BACKLIGHT UNIT AND LIQUID CRYSTAL DISPLAY DEVICE

• Main Authors: DEJIMA HIROHISA, NAMIKAWA YOSHITADA
• Format: Patent
• Language: English; Japanese
• Published: 23.04.2020
• 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; HEATING; LIGHTING; MECHANICAL ENGINEERING; NON-LINEAR OPTICS; NON-PORTABLE LIGHTING DEVICES; OPTICAL ANALOGUE/DIGITAL CONVERTERS; OPTICAL LOGIC ELEMENTS; OPTICS; PHYSICS; SYSTEMS THEREOF; TECHNIQUES OR PROCEDURES FOR THE OPERATION THEREOF; VEHICLE LIGHTING DEVICES SPECIALLY ADAPTED FOR VEHICLEEXTERIORS; WEAPONS

To provide a backlight unit capable of preventing light leakage and warpage of a light diffusion sheet.SOLUTION: A backlight unit 5 includes a prism sheet 24 and a light shielding member 31 for covering a light diffusion sheet 23. When the covering length of the light diffusion sheet 23 before contraction by the light shielding member 31 is represented as A (mm), the thickness of the prism sheet 24 is represented as T (mm), and the contraction amount of the end part 23a on a frame 29 side of the light diffusion sheet 23 in a plane direction of the light diffusion sheet 23 is represented as S (mm), the relationships of the undermentioned formula (1) are established. When a distance between the end part 23a on a frame 30 side of the light diffusion sheet 23 before expansion and the frame 30 is represented as D (mm), and the expansion amount of the end part 23a on the frame side of the light diffusion sheet 23 in a plane direction of the light diffusion sheet 23 is represented as E (mm), the relationships of the undermentioned formula (2) are established. S<2(A-√3T)...(1) E<D...(2)SELECTED DRAWING: Figure 3 【課題】光漏れ及び光拡散シートの撓みを防止するバックライトユニットを提供する。【解決手段】バックライトユニット５は、プリズムシート２４及び光拡散シート２３を被覆する遮光部材３１を備えている。遮光部材３１による収縮前の光拡散シート２３の被覆長さをＡ［ｍｍ］、プリズムシート２４の厚みをＴ［ｍｍ］、光拡散シート２３の平面方向における光拡散シート２３のフレーム２９側の端部２３ａの収縮量をＳ［ｍｍ］とした場合に、以下の式（１）の関係が成立し、膨張前の光拡散シート２３のフレーム３０側の端部２３ａとフレーム３０との距離をＤ［ｍｍ］、光拡散シート２３の平面方向における光拡散シート２３のフレーム側の端部２３ａの膨張量をＥ［ｍｍ］とした場合に、以下の式（２）の関係が成立する。Ｓ＜２（Ａ−√３Ｔ）・・・（１）、Ｅ＜Ｄ・・・（２）【選択図】図３