Liquid crystal display panel

• US 7,911,557 B2
• Filed: 10/01/2008
• Issued: 03/22/2011
• Est. Priority Date: 03/26/2004
• Status: Expired due to Fees

• Current Assignee: Nitto Denko Corporation
• Original Assignee: Nitto Denko Corporation
• Inventors: Paukshto, Michael V., Lazarev, Pavel I.
• Primary Examiner(s): Nelms; David
• Assistant Examiner(s): Briggs; Nathanael R
• Application Number:
  US12/285,273
• Publication Number:
  US 20090040431A1
• Time in Patent Office: 902 Days
• Field of Search: 349/65, 349/62, 349/96, 349/165, 428/1.1
• US Class Current: 349/62
• CPC Class Codes: C09K 2323/00 Functional layers of liquid crystal optical display excluding electroactive liquid crystal layer characterised by chemical composition
• CPC Class Codes: G02B 6/0056 for producing polarisation effects, e.g. by a surface with polarizing properties or by an additional polarizing elements
• CPC Class Codes: G02F 1/133514 Colour filters
• CPC Class Codes: G02F 1/133521 Interference filters
• CPC Class Codes: G02F 1/133536 Reflective polarizers G02F1/13362 takes precedence
• CPC Class Codes: G02F 1/13362 providing polarized light, e.g. by converting a polarisation component into another one
• CPC Class Codes: G02F 2201/17 Multi-pass arrangements, i.e. arrangements to pass light a plurality of times through the same element, e.g. by using an enhancement cavity

Abstract

The present invention relates to a liquid crystal display panel with improved image contrast comprising an array of pixel regions and a sequence of a recycling backlight structure comprising broadband rear interference polar (RI-Polar) having a transmission axis AB with preset orientation, a spatial intensity modulation structure comprising a broadband front interference polar (FI-Polar) having a transmission axis approximately parallel to the transmission axis AB, a spectral filtering structure, and antireflection means. Each said pixel region spatially encompasses a plurality of subpixel regions. The RI-Polar and FI-Polar are multilayer structures of stacked layers. At least one layer of each structure is optically anisotropic, made by means of Cascade Crystallization Process and characterized by a globally ordered biaxial crystalline structure with an intermolecular spacing of 3.4±0.3 Å in the direction approximately parallel to the transmission axis AB. Said layer is transparent in the wavelength band of visible light, and is formed by rodlike supramolecules, which represent at least one polycyclic organic compound with a conjugated π-system and ionogenic groups.

Claims

1. A liquid crystal display panel with improved image contrast comprising an array of pixel regions and a sequence of elements comprising

a recycling backlight structure comprising a broadband rear interference polar (RI-Polar) having a transmission axis AB with preset orientation,

a spatial intensity modulation structure for modulating the light of each pixel region,

a broadband front interference polar (FI-Polar) having a transmission axis approximately parallel to the transmission axis AB,

a spectral filtering structure associated with each said pixel region,

wherein said RI-Polar and said FI-Polar are multilayer structures of stacked layers and at least one layer of each multilayer structure is optically anisotropic, being made by means of Cascade Crystallization Process, and

characterized by a globally ordered biaxial crystalline structure with an intermolecular spacing of 3.4±

0.3 Å

in the direction approximately parallel to the transmission axis AB, is transparent in the wavelength band of visible light, and is formed by rodlike supramolecules which represent at least one polycyclic organic compound with a conjugated π

-system and ionogenic groups.

2. The liquid crystal display panel according to claim 1, wherein the spatial intensity modulation stricture further comprises an array of polarization direction rotating elements neighboring with the backlight structure, and wherein the broadband front interference polar (FI-Polar) neighboring with the spectral filtering structure.

3. The liquid crystal display panel according to claim 1, further comprising an antireflection mean disposed on an external surface of said display panel.

4. The liquid crystal display panel according to claim 1, wherein the pixel regions spatially encompass a plurality of subpixel regions, the spectral filtering structure further comprises a pixelated array of color filters, and the spatial intensity modulation structure includes a plurality of subpixel regions.

5. The liquid crystal display panel according to claim 1, wherein the backlight structure further comprises:

a light guide having a front surface facing the spatial intensity modulation structure, a rear surface, and an edge;

a light source optically connected to the edge of the light guide and emitting light into the light guide;

a broadband reflector capable of reflecting and randomizing light that is incident upon said reflector and which is situated on the rear surface of the light guide,

the broadband rear interference polar (RI-Polar) situated on the front surface of the light guide; and

a rear broadband sheet polarizer situated on the RI-Polar and having a transmission axis approximately parallel to the transmission axis AB.

6. The liquid crystal display panel according to claim 1, wherein at least one layer of the RI-Polar is made of a fluorescent material converting ultraviolet radiation into visible light.

7. The liquid crystal display panel according to claim 1, wherein at least one transparent layer of each said multilayer structure has a fundamental absorption edge below 400 nm.

8. The liquid crystal display panel according to claim 1, wherein at least one transparent layer of each said multilayer structure has a transmission coefficient of not less than 0.98.

9. The liquid crystal display panel according to claim 1, wherein at least one transparent layer of each said multilayer structure is uniformly transparent in the wavelength band of visible light.

10. The liquid crystal display panel according to claim 1, wherein at least one optically anisotropic layer is treated with ions of divalent and/or trivalent metals.

11. The liquid crystal display panel according to claim 1, wherein molecules of at least one organic compound material comprise heterocycles.

12. The liquid crystal display panel according to claim 1, wherein at least one optically anisotropic layer is manufactured from a lyotropic liquid crystal based on at least one dichroic dye.

13. The liquid crystal display panel of claim 2, wherein each said polarization direction rotating element is made of a liquid crystal material.

14. The liquid crystal display panel of claim 5, wherein said broadband reflector is a quasi-diffusive reflector.

15. The liquid crystal, display panel according to claim 3, wherein the antireflection mean is a front broadband sheet polarizer having a transmission axis approximately parallel to the transmission axis AB.

16. The liquid crystal display panel according to claim 9, wherein at least the one transparent layer of each said multilayer structure shows transmission coefficient of not more than 75% across a wavelength range of 450-80 nm to parallel polarized light.

17. The liquid crystal display panel according to claim 9, wherein at least the one transparent layer of each said multilayer structure shows transmission coefficient of not less than 75% across a wavelength range of 450-80 nm to perpendicularly polarized light.