Keiwa Inc.

Tadayoshi Fukuda

Kenichi Harada

Yoshitada Namikawa

Yuki Matsuno

An optical sheet for a backlight unit for guiding toward a front face side rays of light emitted by an LED light source. The optical sheet includes one or more resin layers. Ultrafine grooves oriented in specific directions are provided on a front face side or a back face side of at least one resin layer of the one or more resin layers. An average number of the ultrafine grooves per unit length in a direction perpendicular to an average orientation of the ultrafine grooves is preferably no less than 10/mm and no greater than 10,000/mm. A face of the at least one resin layer provided with the ultrafine grooves preferably has an arithmetic average roughness (Ra) in a direction perpendicular to an orientation of the ultrafine grooves being no less than 0.01 &#x3bc;m and no greater than 5 &#x3bc;m. Ultrafine grooves preferably constitute a diffraction grating.

Optical sheet for backlight unit and backlight unit

Provided is a prism sheet for a backlight unit capable of attaining desired luminance in the front direction, and securing a sufficient viewing angle in the direction perpendicular to the orientation direction of the prism array. The prism sheet comprises one or more resin layers, an outermost resin layer of the one or more resin layers comprising a prism array, wherein on a surface of at least one of the one or more resin layers, micro linear grooves are formed to be parallel to, or to intersect at an acute angle with, an orientation direction of the prism array. An average number of existing micro linear grooves per unit length in a direction perpendicular to an average orientation direction of the micro linear grooves is preferably no less than 30/mm and no greater than 10,000/mm. The micro linear grooves are preferably irregular in length, width or pitch.

Prism sheet for backlight unit and backlight unit for liquid crystal display device

An optical sheet for a liquid crystal display device has functions of condensing rays of light with respect to a specific direction in a plane of the optical sheet, and diffusing rays of light with respect to a direction perpendicular to the specific direction. A backlight unit for a liquid crystal display device includes: a light guide film for guiding rays of light incident on an end face of the light guide film toward a front face side; at least one LED light source disposed along the end face of the light guide film; the optical sheet disposed on the front face side; and a prism sheet disposed on a front face of the optical sheet, with the specific direction being parallel to a direction of rays of light emitted by the at least one LED light source and perpendicular to a direction of prism rows of the prism sheet.

Optical sheet for liquid crystal display device, and backlight unit for liquid crystal display device

An optical sheet for a liquid crystal display device includes a plurality of protruding portions provided scatteredly on a back face, in which the protruding portions each have a flattened semi-spherical shape or a flattened conical shape with a rounded apex. The protruding portions may each have a half spheroidal shape. An occupancy area ratio of the plurality of protruding portions may be no less than 2% and no greater than 80%. An average diameter of the protruding portions may be no less than 5 &#x3bc;m and no greater than 60 &#x3bc;m, and an average height of the protruding portions may be no less than 0.5 &#x3bc;m. A diffraction grating shape with multiple rows that are oriented in a single direction on the back face in a region where the plurality of protruding portions are absent.

Optical sheet for liquid crystal display device, backlight unit for liquid crystal display device and production method of optical sheet for liquid crystal display device

Growing community of inventors

Tokyo, Japan

Tadayoshi Fukuda