| US 7,573,549 B2 | ||
| Optical device, polarizing plate, diffuser, diffusing film, polarizing film and liquid crystal image display apparatus | ||
| Takashi Nishihara, Soka (Japan); Hideaki Homma, Ashikaga (Japan); Yusuke Tochigi, Tokyo (Japan); and Shigetomo Sakakibara, Koshigaya (Japan) | ||
| Assigned to Toppan Printing Co., Ltd., Tokyo (Japan) | ||
| Filed on Aug. 27, 2007, as Appl. No. 11/892,787. | ||
| Claims priority of application No. P2006-232137 (JP), filed on Aug. 29, 2006; application No. P2006-239955 (JP), filed on Sep. 05, 2006; and application No. P2006-262012 (JP), filed on Sep. 27, 2006. | ||
| Prior Publication US 2008/0055523 A1, Mar. 06, 2008 | ||
| Int. Cl. G02F 1/1335 (2006.01) | ||
| U.S. Cl. 349—112 | 20 Claims |
| 1. An optical device for a liquid crystal display apparatus that displays an image, the optical device being arranged at a
front side of the liquid crystal display apparatus, comprising:
a plastic-based film; and
a diffusing layer formed at least one surface of the plastic-based film and scatters light that passes through the diffusing
layer, the diffusing layer including:
a medium; and inner scattering elements that selectively Mie-scatter visible light having a wavelength range of 400 nm to
500 nm into the medium, the inner scattering elements having a refraction index different from a refraction index of the medium,
wherein the diffusing layer has pencil hardness of equal to or more than 2H under a 500 g-load specified in ISO/DIS 15184,
and
wherein, when the optical device is arranged at the front side of the liquid crystal display apparatus that displays color
near eight test colors specified in CIE 1974, as a test color, the optical device being formed so that chrominance Δu′v′ obtained
according to the following Equation 1 is equal to or less than 0.05, based on a chromaticity coordinate (u0′, v0′) of CIE1976UCS observed in the front side and a chromaticity coordinate (u′, v′) of CIE1976UCS observed at an observation
angle of ±60 degrees in horizontal and vertical directions of a screen of the liquid crystal display apparatus when a direction
perpendicular to the screen is assumed to be 0 degrees
Δu′v′={(u′−u0′)2+(v′−v0′)2}0.5 [Equation 1].
|