Kimoto Co, Ltd.

Masashi Takai

Toshiaki Ishibashi

Hiroshi Yokota

Yasumaro Toshima

Hideharu Nagami

Kazuya Kitajima

This edge light-type backlight device comprises a light guide plate, a light source disposed at one end part of the light guide plate, a light diffusion sheet and a prism sheet on a light emission face of the light guide plate. The refractive index of the prism sheet exceeds 1.60, a peak of emitted light distribution of the light emission face in a plane parallel to the one end part of the light guide plate and orthogonal to the light emission face is within an angle ranges of 30&#xb0;&#x2dc;45&#xb0; and &#x2212;30&#xb0;&#x2dc;&#x2212;45&#xb0; with respect to a normal direction of the light emission face. The emitted light of the light emission face diminishes toward an emission angle &#x2212;90&#xb0; or 90&#xb0; with respect to the normal line from the angle ranges of the peak of the emitted light distribution. High frontal brightness and diffusion are realized.

Edge light-type backlight device and light diffusion member

There is provided a scattering film that can be used in organic EL light emitting devices and that not only improves efficiency for light utilization and improves viewing angle dependency, which have conventionally been problems, but also can solve the problem of reflection when lights-off. This scattering film for organic EL is used in organic EL light emitting devices. The scattering film comprises a scattering layer that includes a binder resin and particles having a refractive index different from the binder resin. The average particle size of the particles is 10 &#x3bc;m or less, and the coefficient of variation of the average particle size for the particles is 30% or greater.

Scattering film for organic EL and organic EL light emitting device using same

Disclosed is a scattering film which can be used in an organic EL light-emitting device, in which the light utilization efficiency and field-of-view dependence, which have been problems so far in organic EL light-emitting devices, can be improved without interfering the two properties with each other. Specifically disclosed is a scattering film for an organic EL, which can be placed on the light emission surface side of an organic EL light-emitting device for use, and involves a scattering layer, wherein the scattering layer comprises a binder resin, microparticles having a different refractive index from that of the binder resin, and resin particles having a larger average particle diameter than that of the microparticles. The content of the microparticles is preferably 5 to 90 parts by weight relative to 100 parts by weight of the binder resin, and the content of the resin particles is preferably 100 to 300 parts by weight relative to 100 parts by weight of the binder resin.

Scattering film for organic EL, and organic EL light-emitting device equipped with same

A light diffusive sheet of the present invention comprises a transparent polymer sheet provided with a light diffusion layeron one side and an uneven surfacehaving arithmetical mean deviation of 0.5 &#x3bc;m or less and mean spacing of 80 &#x3bc;m or narrower on the opposite side. Such an uneven surface can be made by forming a backcoat layerincluding a mixture of particles having particular mean diameters in a particular proportion to a binder resin on the transparent polymer sheet. An area light source elementof the present invention is produced by laminating a prism sheeton a light guide plateso that the prism surfaceof the prism sheetis opposed to the light-emitting surfaceof the light guide plateand laminating the light diffusive sheet on the prism sheetso that the uneven surface (backcoat layer) of the light diffusive sheet is opposed to the surface opposite of the prism surface. The light diffusive sheet of the present invention can prevent occurrence of a rainbow-like annular pattern without deteriorating the front luminance and view angle of the area light source even when combined with a downward-facing prism sheet.

Growing community of inventors

Saitama, Japan

Masashi Takai