Light diffuser and use thereof

Patent metadata

Field	Value
Publication number	US-9864110-B2
Application number	US-201415300447-A
Country	US
Kind code	B2
Filing date	Sep 30, 2014
Priority date	Mar 31, 2014
Publication date	Jan 9, 2018
Grant date	Jan 9, 2018

Abstract

A light diffuser and its use are provided, which not only reduces a color change in a source light when the light diffuser is disposed on an optical path of a light source, but also has a good light transmission property and a good light diffusion property. The light diffuser contains a thermoplastic resin and transparent particles added thereto. The total light transmittance of the light diffuser is 75% or more. The degree of dispersion of the light diffuser is 2° or more, the degree of dispersion being defined as a transmission angle at which a light transmittance is 50% of a rectilinear light transmittance when light is emitted to a surface of the light diffuser in a direction normal to the surface. The difference between the rectilinear light transmittance at 460 nm and the rectilinear light transmittance at 580 nm of the light diffuser is 0.96% or less.

First claim

The invention claimed is:

1. A light diffuser which comprises a thermoplastic resin and transparent particles added thereto,
a total light transmittance of the light diffuser being 75% or more,
a degree of dispersion of the light diffuser being 2° or more, wherein the degree of dispersion is defined as a transmission angle at which a light transmittance is 50% of a rectilinear light transmittance when light is emitted to a surface of the light diffuser in a direction normal to the surface, and
a difference between a rectilinear light transmittance at a wavelength of 460 nm and a rectilinear light transmittance at a wavelength of 580 nm of the light diffuser being 0.96% or less,
wherein a number average particle size of the transparent particles is in a range of 1 to 20 μm, and
wherein, provided that a content of particles whose particle size is 0.9 to 1.1 times the number average particle size of the transparent particles is divided by two, a result of which is taken as a first value, and that a content of particles whose particle size is 0.8 to 1.2 times the number average particle size of the transparent particles is divided by four, a result of which is taken as a second value, an absolute value of a difference between the first value and the second value is 1.0% by number or less.

2. The light diffuser according to claim 1 ,
wherein a volume average particle size of the transparent particles is in a range of 1 to 20 μm.

3. The light diffuser according to claim 1 ,
wherein an amount of the transparent particles is in a range of 0.5 to 2.0% by weight.

4. A lighting cover which is a molded product of the light diffuser according to claim 1 .

5. The lighting cover according to claim 4 , which is used for a lighting apparatus for color evaluation.

6. An image projection screen which is a molded product of the light diffuser according to claim 1 .

7. A semi-transparent building material which is a molded product of the light diffuser according to claim 1 .

Assignees

• Sekisui Plastics

Inventors

• Machida Kazuki
• Ishimori Fumitaka

Classifications

• G03B21/62

  Translucent screens · CPC title

• G02B5/0278 Primary

  used in transmission · CPC title

• G02B5/0242

  by means of dispersed particles · CPC title

• F21V3/0445

  Mechanical Engineering · mapped topic

• F21V3/0625

  the material diffusing light, e.g. translucent plastics · CPC title