Reflective liquid crystal display device having front scattering films

• US 6,130,735 A
• Filed: 06/08/1998
• Issued: 10/10/2000
• Est. Priority Date: 06/16/1997
• Status: Expired due to Fees

• Current Assignee: Toshiba Matsushita Display Technology (Japan Display Incorporated)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Ogawa, Tetsu, Hatanaka, Takayuki, Fujita, Shingo, Yamaguchi, Hisanori
• Primary Examiner(s): Parker, Kenneth
• Assistant Examiner(s): QI, ZHI QIANG
• Application Number:
  US09/093,184
• Time in Patent Office: 855 Days
• Field of Search: 349/113, 349/114, 349/117, 349/112
• US Class Current: 349/113
• CPC Class Codes: G02F 1/133504 Diffusing, scattering, diffracting elements associated to illuminating devices G02F1/133606
• CPC Class Codes: G02F 2203/02 reflective

Abstract

A reflective liquid crystal display device comprising a polarizer, a retardation film, a front scattering film layer, and a liquid crystal cell having a mirror reflector, in which the front scattering film layer includes at least one film of which scattering angle range is asymmetrical to the normal direction of film. A plural front scattering films of which scattering angle range is asymmetrical to the film normal are laminated so that the projection direction onto the film surface in the central angle direction of the scattering angle range may be different. At least one of the scattering films for composing the scattering film layer is a front scattering film for scattering more strongly the transmission light from the second incident angle region not containing the film normal direction than the transmission light from the first incident angle region containing the film normal direction.

Claims

1. A reflective liquid crystal display device comprising a polarizer, zero, one or a plurality of retardation films, a scattering film layer formed by laminating a plurality of front scattering films strong in front scattering characteristic and almost free from back scattering characteristic, and a liquid crystal cell having a mirror reflector, wherein at least one of said front scattering films for forming said scattering film layer has its scattering angle range asymmetrical to the normal direction of the film.

3. A reflective liquid crystal display device of claim 1, wherein all of said front scattering films for forming said scattering film layer have the projection directions onto each film surface in the central angle direction of their scattering angle ranges in a range of 90°

to 270°

counterclockwise, on the basis of 0°

of the azimuth in the sitting position direction of a viewer observing said reflective liquid crystal display device.

4. A reflective liquid crystal display device of claim 1, wherein two out of said front scattering films for forming said scattering film layer have the projection directions onto each film surface in the central angle direction of their scattering angle ranges forming an angle range of 0°

to 120°

to each other.

5. A reflective liquid crystal display device of claim 1, wherein two out of said front scattering films for forming said scattering film layer have the projection directions onto each film surface in the central angle direction of their scattering angle ranges crossing orthogonally to each other.

6. A reflective liquid crystal display device of claim 1, wherein two out of said front scattering films for forming said scattering film layer have the projection directions onto each film surface in the central angle direction of their scattering angle ranges, at about 135°

and 225°

counterclockwise, on the basis of 0°

of the azimuth in the sitting position direction of a viewer observing said reflective liquid crystal display device.

7. A reflective liquid crystal display device of claim 1, wherein two out of said front scattering films for forming said scattering film layer have the projection directions onto each film surface in the central angle direction of their scattering angle ranges forming an angle of about 180°

to each other.

8. A reflective liquid crystal display device of claim 1, wherein at least one of said front scattering films for forming said scattering film layer has the projection direction onto the film surface in the central angle direction of its scattering angle range, at about 180°

on the basis of 0°

of the azimuth in the sitting position direction of a viewer observing said reflective liquid crystal display device.

2. A reflective liquid crystal display device comprising a polarizer, zero, one or a plurality of retardation films, a scattering film layer formed by laminating a plurality of front scattering films strong in front scattering characteristic and almost free from back scattering characteristic, and a liquid crystal cell having a mirror reflector, wherein all of said front scattering films for forming said scattering film layer have their scattering angle ranges asymmetrical to the normal direction of each film.

9. A reflective liquid crystal display device comprising a liquid crystal cell having liquid crystal charged between a pair of substrates, a polarizer disposed at the side of one substrate of said liquid crystal cell, a retardation film disposed between said polarizer and said liquid crystal cell, a scattering film layer disposed at the side of said one substrate, and a mirror reflector disposed at the side of said other substrate of said liquid crystal cell,

wherein said scattering film layer has an incident angle region for scattering the transmission light more strongly than the incidence from the film layer normal direction.

10. A reflective liquid crystal display device comprising a liquid crystal cell having liquid crystal charged between a pair of substrates, a polarizer disposed at the side of one substrate of said liquid crystal cell, a retardation film disposed between said polarizer and said liquid crystal cell, a scattering film layer disposed at the side of said one substrate, and a mirror reflector disposed at the side of said other substrate of said liquid crystal cell,

wherein said scattering film layer includes a scattering film for scattering the transmission light from a second incident angle region not including the film normal direction more strongly than the transmission light from a first incident angle region including the film normal direction.

11. A reflective liquid crystal display device of claim 10, wherein the scattering characteristic of the transmission light from said first incident angle region and the scattering characteristic of the transmission light from said second incident angle region differ by 45% or more as expressed by the haze rate.

12. A reflective liquid crystal display device of claim 10, wherein the scattering characteristic of the transmission light from said first incident angle region is 20% or less as expressed by the haze rate.

13. A reflective liquid crystal display device of claim 10, wherein the scattering characteristic of the transmission light from said second incident angle region is 50% or more as expressed by the haze rate.

14. A reflective liquid crystal display device of claim 10, wherein said second incident angle region is in a range of 5°

≦

θ

≦

90°

, where θ

is the angle formed by the incident light direction into said scattering film and the film normal (0°

≦

θ

≦

90°

).

15. A reflective liquid crystal display device of claim 14, wherein said second incident angle region is Δ

θ

≧

30°

in terms of θ

, where Δ

θ

is the difference between the maximum value and minimum value of θ

showing said second incident angle region.

16. A reflective liquid crystal display device of claim 10, wherein said second incident angle region is in a range of 90°

≦

φ

≦

270°

, where φ

is the angle formed by the projection component on the film surface in the incident light direction into said scattering film with the reference azimuth in the film surface (0°

≦

φ

<

360°

), and the reference azimuth in the film surface coincides with the sitting position direction of a viewer observing said reflective liquid crystal display device.

17. A reflective liquid crystal display device of claim 10, wherein said scattering film layer includes two or more scattering films laminated so that said second incident angle regions may not be identical.

18. A reflective liquid crystal display device of claim 17, wherein said scattering film layer includes two or more scattering films laminated so that said second incident angle region may be in a range of 60°

≦

φ

≦

300°

, where φ

is the angle formed by the projection component on the film surface in the incident light direction into the scattering film layer with the sitting position direction of a viewer observing said reflective liquid crystal display device (0≦

φ

<

360°

).

19. A reflective liquid crystal display device of claim 18, wherein said scattering film layer includes two or more scattering films laminated so that said second incident angle region may be in a range of 90°

≦

φ

≦

270°

, where φ

is the same as above.