Very thin achromatic quarter wave film laminate for transflective LCD and method for producing the same

• US 8,570,469 B2
• Filed: 12/01/2010
• Issued: 10/29/2013
• Est. Priority Date: 02/27/2006
• Status: Active Grant

• Current Assignee: LG Chem Limited (LG Corporation)
• Original Assignee: LG Chem Limited (LG Corporation)
• Inventors: Yoon, Hyuk, Yoo, Je-Hyuk, Park, Moon-Soo
• Primary Examiner(s): NGO, HUYEN LE
• Application Number:
  US12/958,225
• Publication Number:
  US 20110129598A1
• Time in Patent Office: 1,063 Days
• Field of Search: 349117-119
• US Class Current: 349/119
• CPC Class Codes: C09K 2323/02 Alignment layer characterised by chemical composition
• 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 1/133555 Transflectors
• CPC Class Codes: G02F 1/133638 Waveplates, i.e. plates with a retardation value of lambda/n

Abstract

Disclosed herein is a method for manufacturing a very thin achromatic quarter wave film laminate for transflective LCD including steps of (1) preparing a polymeric substrate oriented in a specific direction; (2) coating a liquid crystal solution on the polymeric substrate; (3) subjecting the coating to drying and UV curing to form a lower liquid crystal layer; (4) coating a solution for an orientation film on the lower liquid crystal layer; (5) drying the coating to form an orientation film; (6) imparting orientation to the orientation film via polarization UV radiation or rubbing; (7) coating a liquid crystal solution on the orientation film; and (8) subjecting the coating to drying and UV curing to form a upper liquid crystal layer. The very thin achromatic quarter wave film laminate for transflective LCD manufactured by this method has a considerably reduced thickness, as compared to conventional quarter wave films in which anisotropic polymeric films are laminated.

Claims

1. A method for manufacturing a very thin achromatic quarter wave film laminate for transflective LCD comprising:

preparing a polymeric substrate oriented in a specific direction;

coating a liquid crystal solution on the polymeric substrate;

subjecting the coating to drying and UV curing to form a lower liquid crystal layer;

coating a solution for an orientation film on the lower liquid crystal layer;

drying the coating to form an orientation film;

imparting orientation to the orientation film via polarization UV radiation or rubbing;

coating a liquid crystal solution on the orientation film; and

subjecting the coating to drying and UV curing to form a upper liquid crystal layer.

2. The method according to claim 1, wherein the orientation film includes 0.1 to 20 parts by weight of light-transmissive particles, based on 100 parts by weight of a base material for the orientation film.

3. The method according to claim 2, wherein the light-transmissive particles have a diameter of 1 to 5μ

m.

4. The method according to claim 3, wherein the light-transmissive particles have a refractive index of 1.4 to 1.7.

5. The method according to claim 1, wherein the liquid crystal solution used in the coating of the lower liquid crystal layer and the upper liquid crystal layer contains photo-polymerizable acrylate.

6. The method according to claim 1, wherein one selected from the lower liquid crystal layer and the upper liquid crystal layer is formed of a ¼

wavelength phase difference film, and the other is formed of a ½

wavelength phase difference film.

7. The method according to claim 6, wherein the liquid crystal solution is coated such that the ¼

wavelength phase difference film has a thickness of 1 to 1.5μ

m.

8. The method according to claim 6, wherein the liquid crystal solution is coated such that the ½

wavelength phase difference film has a thickness of 1.6 to 2.3μ

m.

9. The method according to claim 6, wherein the ¼

wavelength phase difference film and the ½

wavelength phase difference film are coated such that the ¼

wavelength phase difference film crosses the ½

wavelength phase difference film at an angle of 60 to 90 degrees.

10. The method according to claim 1, further comprising:

subjecting the coating to UV curing, after the drying the coating used in formation for an orientation film.

11. The method according to claim 1, wherein the coating of the liquid crystal solution is carried out by solution casting.

12. The method according to claim 1, wherein the coating of the orientation film is carried out by solution casting.

13. The method according to claim 1, further comprising:

coating a material for a first orientation film on the polymeric substrate, followed by drying and polarization UV radiation, prior to the coating a liquid crystal solution on the polymeric substrate to form a lower liquid crystal layer, when imparting orientation to the orientation film via polarization UV radiation.