Light diffusing film
View Patent ↗A light diffusing film which is excellent in luminance uniformity and which exhibits no partial deterioration in light transmittance, thereby eliminating the formation of black spots. The light diffusing film, which has a monodisperse light diffuser and a light diffusing layer consisting of a light diffuser and a binder resin on one plane of a base, in which the lamination ratio is 10% or less and the diameter of flocculated particles in the light diffuser is 50 μm or less, exhibits excellent luminance and thermal properties, so that it can be suitably used in various kinds of picture display devices, in particular, in a display device employing LED (light emitting diode) lamps or an LCD (liquid crystal display device) backlight system.
1. A light diffusing film having, on at least one surface of a base film, a light diffusing layer made of an inorganic light diffuser selected from the group consisting of silica, zirconia, calcium carbonate, barium sulfate, glass and titanium dioxide; or organic light diffuser selected from the group consisting of urethane based resins, acryl based resins and vinyl chloride based resins, and a binder resin, wherein a lamination ratio is represented by the Formula 1 and a size of flocculated particles in a laminated light diffuser is represented by the Formula 2, wherein the light diffuser is made of two or more kinds of monodisperse particles, the following Formula 3 is satisfied, wherein an average particle diameter of the light diffuser is in the range of 5 to 50 μm:
Lamination ratio
=
π
×
S
(
µ
m
)
×
Number
of
laminated
particles
in
a
tested
portion
of
the
light
diffuser
480
µ
m
×
480
µ
m
×
100
(
%
)
≤
10
%
,
[
Formula
1
]
Diameter of flocculated particles= S (μm)×Number of flocculated particles in a tested floc and in a tested portion of the light diffuser≦50μm [Formula 2]
wherein S denotes the average particle diameter of the light diffuser,
Sa 1/2 <Sb<Sa [Formula 3]
wherein Sa denotes an average particle diameter of a relatively larger light diffuser particle and Sb denotes an average particle diameter of a relatively smaller diffuser particle.
2. The light diffusing film according to claim 1 , wherein a coating amount of the light diffuser is in the range of 5 to 25 g/m 2 .
3. A display device employing LED (light emitting diode) lamps or an LCD (liquid crystal display) backlight system, and comprising the light diffusing film according to claim 2 .
4. A display device employing LED (light emitting diode) lamps or an LCD (liquid crystal display) backlight system, and comprising the light diffusing film according to claim 1 .