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

• Main Authors: MATSUNO YUKI, NAMIKAWA YOSHITADA, HARADA KENICHI, FUKUDA TADAYOSHI
• Format: Patent
• Language: English; Japanese
• Published: 24.11.2017
• Subjects: BLASTING; DEVICES OR ARRANGEMENTS, THE OPTICAL OPERATION OF WHICH ISMODIFIED BY CHANGING THE OPTICAL PROPERTIES OF THE MEDIUM OF THEDEVICES OR ARRANGEMENTS FOR THE CONTROL OF THE INTENSITY,COLOUR, PHASE, POLARISATION OR DIRECTION OF LIGHT, e.g.SWITCHING, GATING, MODULATING OR DEMODULATING; FREQUENCY-CHANGING; FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMSTHEREOF; HEATING; LIGHTING; MECHANICAL ENGINEERING; NON-LINEAR OPTICS; NON-PORTABLE LIGHTING DEVICES; OPTICAL ANALOGUE/DIGITAL CONVERTERS; OPTICAL ELEMENTS, SYSTEMS, OR APPARATUS; OPTICAL LOGIC ELEMENTS; OPTICS; PHYSICS; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHERARTICLES, NOT OTHERWISE PROVIDED FOR; SYSTEMS THEREOF; TECHNIQUES OR PROCEDURES FOR THE OPERATION THEREOF; VEHICLE LIGHTING DEVICES SPECIALLY ADAPTED FOR VEHICLEEXTERIORS; WEAPONS

PROBLEM TO BE SOLVED: To provide an optical sheet capable of preventing sticking as well as preventing scratching on another optical member disposed on a back face side of the sheet.SOLUTION: An optical sheet 1 for a liquid crystal display device includes a plurality of protruding portions 13a, 18a scattered on a back face of the sheet, in which the protruding portions 13a, 18a each have a flattened semi-spherical shape or a flattened conical shape with a rounded apex. Preferably, the protruding portions 13a, 18a are half-split spheroids. An occupancy area ratio of the plurality of protruding portions 13a, 18a is preferably 2% or more and 80% or less. An average diameter of the protruding portions 13a, 18a is preferably 5 μm or more and 60 μm or less, and an average height is preferably 0.5 μm or more. A diffraction grating pattern with multiple rows oriented in one direction is preferably disposed on the back face in a region where the plurality of protruding portions 13a, 18a are absent. The diffraction grating pattern is preferably a pattern resembling scratch marks or hairlines in the one direction. The optical sheet preferably has a diffraction grating pattern also on a back face side of the plurality of protruding portions 13a, 18b, continuing to the above diffraction grating pattern.SELECTED DRAWING: Figure 1 【課題】スティッキングを防止できると共に、裏面側に配設される他の光学部材の傷付きを防止することができる光学シートを提供する。【解決手段】液晶表示装置用光学シート１は、裏面に複数の凸部１３a、１８aを散点的に備え、凸部１３a、１８aが扁平な半球体又は先端部が丸められた扁平な錐体である。凸部１３a、１８aが半割回転楕円体であるとよい。複数の凸部１３a、１８aの占有面積比としては２％以上８０％以下が好ましい。凸部１３a、１８aの平均径としては５μｍ以上６０μｍ以下が好ましく、平均高さとしては０．５μｍ以上が好ましい。裏面のうちの複数の凸部１３a、１８aが存在しない領域に、一方向に配向する多条状の回折格子形状を備えるとよい。回折格子形状が、一方向への擦過痕又はヘアライン状を呈するとよい。複数の凸部１３a、１８aの裏面側にも回折格子形状に連続する回折格子形状を有するとよい。【選択図】図１