Anisotropic scattering sheet

An anisotropic, diffuser technology, applied in the field of transmissive liquid crystal display devices and their flat or flat light source equipment, can solve problems such as unsuitable for long-term stable use, uneven brightness, etc.

Inactive Publication Date: 2006-09-13
DAICEL CHEM IND LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Therefore, the film becomes shrunk or wrinkled when the film is used, and then brightness unevenness may occur due to the shrunk or wrinkle in some cases
Therefore, these films or sheets are not suitable for long-term stable use

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0220] Use 91 parts by weight of crystalline polypropylene resin PP (manufactured by Grand Polymer Co.; F1033, refractive index 1.503) as the continuous phase resin; use 7 parts by weight of polystyrene resin (GPPS) (general polystyrene) Resin, manufactured by Daicel Chemical Industries, Ltd.; GPPS#30, refractive index 1.589) as the dispersed phase resin; 1 part by weight of epoxidized diene block copolymer resin (manufactured by Daicel Chemical Industries, Ltd.; Epofriend AT202; Styrene / butadiene = 70 / 30 (weight ratio), epoxy equivalent 750, refractive index about 1.57) as a compatibilizer. The refractive index difference between the continuous phase resin and the dispersed phase resin is 0.086.

[0221] The continuous phase resin and the dispersed phase resin are dried at 70°C for about 4 hours, and the dried resin is kneaded in a closed mixer. In order to obtain a laminated sheet with a three-layer structure (180μm thick), a multi-layer extruder was used to combine the mixture ...

Embodiment 2

[0229] A heat resistance test was performed on an anisotropic scattering sheet made in the same manner as in Example 1, except that the sheet was heat-treated at a temperature of 70°C for 8 hours instead of being heat-treated at a temperature of 90°C for 8 hours.

Embodiment 3

[0231] Further using the roll calendering method (conditions: at a temperature of 125 ℃, the elongation factor is about 2 times (about 1 / 2 of the thickness reduction rate), the width reduction rate is about 3%) uniaxial stretching obtained in Example 1 The anisotropic scattering sheet to obtain a 90μm thick film. Observing the film with TEM (osmic acid coloring), it was found that the shape of the dispersed phase of the intermediate layer resembled a highly stretched fiber, the average length of the long axis was about 30 μm, and the average length of the short axis was about 1.5 μm.

[0232] When the light scattering characteristics of the obtained highly anisotropic uniformly anisotropic scattering sheet were measured by the same method as in Example 1, it was observed that Figure 5 Significant light scattering characteristics shown. In addition, in the light scattering characteristics, Fy(4°) / Fx(4°) is approximately 8.2, Fy(10°) / Fx(10°) is approximately 400, and Fy(30°) / Fx(30°...

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Abstract

An anisotropic scattering sheet comprising at least an anisotropic light scattering layer, wherein the anisotropic light scattering layer comprises a continuous phase and a dispersed phase which are different in refraction index from each other, the mean aspect ratio of the dispersed phase is more than 1, and the major axis directions of each dispersed phase are oriented to a given direction, and wherein the sheet is a heat-treated sheet. In the treatment, the heat-treating temperature may be not less than 70 DEG C, and in the typical treatment, heat-treatment is conducted after the sheet is oriented by a monoaxial stretching through roll calendaring. The present invention ensures to provide an anisotropic scattering sheet stably usable for a long period of time without causing luminance unevenness.

Description

Technical field [0001] The present invention relates to an anisotropic diffusion sheet that is excellent in thermal stability and is used in a display device (flat or flat panel display device) with uniform light emission, a manufacturing method thereof, and a display device using the diffusion sheet. More precisely, the present invention relates to an anisotropic diffusion sheet (diffusion film) that is excellent in thermal stability and is used in a transmissive (transmission type) or reflective (reflection type) liquid crystal display device or a projection television. In addition, the present invention relates to an anisotropic scattering sheet (diffusion film) that is excellent in thermal stability and can limit brightness changes even if the viewing angle to the display surface of the display unit is rotated (or changed), and a method of manufacturing the same, and the use of the sheet的display device. In particular, the present invention relates to such an anisotropic diffus...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G02B5/02G02B1/04G02F1/1335H04N5/74
CPCG02B6/0051G02B5/0231G02B5/0257G02B5/0278Y10T428/254G02B5/0242G02B5/02
Inventor 平石政宪须田聪泉谷辰雄
Owner DAICEL CHEM IND LTD
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