Transflective film, transflective polarizer, and polarizing light source device and liquid crystal display device using the same

• US 7,820,252 B2
• Filed: 06/28/2002
• Issued: 10/26/2010
• Est. Priority Date: 07/02/2001
• Status: Expired due to Fees

• Current Assignee: Sumitomo Chemical Company Limited
• Original Assignee: Sumitomo Chemical Company Limited
• Inventors: Sairai, Takuya, Higashi, Koji, Honda, Masaru
• Primary Examiner(s): HON, SOW FUN
• Application Number:
  US10/183,356
• Publication Number:
  US 20030082314A1
• Time in Patent Office: 3,042 Days
• Field of Search: 428/1.31, 428/1.5, 428/1.3, 359/487, 359/502, 359/569, 359/572, 359589-590, 349/62, 349/67, 349 96- 97, 349/114
• US Class Current: 428/1.3
• CPC Class Codes: C09K 2323/03 Viewing layer characterised by chemical composition
• CPC Class Codes: C09K 2323/031 Polarizer or dye
• CPC Class Codes: G02F 1/133555 Transflectors
• CPC Class Codes: G02F 1/13362 providing polarized light, e.g. by converting a polarisation component into another one
• CPC Class Codes: Y10T 428/24355 Continuous and nonuniform or irregular surface on layer or component [e.g., roofing, etc.]

Abstract

The present invention provides a transflective film comprising a polymer film having an in-plane phase retardation value of about 30 nm or less and a transflective layer made of an inorganic compound, wherein the transflective layer is coated on the polymer film and a reflectance of the transflective film is from about 10% to about 95%. When an absorption-type polarizer is laminated to the polymer film side of the transflective film, a transflective polarizer is provided. When a reflection-type polarizer is laminated to the transflective layer side of the transflective film, a transflective polarizer used in a system improving luminance is provided. Using these transflective polarizers, a polarizing light source device and a transflective liquid crystal display device are provided.

Claims

1. A transflective film comprising a polymer film having an in-plane phase retardation value of about 30 nm or less and a single transflective layer consisting of at least one layer made of an inorganic compound, not of metal or polymer, wherein the transflective layer is coated on the polymer film in a continuous layer, the transflective layer has an utilization efficiency of light from about 80% to about 100%, a refractive index of the inorganic compound is about 1.9 or more and a reflectance of the transflective film is from about 10% to about 95%, and

wherein when the transflective layer is a single layer structure, the optical thickness of the transflective layer is one-fourth of the specific wavelength in the visible region, and

when the transflective layer is a multi layer structure, the optical thickness of at least one layer composing the transflective layer is one-fourth of the specific wavelength in the visible region.

2. The transflective film according to claim 1, wherein a rough surface is formed on at least one surface of the polymer film and the transflective layer is coated on this rough surface.

3. A transflective polarizer comprising the transflective film according to claim 1 and an absorption-type polarizer laminated on the transflective film.

4. The transflective polarizer according to claim 3, wherein a reflection-type polarizer is further laminated on the opposite side to the absorption-type polarizer so that the reflection-type polarizer faces the transflective film.

7. The transflective polarizer according to any of claims 3 to 6, additionally comprising at least one light diffusing layer.

8. The transflective polarizer according to claim 7, wherein the light diffusing layer has an in-plane phase retardation value of about 30 nm or less.

9. The transflective polarizer according to claim 8, wherein the light diffusing layer has an adhesive property.

10. The transflective polarizer according to claim 8, wherein at least two adjacent films or layers are closely laminated with a pressure-sensitive adhesive.

11. The transflective polarizer according to claim 7, wherein the light diffusing layer has an adhesive property.

12. The transflective polarizer according to claim 11, wherein at least two adjacent films or layers are closely laminated with a pressure-sensitive adhesive.

13. The transflective polarizer according to claim 7, wherein at least two adjacent films or layers are closely laminated with a pressure-sensitive adhesive.

14. A polarizing light source device comprising the transflective polarizer according to any of claims 3 to 6 and a light source member and a reflector, wherein the light source member and reflector are placed in this order on the polymer film side of the transflective polarizer.

15. A transflective liquid crystal display device comprising the polarizing light source device according to claim 14, a liquid crystal cell and an absorption-type polarizer placed at a front side of a liquid crystal cell, wherein the liquid crystal cell and the absorption-type polarizer are placed in this order on the transflective polarizer side of the polarizing light source device.

16. The transflective liquid crystal display device according to claim 15, wherein a light diffusing layer is laminated between the liquid crystal cell and the absorption-type polarizer.

17. The transflective liquid crystal display device according to claim 16, wherein at least one pair of members from the transflective polarizer to the absorption-type polarizer are closely laminated with a pressure-sensitive adhesive.

18. The transflective liquid crystal display device according to claim 15, wherein at least one pair of members from the transflective polarizer to the absorption-type polarizer are closely laminated with a pressure-sensitive adhesive.

5. A transflective polarizer comprising a polymer film having one surface on which a single transflective layer consisting of at least one layer made of an inorganic compound, not of metal or polymer, is formed in a continuous layer, a reflection-type polarizer and an absorption-type polarizer, wherein the polymer film, the reflection-type polarizer and the absorption-type polarizer are laminated in this order, wherein the transflective layer has an utilization efficiency of light from about 80% to about 100%, and a refractive index of the inorganic compound is about 1.9 or more, and

wherein when the transflective layer is a single layer structure, the optical thickness of the transflective layer is one-fourth of the specific wavelength in the visible region, and

when the transflective layer is a multi layer structure, the optical thickness of at least one layer composing the transflective layer is one-fourth of the specific wavelength in the visible region.

6. A transflective polarizer comprising a polymer film formed in an irregular shape on at least one surface thereof and a single transflective layer consisting of at least one layer made of an inorganic compound, not of metal or polymer, on the irregular shape in a continuous layer, a reflection-type polarizer and an absorption-type polarizer, wherein the polymer film, the reflection-type polarizer and the absorption-type polarizer are laminated in this order, wherein the transflective layer has an utilization efficiency of light from about 80% to about 100%, and a refractive index of the inorganic compound is about 1.9 or more, and

wherein when the transflective layer is a single layer structure, the optical thickness of the transflective layer is one-fourth of the specific wavelength in the visible region, and

when the transflective layer is a multi layer structure, the optical thickness of at least one layer composing the transflective layer is one-fourth of the specific wavelength in the visible region.