpendicular to the substrate.

Claims

1. A phase difference plate, comprising:

a substrate; and

a plurality of strip-shaped regions with an equal width, formed on the substrate and made of liquid crystal photoalignment material,

wherein strip-shaped regions in which all liquid crystal molecules in the liquid crystal photoalignment material are substantially aligned in a horizontal direction and strip-shaped regions in which liquid crystal molecules in the all liquid crystal photoalignment material are substantially aligned in a vertical direction are arranged alternately along an arrangement direction, the horizontal direction is a direction parallel with the substrate and the vertical direction is a direction perpendicular to the substrate,

wherein the liquid crystal photoalignment material is a mixed material of azo liquid crystal material, photopolymerizable monomer, ultraviolet light photoinitiator and visible light photoinitiator, and

in the mixed material, a sum of a mass of the visible light photoinitiator and the ultraviolet light photoinitiator is 5%˜

10% of a mass of the photopolymerizable monomer, a mass of the photopolymerizable monomer is 10%˜

30% of a sum of a mass of the photopolymerizable monomer and the azobenzene liquid crystal, and the mass of each of the visible light photoinitiator and the ultraviolet light photoinitiator is 0.5˜

10% of the mass of the photopolymerizable monomer;

the azo liquid crystal material is one or more of polyurethane type side chain azobenzene liquid crystal, polyyne type side chain azobenzene liquid crystal, polysilane type side chain azobenzene liquid crystal, and polyester type side chain azobenzene liquid crystal.

2. The phase difference plate according to claim 1, wherein under irradiation of light in different wavebands, the liquid crystal molecules in the liquid crystal photoalignment material are aligned in different directions.

3. The phase difference plate according to claim 1, wherein each of the strip-shaped regions has an equal width along the arrangement direction.

4. The phase difference plate according to claim 1, wherein a thickness d of each of the strip-shaped regions satisfies a equation:

d=(m+½

)λ

/Δ

n, wherein m is a nonnegative integer, λ

is a wavelength of incident light, Δ

n is a birefringence of the liquid crystal photoalignment material.

5. The phase difference plate according to claim 4, wherein after transmitting through the strip-shaped regions in which the liquid crystal molecules are aligned in the vertical direction, light is not delayed, and after transmitting through the strip-shaped regions in which the liquid crystal molecules are aligned in the horizontal direction, light has an optical path difference of (m+½

)λ

, wherein m is a nonnegative integer, and λ

is a wavelength of incident light.

6. The phase difference plate according to claim 1, wherein the photopolymerizable monomer is one or more of 1,4-butanediol acrylate, isobornyl acrylate, 1,6-hexanediol diacrylate, polyethanediol diacrylate.

7. The phase difference plate according to claim 1, wherein the ultraviolet light photoinitiator is one or more of 2-hydroxyl-2-methyl-1-phenyl-1-acetone (UV 1173), benzoin diethyl ether (UV 651), 1-hydroxycyclohexyl phenyl ketone (UV 184), 2-methyl-1-(4-methylthio)-phenyl-morpholin-2-yl-1-acetone (UV 907), 2-phenylbenzyl-2-dimethylamino-4-morpholinopropyl phenyl ketone (UV 369), UV 1490, and UV 1700.

8. A display device, comprising:

a display panel, comprising an array substrate and an opposed substrate cell-assembled and comprising a plurality of sub-pixels; and

a phase difference plate according to claim 1, disposed on a light exiting side or a light entering side of the display panel.

9. The display device according to claim 8, wherein a width of each of the strip-shaped regions of the phase difference plate along the arrangement direction is equal to a width of one sub-pixel of the display panel, and a length of each of the strip-shaped regions is integral multiple of a length of one sub-pixel.

10. The display device according to claim 8, wherein the phase difference plate is disposed on the light exiting side of the display panel, the display panel is a liquid crystal display panel, the opposed substrate is a color filter substrate, the display device further comprises a backlight source, a substrate of the phase difference plate is a base substrate of the color filter substrate, the display panel comprises a first polarizer disposed between the base substrate and the phase difference plate or on an light entering side of the base substrate.

11. The display device according to claim 8, wherein the phase difference plate is disposed on the light exiting side of the display panel, the display panel is an organic electroluminescence display panel or a plasma display panel;

a substrate of the phase difference plate is a base substrate of the opposed substrate, and the display panel comprises a first polarizer disposed between the base substrate and the phase difference plate.

12. The display device according to claim 8, wherein the phase difference plate is disposed on the light entering side of the display panel, the display panel is a liquid crystal display panel, the opposed substrate is a color filter substrate and the display device further comprises a backlight source.

13. A manufacturing method of the phase difference plate according to claim 1, comprising the steps:

S1. forming a liquid crystal photoalignment layer on a substrate;

S2. subjecting the liquid crystal photoalignment layer to two exposing processes to form a plurality of strip-shaped regions with an equal width, so that strip-shaped regions in which liquid crystal molecules in the liquid crystal photoalignment material are aligned in a horizontal direction and strip-shaped regions in which liquid crystal molecules in the liquid crystal photoalignment material are aligned in a vertical direction are arranged alternately along an arrangement direction;

wherein the horizontal direction is a direction parallel with the substrate, the vertical direction is a direction perpendicular to the substrate, and the arrangement direction is a direction parallel with the substrate,

wherein the liquid crystal photoalignment material is a mixed material of azo liquid crystal material, photopolymerizable monomer, ultraviolet light photoinitiator and visible light photoinitiator, and

in the mixed material, a sum of a mass of the visible light photoinitiator and the ultraviolet light photoinitiator is 1%˜

20% of a mass of the photopolymerizable monomer, a mass of the photopolymerizable monomer is 1%˜

40% of a sum of a mass of the photopolymerizable monomer and the azobenzene liquid crystal, and the mass of each of the visible light photoinitiator and the ultraviolet light photoinitiator is 0.5˜

10% of the mass of the photopolymerizable monomer.

14. The manufacturing method of the phase difference plate according to claim 13, wherein the step S2 comprises the steps:

S10. placing a mask with light-transmitting regions and light-shielding regions alternately arranged over the liquid crystal photoalignment layer;

S20. exposing the liquid crystal photoalignment layer using the ultraviolet light through the light-transmitting regions to form strip-shaped regions in which liquid crystal molecules are aligned in a vertical direction; and

S30. exposing all of the liquid crystal photoalignment layer using the visible light to form strip-shaped regions in which liquid crystal molecules are aligned in a horizontal direction.

15. The manufacturing method of the phase difference plate according to claim 13, wherein the step S2 comprises the steps:

S10. placing a mask with light-transmitting regions and light-shielding regions alternately arranged over the liquid crystal photoalignment layer;

S20. exposing the liquid crystal photoalignment layer using the light-transmitting regions of the mask by means of ultraviolet light to form strip-shaped regions in which liquid crystal molecules are aligned in a vertical direction; and

S30. moving the mask to exchange positions of the light-transmitting regions and the light-shielding regions;

S40. exposing the liquid crystal photoalignment layer using the light-transmitting regions of the mask by means of visible light to form strip-shaped regions in which liquid crystal molecules are aligned in a horizontal direction;

Or, the step S40 is before the step S20.

16. The manufacturing method of the phase difference plate according to claim 13, wherein the step S1 comprises steps:

forming a plurality of grooves with an equal width on a substrate;

injecting liquid crystal photoalignment materials which are cured respectively by visible light and ultraviolet light into the plurality of grooves,

wherein in the step S2, the liquid crystal photoalignment layer is exposed by respectively using the visible light and the ultraviolet light.

17. The manufacturing method of the phase difference plate according to claim 13, wherein conditions for the step S2 are:

room temperature, exposure time of 0.1-15 minutes and light intensity of over 10 mW.