201040586 六、發明說明： 【發明所屬之技術領域】 本發明係關於防止受傷，於正面方向具有高亮度之光 擴散板，此外，係關於正面方向具有高亮度之高品質的面 光源裝置及液晶顯示裝置。 又，於此說明書及申請專利範圍，「突起部之重心」 一語’思味平面俯視爲約略矩形形狀之突起部的底面之約 Λ 略矩形形狀之一對對角線之交點（交叉點）。 Ο 【先前技術】 作爲液晶顯示裝置，例如具備液晶胞之液晶面板（影 像顯示部）之背面側有面光源裝置被配置作爲背光之構成 係屬公知。作爲前述背光用之面光源裝置，已知者係在燈 箱（lamp box)(筐體）內配置複數光源，同時於這些光 源之前面側配置光擴散板，進而爲了於正面方向確保充分 Q 的亮度而於光擴散板之前面側配置聚光性板之光柵片（ lenticular lens)之構成之面光源裝置。例如，在日本專利 3 1 23 006號說明書（專利文獻1 )，揭示著這樣的構成之 面光源裝置。 然而，在相關於前述構成之面光源裝置，因爲於光擴 散板之前面側爲聚光性板單純重疊的型態，所以會有光擴 散板與聚光性板相互擦滑而容易刮傷的問題。 - 作爲防止這樣的滑擦導致傷痕，於光擴散面之前面側 •中介著黏接劑層配置光柵片之構成之面光源裝置係屬已知 -5- 201040586 (參照日本特開2006-208930號公報（專利文獻2))。 根據此構成的話，因光擴散板與聚光性板係中介著黏接劑 層而被接合，所以光擴散板與聚光性板不會滑擦’可以防 止傷痕產生。 【發明內容】 然而，前述後者之面光源裝置’正面方向之亮度提高 不能夠說是充分大。 本發明之目的在於提供防止受傷’於正面方向具有高 亮度之光擴散板及正面方向具有高亮度之高品質的面光源 裝置與液晶顯示裝置。 爲了達成前述目的，本發明提供以下的手段。 (1 ) 一種光擴散板，係由聚光性板及光擴散性基板 所構成之光擴散板，其特徵爲：該聚光性板具有聚光性透 鏡形成面與聚光性透鏡非形成面，該光擴散性基板之單面 ，被形成複數個突起部，爲相鄰的突起部之間設有凹部之 凹凸形狀面，前述突起部，於平面俯視係具有一對長邊與 一對短邊之約略矩形形狀，前述突起部之底面之長邊的長 度爲〇.8mm〜2.5mm，前述突起部的底面之短邊的長度爲 5 0μπι〜5 00μιη，藉由前述光擴散性基板之凹凸形狀面之突 起部與前述聚光性板之聚光性透鏡非形成面中介著黏接劑 層接合而使前述光擴散性基板與前述聚光性板被層積一體 化，在前述黏接劑層與前述光擴散性基板之凹凸形狀面之 凹部之間被形成空氣層。 -6 - 201040586 (2) 前項1之光擴散板，其中前述複數個突起部， 於長度方向互爲約略平形狀。 (3) 前項2之光擴散板，其中長邊方向相鄰的前述 突起部相互以一定間隔隔開，於短邊方向相鄰的前述突起 部相互以一定間隔隔開。 (4) 前項3之光擴散板，其中相鄰於長邊方向的前 述突起部彼此之重心間距離爲U時，於長邊方向上形成一 列之突起部群之突起部的重心位置，係由對該突起部群構 成在短邊方向上相鄰的鄰接突起部群之複數突起部之中最 近的突起部的重心位置起，於長邊方向離開U/2.2〜U/1.8 之距離。 (5) 前項3或4之光擴散板，其中於長邊方向上相 鄰的前述突起部彼此之重心間距離爲U，前述突起部之底 面之長邊的長度爲T時，成立 1.3^ U/T ^2.2 之關係式，短邊方向上相鄰的前述突起部彼此之重心 間距離爲F，前述突起部之底面之短邊長度爲L時，F爲 400μιη以上5.0mm以下，成立[Technical Field] The present invention relates to a light diffusing plate having high brightness in the front direction for preventing injury, and a high-quality surface light source device and liquid crystal display having high brightness in the front direction. Device. Further, in the scope of the specification and the patent application, the term "center of gravity of the protrusion" is a view of the intersection of the diagonally opposite one of the approximately rectangular shape of the bottom surface of the protrusion of the approximately rectangular shape in plan view (intersection). . [Prior Art] As the liquid crystal display device, for example, a surface light source device having a liquid crystal panel (image display unit) on the back side of the liquid crystal display device is disposed as a backlight. As a surface light source device for backlights, it is known that a plurality of light sources are disposed in a lamp box (housing), and a light diffusing plate is disposed on the front side of the light sources, and a sufficient Q brightness is secured in the front direction. On the front side of the light diffusing plate, a surface light source device having a lenticular lens of a light-concentrating plate is disposed. For example, a surface light source device of such a configuration is disclosed in the specification of Japanese Patent No. 3 1 23 006 (Patent Document 1). However, in the surface light source device according to the above configuration, since the front surface side of the light diffusing plate is a form in which the condensing plate is simply overlapped, the light diffusing plate and the condensing plate are rubbed against each other and are easily scratched. problem. - As a surface light source device which is configured to prevent the scratches from being caused by such a slip, and which is disposed on the front side of the light-diffusing surface and in which the lenticular sheet is disposed in the adhesive layer, is known as -5 - 201040586 (refer to JP-A-2006-208930) Bulletin (Patent Document 2)). According to this configuration, since the light diffusing plate and the condensing plate are bonded to each other via the adhesive layer, the light diffusing plate and the condensing plate are not rubbed to prevent the occurrence of scratches. SUMMARY OF THE INVENTION However, the brightness improvement in the front direction of the latter surface light source device 's cannot be said to be sufficiently large. SUMMARY OF THE INVENTION An object of the present invention is to provide a surface light source device and a liquid crystal display device which are capable of preventing damage from being caused by a light diffusing plate having high luminance in the front direction and having high luminance in the front direction. In order to achieve the aforementioned objects, the present invention provides the following means. (1) A light diffusing plate comprising a light diffusing plate and a light diffusing substrate, wherein the light collecting plate has a condensing lens forming surface and a condensing lens non-forming surface a plurality of protrusions are formed on one surface of the light-diffusing substrate, and a concave-convex surface having a concave portion is provided between adjacent protrusions, and the protrusion has a pair of long sides and a pair of short sides in plan view. The side has a substantially rectangular shape, and the length of the long side of the bottom surface of the protrusion is 〇.8 mm to 2.5 mm, and the length of the short side of the bottom surface of the protrusion is 50 μm to 50,000 μm, and the unevenness of the light diffusing substrate The protruding portion of the shape surface is bonded to the non-forming surface of the condensing lens of the concentrating sheet via an adhesive layer, and the light diffusing substrate and the condensing sheet are laminated and integrated. An air layer is formed between the layer and the concave portion of the uneven surface of the light diffusing substrate. -6 - 201040586 (2) The light diffusing plate of item 1, wherein the plurality of protrusions are approximately flat in shape in the longitudinal direction. (3) The light-diffusing sheet of the second aspect, wherein the projections adjacent to each other in the longitudinal direction are spaced apart from each other at a predetermined interval, and the projections adjacent to each other in the short-side direction are spaced apart from each other by a predetermined interval. (4) The light-diffusing sheet of the item 3, wherein, when the distance between the centers of gravity of the protrusions adjacent to the longitudinal direction is U, the position of the center of gravity of the protrusions forming the row of the protrusions in the longitudinal direction is The projection group includes the center of gravity of the nearest projection among the plurality of projections of the adjacent projections adjacent in the short-side direction, and is separated from the U/2.2 to U/1.8 in the longitudinal direction. (5) The light diffusing plate according to Item 3 or 4, wherein a distance between the centers of gravity of the protrusions adjacent to each other in the longitudinal direction is U, and when the length of the long side of the bottom surface of the protrusion is T, 1.3 ^ U is established. In the relationship of /T ^2.2 , the distance between the centers of gravity of the adjacent protrusions in the short-side direction is F, and when the length of the short side of the bottom surface of the protrusion is L, F is 400 μm or more and 5.0 mm or less.
8.0 ^ F/L 之關係式。 (6) —種面光源裝置，具備：前項〗〜5之任一項之 光擴散板’及被配置於該光擴散板的背面側之複數光源， 以前述聚光性板成爲前面側的方式配置前述光擴散板。 (7 ) —種液晶顯示裝置，具備：前項1〜5之任一項 201040586 之光擴散板，及被配置於該光擴散板的背面側之 ，及被配置於前述光擴散板的前面側之液晶面板 聚光性板成爲前面側的方式配置前述光擴散板。 在（1 )之發明，光擴散性基板之凹凸形狀 部與聚光性板之聚光性透鏡未被形成之面係中介 層而被接合，所以光擴散性基板與聚光性板不會 止此光擴散板之傷痕產生。此外，黏接劑層與光 板之凹凸形狀面之凹部之間存在空氣層，所以正 得高亮度。此外，被形成於光擴散性基板的表面 突起部，於平面俯視長邊長度爲0.8mm〜2.5mm 度爲 50μηι〜500μιη之約略矩形形狀，所以可避 起部對此光擴散板之光學功能造成影響也可迴避 像之畫質造成影響。進而，前述空氣層，可以僅 著黏接劑層而層積於單面具備前述特定的凹凸形 擴散性基板與聚光性板，層積時光擴散性基板之 揮間隔件的作用而可以確保空氣層，所以生產性 在（2)之發明，複數個突起部，於長度方 互約略平行狀，所以於突起部之長度方向可確保 合強度’沿著突起部的長度方向要剝離光擴散性 光性板是困難的。 在（3 )之發明，長邊方向相鄰的突起部係 定間隔隔開，於短邊方向相鄰的突起部相互以一 開’所以可避免這些突起部對此光擴散板之光學 響’可更能迴避對顯示影像的畫質之影響。 複數光源 ;以前述 面之突起 著黏接劑 滑擦，防 擴散性基 面方向可 之複數個 而短邊長 免這些突 對顯示影 藉由中介 狀面的光 突起部發 優異。 向，爲相 充分的接 基板與聚 相互以一 定間隔隔 功能的影 -8- 201040586 . 在（4)之發明，相鄰於長邊方向的前述突起部彼此 之重心間距離爲u時，於長邊方向上形成一列之突起部群 之突起部的重心位置，係由對該突起部群構成在短邊方向 上相鄰的鄰接突起部群之複數突起部之中最近的突起部的 重心位置起，於長邊方向離開（偏離）υ/2·2〜u/1.8之距 離，所以長邊方向上相鄰的突起部彼此之間隔或短邊方向 上相鄰的突起部彼此之間隔爲很大的構成’也可以防止聚 _ 光性板撓曲而該聚光性板接觸或接近光擴散性基板的凹凸 〇 形狀面之凹部，藉此可確保充分的空氣層，可使正面方向 之亮度進而提高。 在（5)之發明，於長邊方向上相鄰的突起部彼此之 重心間距離爲U，突起部之底面之長邊的長度爲T時，成 立1.3 S U/TS 2.2之關係式，所以防止聚光性板撓曲而該 聚光性板接觸或接近於光擴散性基板的凹凸形狀面的凹部 ，藉此確保充分的空氣層，所以可進而提升正面方向的亮 Q 度，同時，短邊方向上相鄰的突起部彼此之重心間距離爲 F，突起部之底面之短邊長度爲L時，F爲400 μπι以上 5.0mm以下，成立8.0 S F/L之關係式，所以被形成於黏接 劑層與光擴散性基板的凹凸形狀面的凹部之間的空氣層之 空隙於短邊方向可以擴展，能夠以更高的透過率使光透過 ，所以可以更爲增大正面方向之亮度。 在（6)之發明，提供防止光擴散板之傷痕，可得正 - 面方向之亮度高的高品質的光之面光源裝置。 在（7)之發明，提供防止光擴散板之傷痕，可得正 -9 - 201040586 面方向之亮度高的高品質的影像之液晶顯示裝置。 【實施方式】 相關於本發明之液晶顯示裝置之一實施型態顯示於圖 1。於圖1 ’ （ 3 0 )係液晶顯示裝置，（1丨）爲液晶胞，（ 12) (13)爲偏光板’ （1)爲面光源裝置（背光）。於 前述液晶胞（1 1 )之上下兩側分別被配置偏光板（1 2 )( 1 3 )，藉由這些構成構件（1 1 ) ( 1 2 ) ( 1 3 )構成作爲影 像顯示部之液晶面板（2 0 )。又，作爲前述液晶胞（丨i ) ，以使用可顯示彩色影像者爲佳。 前述面光源裝置（1 ) ’被配置於前述液晶面板（20 )的下側之偏光板（1 3 )之下面側（背面側）。亦即，此 液晶顯示裝置（30 )，爲直下型液晶顯示裝置。 前述面光源裝置（1 )具備：平面俯視爲矩形狀上面 側（前面側）開放之薄箱型形狀之燈箱（5 )、在該燈箱 (5 )內相互隔開配置的複數光源（2 )、被配置在這些複 數光源（2 )之上方側（前面側）的光擴散板（3 )。前述 光擴散板（3 )係對前述燈箱（5 )以塞住開放面的方式被 載置而固定。此外，前述燈箱（5 )之內面設有光反射層 (未圖示）。在本實施型態，作爲前述光源（2 )使用冷 陰極線燈管等線狀光源。 前述光擴散板（3 )，如圖2所示，具備相互被配置 爲平行狀之光擴散性基板（3 1 )、聚光性板（4 1 )及黏接 劑層（40 )。前述光擴散性基板（3 1 )，於表面被形成多 -10- 201040586 • 數個突起部（32)，同時於單面具有在相鄰的突起部（32 )之間設有凹部（在本實施型態爲平坦部）（33)之凹凸 形狀面（34 )(參照圖3 )。此光擴散性基板（3 1 )之凹 凸形狀面（34 )之突起部（32 )與前述聚光性板（41 )之 聚光性透鏡非形成面（未被形成聚光性透鏡之側之面）中 介著黏接劑層（40)而被黏接，藉此，在前述黏接劑層（ 40 )與前述光擴散性基板（3 1)之凹凸形狀面（34 )之凹 0 部（3 3 )之間存在空氣層（42 )的狀態下使前述光擴散性 基板（3 1 )與前述聚光性板（4 1 )被層積一體化（參照圖 2)。又，前述黏接劑層（40)係於前述聚光性板（41) 之單面之約略全面無間隙地被層積。 前述突起部（32)於平面俯視爲具有一對長邊（35) (3 5 )與一對短邊（3 6 )( 3 6 )之約略矩形形狀（參照圖 4 )。前述突起部（3 2 )之底面（連接於光擴散性基板之 面）之長邊的長度（T)被設定爲〇.8mm〜2.5mm，前述突 Q 起部（3 2 )的底面（連接於光擴散性基板之面）之短邊的 長度（L)被設定爲50μιη〜500μχη。 如圖4所示’這些多數個突起部（32 )，於平面俯視 跨全體被配置爲散開狀態。多數個突起部（32)於平面俯 視被配置爲之字形。在本實施型態，長邊方向相鄰的突起 部（32 )相互以一定間隔隔開配置，於短邊方向相鄰的突 起部（3 2 )相互以一定間隔隔開配置（參照圖4)。又， 長邊方向之一定之隔開間隔，與短邊方向之一定之隔開間 ' 隔，可以不同，亦可相同。 -11 - 201040586 在本實施型態，前述突起部（3 2 )之剖面形狀 半圓形狀（參照圖2、3 )。亦即，在本實施型態， 起部（32)係由柱狀（cylindrical)透鏡形狀之突 約略半圓柱狀之突條部）所構成，這些複數之柱狀 狀之突條部（3 2 )，於長度方向（軸線方向），係 約略平行狀的方式被配置（參照圖4 )。前述柱狀 狀’係相當於使約略圓柱體以平行於其軸線方向（ 向）的平面（亦可爲包含軸線的平面，亦可爲不含 平面）切開後之任一方的構件的形狀。 在本實施型態，前述柱狀透鏡形狀之突條部（ 爲半圓柱形狀所構成之突條部，亦即具備相當於將 以包含其軸線的平面均等切爲2個之中的任一方之 半圓柱體）的形狀之突條部。由此半圓柱形狀所構 條部（3 2 )的平面（切斷面）連接於前述光擴散性 3 1 )的表面（參照圖2、3 )。由前述半圓柱形狀所 突條部（3 2 )的圓弧面以朝向前述聚光性板（4 1 ) 的方式被配置（參照圖2)。 在本實施型態，作爲前述光源（2 )使用線狀 以此線狀光源（2 )之長度方向與前述光擴散性基 )的柱狀透鏡形狀之突條部（3 2 )的長度方向（長 )成爲約略一致的方式被配置。此外，前述柱狀透 的突條部（32)的長度方向（長邊方向）係以與前 散板（3 )的長邊方向約略一致的方式被配置。 於前述液晶顯示裝置（3 0 )，前述光擴散板 爲約略 前述突 條部（ 透鏡形 以互爲 透鏡形 長度方 軸線的 32 )， 圓柱體 構件（ 成的突 基板（ 構成的 側突出 光源， 板（31 邊方向 鏡形狀 述光擴 -12- (3 )， 201040586 係以其聚光性板（4 1 )位於前面側（液晶面板（2〇 )側） 的方式被配置（參照圖1)。亦即，換句話說，於前述液 晶顯示裝置（3 0 )，前述光擴散板（3 )，係以其光擴散 性基板（3 1 )成爲背面側（光源（2 )側）的方式被配置 (參照圖1 )。 相關於前述構成之光擴散板（3 )，係光擴散性基板 (3 1 )之凹凸形狀面（34 )之突起部（32 )與聚光性板（ 41)之聚光性透鏡未被形成之面中介著黏接劑層（40)而 被接合，所以光擴散性基板（3 1 )與聚光性板（4 1 )不會 滑擦，防止此光擴散板（3 )之傷痕產生。此外，相關於 前述構成之光擴散板（3 )，在黏接劑層（40 )與光擴散 性基板（3 1 )之凹凸形狀面（3 4 )之凹部（平坦部）（3 3 )之間存在空氣層（42)，所以於前述面光源裝置（1) 可以對正面方向（法線方向）（Q )以高亮度進行照明， 可以於前述液晶顯示裝置（30)往正面方向（法線方向） (Q)以高亮度顯示影像。進而，於平面俯視長邊長度（T )爲 0.8mm〜2.5mm，而短邊長度（L)爲 50μηι〜500μηι 之約略矩形形狀的突起部（3 2 )被形成於光擴散性基板（ 3 1 )的表面，所以可避免該突起部（3 2 )對此光擴散板（ 3)之光學功能造成不良影響，可顯示具備高品質的畫質 之影像。 於本發明，前述突起部（32)的底面之長邊長（Τ) 爲0.8mm〜2.5mm。該長度（Τ)太短的話於突起部（32) 的成形性會發生問題，太長的話通過液晶面板會被看到突 -13- 201040586 起部（3 2 )使影像的品質降低。 此外，前述突起部（32)的底面之短邊長（L) % 〜500μιη。該長度（L)太短的話’要製作精度佳的 是困難的，太長的話突起部（3 2 )的形狀會成爲紋理 而有被看到之虞。 於本發明，相鄰於長邊方向的突起部（32)彼此 心（G )間距離爲U時，於長邊方向上形成一列之突 群之突起部（3 2 )的重心位置（G 1 )，係由對該突起 構成在短邊方向上相鄰的鄰接突起部群之複數突起部 最近的突起部（32 )的重心位置（G2 )起，於長邊方 開（偏移）U/2.2〜U/1.8之距離爲較佳（參照圖4 ) 即，於圖4，最好是成立K = U/2.2〜U/1.8之關係式 成。採用此構成的場合，即使長邊方向上相鄰的突起 32)彼此之間隔或短邊方向上相鄰的突起部（32)彼 間隔爲很大的構成，也可以防止聚光性板（4 1 )撓曲 聚光性板（4 1 )接觸或接近光擴散性基板（3 1 )的凹 狀面（34)之凹部（33)，藉此可確保充分的空氣層 )，所以可使正面方向之亮度更爲提高。 此外，於長邊方向相鄰的突起部（32)彼此的重 G)間距離爲U，突起部（32)的底面之長邊（35) 度爲Τ時，成立 1.3^ U/T ^2.2 之關係式的構成爲較佳（參照圖4 )。採用此構 場合’藉由1.3SU/T可以確保充分的空氣層（42) b 50 形狀 那樣 之重 起部 部群 之中 向離 。亦 之構 部（ 此之 而該 凸形 (42 心（ 的長 成的 ，同 -14- 201040586 . 時藉由U/TS2.2可以防止聚光性板（41)之撓曲。 此外，於短邊方向相鄰的突起部（32 )彼此的重心（ G)間距離爲F，突起部（32)的底面之短邊（36)的長 度爲L時，成立 400μηι^ 5.0mm8.0 ^ F / L relationship. (6) A surface light source device comprising: the light diffusing plate of any one of the above items to 5; and a plurality of light sources disposed on a back side of the light diffusing plate, wherein the light collecting plate is on the front side The aforementioned light diffusing plate is disposed. (7) A liquid crystal display device comprising: the light diffusing plate of any of the above items 1 to 5, 201040586, disposed on a back side of the light diffusing plate, and disposed on a front side of the light diffusing plate The light diffusing plate is disposed such that the liquid crystal panel concentrating plate is on the front side. In the invention of (1), the uneven portion of the light-diffusing substrate and the surface on which the condensing lens of the concentrating sheet are not formed are bonded to each other, so that the light-diffusing substrate and the condensing sheet do not stop. The scratch of the light diffusing plate is generated. Further, since there is an air layer between the adhesive layer and the concave portion of the uneven surface of the light plate, high brightness is obtained. Further, the surface protrusion portion formed on the light-diffusing substrate has a substantially rectangular shape in which the length of the long side of the plane is 0.8 mm to 2.5 mm and the degree is 50 μm to 500 μm, so that the optical function of the light diffusing plate can be avoided. The effect can also be avoided by the image quality. Further, the air layer may be provided on the single surface by the adhesive layer alone, and may have the specific uneven-shaped diffusing substrate and the condensing plate on one surface, and the spacer of the light-diffusing substrate at the time of lamination may ensure air. In the invention of (2), the plurality of protrusions are substantially parallel to each other in the longitudinal direction, so that the joint strength can be ensured in the longitudinal direction of the protrusion portion. The light diffusing light is to be peeled off along the longitudinal direction of the protrusion portion. Sex board is difficult. In the invention of (3), the protrusions adjacent to each other in the longitudinal direction are spaced apart from each other, and the protrusions adjacent to each other in the short side direction are opened one by one, so that the optical sound of the protrusions to the light diffusion plate can be avoided. It can more avoid the influence on the image quality of the displayed image. The plurality of light sources are slid by the adhesive on the surface, and the anti-diffusion base can be plural in number and the short sides are long. These images are excellent in the light-emitting portions of the intervening surface. In the invention of (4), when the distance between the centers of gravity of the protrusions adjacent to the longitudinal direction is u, The position of the center of gravity of the protrusion portion forming the row of the protrusion groups in the longitudinal direction is the position of the center of gravity of the most recent protrusion among the plurality of protrusions of the adjacent protrusion group adjacent to each other in the short side direction. Since the distance from the υ/2·2 to u/1.8 is separated (deviation) in the longitudinal direction, the distance between the adjacent protrusions in the longitudinal direction or the protrusions adjacent in the short side direction is very different from each other. The large configuration 'can also prevent the poly-light plate from being deflected and the concentrating plate is in contact with or close to the concave portion of the concave-convex shape surface of the light-diffusing substrate, thereby ensuring a sufficient air layer and enabling brightness in the front direction Further improve. In the invention of (5), the distance between the centers of gravity of the adjacent protrusions in the longitudinal direction is U, and when the length of the long side of the bottom surface of the protrusion is T, the relationship of 1.3 SU/TS 2.2 is established, so that it is prevented. When the concentrating plate is deflected and the condensing plate is in contact with or close to the concave portion of the uneven surface of the light diffusing substrate, thereby ensuring a sufficient air layer, the bright Q degree in the front direction can be further enhanced, and at the same time, the short side When the distance between the centers of gravity of the adjacent protrusions in the direction is F, and the length of the short side of the bottom surface of the protrusion is L, F is 400 μπι or more and 5.0 mm or less, and the relationship of 8.0 SF/L is established, so that it is formed in the viscosity. The gap between the adhesive layer and the concave portion of the uneven surface of the light-diffusing substrate can be expanded in the short-side direction, and light can be transmitted at a higher transmittance, so that the brightness in the front direction can be further increased. According to the invention of (6), it is possible to provide a high-quality light surface light source device which can prevent scratches of the light diffusing plate and which has high brightness in the normal direction. According to the invention of (7), it is possible to provide a high-quality image liquid crystal display device which is capable of obtaining a high-quality image having a high brightness in the plane direction of -9 - 201040586. [Embodiment] An embodiment of a liquid crystal display device according to the present invention is shown in Fig. 1. In Fig. 1' (30) liquid crystal display device, (1) is a liquid crystal cell, and (12) and (13) are polarizing plates' (1) being a surface light source device (backlight). A polarizing plate (1 2 ) (1 3 ) is disposed on each of the upper and lower sides of the liquid crystal cell (1 1 ), and the constituent members (1 1 ) ( 1 2 ) ( 1 3 ) constitute a liquid crystal as an image display portion. Panel (2 0 ). Further, as the liquid crystal cell (丨i), it is preferable to use a displayable color image. The surface light source device (1)' is disposed on the lower surface side (back surface side) of the polarizing plate (13) on the lower side of the liquid crystal panel (20). That is, the liquid crystal display device (30) is a direct type liquid crystal display device. The surface light source device (1) includes a thin box-shaped light box (5) having a rectangular top surface (front side) in plan view, and a plurality of light sources (2) disposed apart from each other in the light box (5), A light diffusing plate (3) disposed on the upper side (front side) of the plurality of light sources (2). The light diffusing plate (3) is placed and fixed to the light box (5) so as to close the open surface. Further, a light reflecting layer (not shown) is provided on the inner surface of the light box (5). In the present embodiment, a linear light source such as a cold cathode line lamp is used as the light source (2). As shown in Fig. 2, the light diffusing plate (3) includes a light diffusing substrate (31), a condensing plate (41), and an adhesive layer (40) which are arranged in parallel with each other. The light diffusing substrate (3 1 ) is formed on the surface by a plurality of 10-201040586 • a plurality of protrusions (32), and has a concave portion between adjacent protrusions (32) on one side (in this case) The concave-convex shape surface (34) of the flat portion (33) is implemented (see Fig. 3). The protrusion (32) of the uneven surface (34) of the light diffusing substrate (31) and the condensing lens non-forming surface of the condensing sheet (41) (the side where the condensing lens is not formed) The surface of the adhesive layer (40) is bonded to the adhesive layer (40), thereby forming a concave portion of the concave-convex surface (34) of the adhesive layer (40) and the light-diffusing substrate (31) ( 3 3) The light-diffusing substrate (31) and the light-concentrating plate (4 1 ) are laminated and integrated in a state where the air layer (42) is present (see Fig. 2). Further, the adhesive layer (40) is laminated on a single surface of the light-concentrating plate (41) with a substantially uniform gap. The protrusion (32) has a substantially rectangular shape in a plan view of a pair of long sides (35) (35) and a pair of short sides (36) (36) (see Fig. 4). The length (T) of the long side of the bottom surface (surface connected to the light diffusing substrate) of the protruding portion (32) is set to 〇8 mm to 2.5 mm, and the bottom surface of the protruding portion (3 2 ) is connected The length (L) of the short side of the surface of the light-diffusing substrate is set to 50 μm to 500 μm. As shown in Fig. 4, the plurality of projections (32) are arranged in a dispersing state across the entire plan view. A plurality of protrusions (32) are arranged in a zigzag shape in a plan view. In the present embodiment, the projections (32) adjacent to each other in the longitudinal direction are arranged at a constant interval, and the projections (3 2 ) adjacent to each other in the short-side direction are arranged at a constant interval (see FIG. 4). . Further, the interval between the longitudinal direction and the space in the short side direction may be different or different. -11 - 201040586 In this embodiment, the cross-sectional shape of the protrusion (32) is a semicircular shape (see Figs. 2 and 3). That is, in the present embodiment, the starting portion (32) is constituted by a bulging portion of a cylindrical lens shape which is approximately semi-cylindrical, and the plurality of columnar ridge portions (3 2 In the longitudinal direction (axial direction), they are arranged in a substantially parallel manner (see Fig. 4). The columnar shape corresponds to a shape of a member in which a substantially cylindrical body is cut in a plane parallel to the axial direction (or a plane of the axis (which may be a plane including the axis or may be a plane free). In the present embodiment, the lenticular portion of the lenticular lens shape (the ridge portion formed by the semi-cylindrical shape, that is, the slanting portion corresponding to the plane including the axis thereof is equally cut into two The ridge portion of the shape of the semi-cylindrical body. The plane (cut surface) of the strip portion (32) of the semi-cylindrical shape is connected to the surface of the light diffusing property 3 1 (see Figs. 2 and 3). The arcuate surface of the ridge portion (32) of the semi-cylindrical shape is disposed so as to face the condensing plate (4 1 ) (see Fig. 2). In the present embodiment, as the light source (2), the longitudinal direction of the lenticular portion (3 2 ) of the lenticular lens shape in which the longitudinal direction of the linear light source (2) and the light diffusing group are linearly used is used ( Long) is configured in a roughly consistent manner. Further, the longitudinal direction (longitudinal direction) of the columnar ridge portion (32) is arranged to substantially coincide with the longitudinal direction of the front diffuser (3). In the liquid crystal display device (30), the light diffusing plate is about the ridge portion (the lens shape is 32 which is a lenticular length square axis), and the cylindrical member (the formed protruding substrate (the formed side protruding light source, The plate (31 side direction mirror shape light expansion -12- (3), 201040586 is arranged such that its concentrating plate (4 1 ) is located on the front side (the liquid crystal panel (2 〇) side) (refer to Fig. 1) In other words, in the liquid crystal display device (30), the light diffusing plate (3) is formed such that the light diffusing substrate (31) is on the back side (light source (2) side). Arrangement (see Fig. 1) The light diffusing plate (3) having the above-described configuration is a projection (32) and a condensing plate (41) of the uneven surface (34) of the light diffusing substrate (31). Since the surface of the condensing lens that is not formed is bonded via the adhesive layer (40), the light diffusing substrate (31) and the condensing plate (4 1 ) are not slipped, and the light diffusing plate is prevented. (3) the occurrence of a flaw. Further, in relation to the light diffusing plate (3) of the foregoing configuration, in the adhesive layer (40) and The air layer (42) exists between the concave portions (flat portions) (3 3 ) of the uneven surface (3 4 ) of the diffusing substrate (3 1 ), so that the surface light source device (1) can face the front direction (normal) The direction () is illuminated with high brightness, and the image can be displayed with high brightness in the front direction (normal direction) (Q) of the liquid crystal display device (30). Further, the length of the long side (T) in the plan view is 0.8. The protrusion (3 2 ) having an approximately rectangular shape with a short side length (L) of 50 μm to 500 μm is formed on the surface of the light diffusing substrate ( 3 1 ), so that the protrusion can be avoided (3 2 ) In the present invention, the long side length (Τ) of the bottom surface of the protrusion (32) is 0.8 mm. 2.5mm. If the length (Τ) is too short, the formability of the protrusion (32) may cause a problem. If the length is too long, the liquid crystal panel will be seen. The protrusion (13) will reduce the image quality. Further, the short side of the bottom surface of the protrusion (32) is long (L) % to 500 μm If the length (L) is too short, it is difficult to make the precision. If the length is too long, the shape of the protrusion (3 2 ) will become a texture and be seen. In the present invention, adjacent to the long side. When the distance between the protrusions (32) in the direction is U, the position of the center of gravity (G 1 ) of the protrusions (3 2 ) of the protrusions in the longitudinal direction is formed by the protrusions. The distance from the center of gravity (G2) of the nearest protrusion (32) of the plurality of protrusions adjacent to each other in the short-side direction is the distance of the long side (offset) U/2.2 to U/1.8. Preferably (see Fig. 4) That is, in Fig. 4, it is preferable to establish a relational expression of K = U/2.2 to U/1.8. According to this configuration, even if the projections 32) adjacent to each other in the longitudinal direction are spaced apart from each other or the projections (32) adjacent in the short-side direction are spaced apart from each other, the condensing sheet can be prevented (4). 1) The deflection concentrating plate (4 1 ) contacts or approaches the concave portion (33) of the concave surface (34) of the light diffusing substrate (31), thereby ensuring a sufficient air layer), so that the front surface can be made The brightness of the direction is further improved. Further, the distance between the weights G) of the protrusions (32) adjacent to each other in the longitudinal direction is U, and when the long side (35) of the bottom surface of the protrusion (32) is Τ, 1.3^ U/T ^2.2 is established. The configuration of the relational expression is preferable (refer to Fig. 4). With this configuration, by 1.3SU/T, it is possible to ensure a sufficient air layer (42) b 50 shape like the center of the lift portion. Also the configuration (the convex shape (42 hearts (of the same, -14-201040586. By U/TS2.2 can prevent the deflection of the concentrating plate (41). In addition, The distance between the centers of gravity (G) of the protrusions (32) adjacent in the short-side direction is F, and the length of the short side (36) of the bottom surface of the protrusion (32) is L, and 400 μηι ^ 5.0 mm is established.
8.0$ F/L 之二關係式的構成爲較佳（參照圖4)。採用此構成 β 的場合，可以使被形成於黏接劑層（40 )與光擴散性基板 0 (31)之凹凸形狀面（34)的凹部（33)之間的空氣層（ 42 )的空隙於短邊方向擴展，能夠以更高的透過率使光透 過，所以可進而增大正面方向的亮度。 亦即，藉由使F爲4〇〇μηι以上，可以使空氣層（42 ) 充分形成於黏接劑層（40 )與光擴散性基板（3 1 )之凹凸 形狀面（34)的凹部（33)之間，同時藉由使F爲5.0mm 以下，可以防止聚光性板（4 1 )撓曲而該聚光性板（4 1 ) Ο 接觸或接近光擴散性基板（3 1 )的凹凸形狀面（34 )的凹 部（3 3 )。此外’藉著成立8 · 0 S F/L之關係式，可以使 空氣層（42 )之空隙於短邊方向擴展，能夠以更高的透過 率使光透過，所以可進而增大正面方向之亮度。 於本發明，作爲前述光擴散性基板（3 1 )，只要是能 使透過光擴散者都可以使用’其中以在透明材料中分散光 擴散粒子（光擴散劑）之板較適於使用。 作爲前述光擴散性基板（3 1 )，並沒有特別限定的， 例如可以使用由透明樹脂構成的單層板、由透明樹脂構成 -15- 201040586 的基層之至少單面上被層積不同種的透明樹脂所構成的1 或是複數之其他層之層積板等。 作爲構成前述光擴散性基板（3 1 )的透明材料，並沒 有特別限制，例如可以舉出透明樹脂、無機玻璃等。作爲 目IJ述透明樹脂’以容易成形這一點來看’最好使用透明熱 塑性樹脂。作爲此透明熱塑性樹脂，雖無特別限定，但例 如可舉出聚碳酸酯樹脂、ABS樹脂（丙烯腈-苯乙烯-丁二 烯共聚物樹脂）、甲基丙烯酸樹脂' MS樹脂（甲基丙嫌 酸甲酯（MMA)-苯乙烯共聚物樹脂）、聚苯乙烯樹脂、 AS樹脂（丙烯腈-苯乙嫌共聚物樹脂）、聚對苯二甲酸乙 二酯、烯烴樹脂（聚乙烯、聚丙烯、環狀聚烯烴、環狀嫌 烴共聚合體等）等等。 作爲前述光擴散粒子，只要與構成光擴散性基板（3 i )的透明材料爲非相溶性且與此透明樹脂之折射率不同的 粒子可以擴散透過光者即可沒有特別限定，任何東西都可 以使用。例如，亦可以使用氧化矽粒子、碳酸鈣粒子、硫 酸鋇粒子、氧化鈦粒子、氫氧化鋁粒子、無機玻璃粒子、 雲母粒子、滑石粒子、白碳墨粒子、氧化鎂粒子、氧化鋅 粒子等無機粒子，或者亦可以使用甲基丙烯酸系架橋樹脂 粒子、甲基丙烯酸系高分子量樹脂粒子、苯乙烯系架橋樹 脂粒子、系高分子量樹脂粒子、砂氧院系聚合體粒子等有 機粒子。作爲前述光擴散粒子，可以使用一種前述例示者 ’亦可混合使用這些之二種以上。 作爲前述光擴散粒子，通常使用其體積平均粒徑爲 -16- 201040586 0.1 μηι〜50μηι者。又，體積平均粒徑（d5q )，係測定全 粒子之粒徑及體積，由小粒徑者開始依序積算體積，該積 算體積對全粒子之合計體積爲5 0 %的粒子之粒徑。 前述光擴散粒子之使用量，隨著目的之透過光的擴散 程度而有所不同’通常，對前述透明材料1〇〇質量份之光 擴散粒子的含量爲0.01質量份〜20質量份。光擴散粒子 在前述透明材料100質量份中之含量以〇」質量份〜10質 量份爲較佳。 從光擴散性的觀點來看，前述透明材料之折射率與前 述光擴散粒子之折射率之差的絕對値爲〇.〇2以上較佳， 由光透過性的觀點來看，前述絕對値以在〇. 1 3以下爲較 佳。亦即，前述透明材料之折射率與前述光擴散粒子的折 射率之差的絕對値最好在0·〇2〜0.13的範圍。 於前述光擴散性基板（3 1 )例如亦可含有紫外線吸收 劑、熱安定劑、防氧化劑、耐天候劑、光安定劑、螢光增 白劑、加工安定劑等各種添加劑。 前述光擴散性基板（31)的厚度（Ν)，通常爲 0 . 1 mm 〜1 0mm。 前述突起部（3 2 )之剖面形狀並無特別限定，例如除 了約略半圓形狀以外，還可以舉出約略半橢圓形狀、扁平 彎曲線形狀、或約略矩形形狀、約略三角形形狀等約略多 角形狀等。 又，在前述實施型態，前述突起部（3 2 )的剖面形狀 爲半圓形狀，對通過此圓的中心之法線（對水平面垂直之 -17- 201040586 線）形成爲左右線對稱之剖面形狀，但不限定要是 構成’亦可被形成爲左右非線對稱之剖面形狀。例 以是左側的圓弧比右側的圓弧更膨出至前面側之左 對稱之剖面形狀。此外，作爲前述突起部（3 2 )的 狀採用三角形形狀的場合，亦可爲左右線對稱之二 角形形狀，或者是左右爲非線對稱的三角形形狀。 作爲前述突起部（3 2 )之形成手法並無特別限 如可以舉出根據模具之熱轉印法、射出成形法、切 異模壓出成形法、根據雕刻輥之融溶壓出轉印成形之 前述突起部（32)的高度（H)最好爲ΙΟμηι〜 (參照圖3)。該高度（Η)爲ΙΟμηι以上可以充分 隔件之功能可充分確保空氣層（42 )的空隙，丨 5 0 0 μπι以下可以使該突起部（3 2 )之成性變得容易 作爲前述聚光性板（4 1 )，並沒有特別限定， 以舉出微細之棱鏡透鏡，微細之凸透鏡、光柵片等 聚光性透鏡跨單面之全面而被形成之板（sheet )等 散同時透過前述光擴散性基板（3 1 )的透過光以此 板（41 )聚光於光擴散板（3 )之法線方向（Q )。 性板（4 1 )把被形成聚光性透鏡之側的相反側之面 成聚光性透鏡之面）作爲重疊面而與前述光擴散性 3 1 )層積一體化（參照圖2 )。 作爲前述聚光性板（4 1 )之材料，雖無特別限 例如可舉出聚碳酸酯樹脂、ABS樹脂（丙烯腈-苯Z 二烯共聚物樹脂）、甲基丙烯酸樹脂、M S樹脂（ 這樣的 如亦可 右非線 剖面形 等邊三 定，例 削法、 去等。 5 0 0 μχη 獲得間 司時藉 〇 例如可 微細之 。使擴 聚光性 此聚光 (未形 基板（ 定，但 L烯-丁 甲基丙 -18- 201040586 烯酸甲酯（MMA)-苯乙烯共聚物 、A S樹脂（丙烯腈-苯乙烯共聚物 聚乙烯、聚丙烯等）等等。前述聚 ’並未特別限定，例如可以舉出 BEF」（商品名）（厚度125μιη 3 Ομιη之丙烯酸系樹脂層，於此丙 深度（D)爲25μηι而溝底部之張圍 以50μιη之間距間隔（ρ)形成者， 膜公司製造之「Estina (音譯）」 於前述聚光性板（4 1 )例如亦 熱安定劑、防氧化劑、耐天候劑、 、加工安定劑等各種添加劑。 前述聚光性板（41 )之厚度（ 觀點來看’以1 Ομιη以上爲佳。此 )的厚度（C)以不產生撓曲的觀 Q 接劑層（40)接觸於光擴散性基板 的凹部（33)的觀點來看，以 圖2 )。由削減成本，與削減所得 觀點來看，前述聚光性板（41 ) 5 Ο Ο μπι 以下。 作爲前述黏接劑層（40 )之素 如可以舉出丙烯酸系黏接劑、氨基 酯系黏接劑、聚矽氧系黏接劑等。 明之黏接劑，對於可以形成更高品 樹脂）、聚苯乙烯樹脂 f樹脂）、聚烯烴樹脂（ 光性板（4 1 )之市售品 主友 3M公司製造之「 之聚酯膜上被形成厚度 烯酸系樹脂層之表面， 響角度爲90度之V型溝 參照圖2)，與積水薄 (商品名）等。 可含有紫外線吸收劑、 光安定劑、螢光增白劑 C )由確保貼合強度的 外，前述聚光性板（41 點來看，亦即由不使黏 (3 1 )的凹凸形狀面（ 30μιη以上特佳（參照 到的光擴散板的厚度的 的厚度（C )最好在 材，並無特別限定，例 甲酸乙酯系黏接劑、聚 這些之中，使用無色透 質的顯示影像這一點來 -19- 201040586 說，是較佳的。作爲前述黏接劑層（40)，通常使用感壓 型黏接劑。又，此黏接劑之折射率沒有特別限定。 前述黏接劑層（40 )的厚度（Μ )最好爲ΙΟμπι〜 30μιη(參照圖2)。該厚度（Μ)爲ΙΟμιη以上可以確保 充分的黏接強度，同時在30μηι以下可以防止此黏接劑層 (40 )接觸於光擴散性基板（3 1 )的凹部（3 3 )，可以充 分確保空氣層（42 )之空隙量。其中，前述黏接劑層（40 )之厚度（Μ)以被設定於5μιη〜25μηι之範圍特佳。 此外，前述空氣層（42)的厚度（Ε)通常爲Ιμιη〜 400μηι >較佳的厚度（Ε)爲50μιη〜350μιη(參照圖2)。 本發明之光擴散板（3 )，例如以下述方法製造。藉 由在前述聚光性板（4 1 )之聚光性透鏡非形成面上貼合雙 面黏接膜而於前述聚光性板（41)之單面層積黏接劑層（ 40 )，得到具黏接劑之聚光性板。藉由在前述聚光性板（ 4 1 )之聚光性透鏡非形成面上塗布黏接劑而於前述聚光性 板（41)之單面層積黏接劑層（4〇)亦可。另一方面，製 作在單面被形成複數個突起部（3 2 )同時具有在相鄰的突 起部（32 )之間設有凹部（33 )之凹凸形狀面（34 )的光 擴散性基板（3 1 )(參照圖3 )。此光擴散性基板（3 1 ) 之凹凸形狀面（34 )上以前述黏接劑層（40 )接觸的方式 重疊光擴散性基板（3 1 )與具黏接劑之聚光性板（4 1 )而 進行夾壓（搾壓）。藉此使光擴散性基板（3 1 )之突起部 (3 2 )與聚光性板（4 1 )之聚光性透鏡非形成面中介著黏 接劑層（40 )而被接合，得到本發明之光擴散板（3 )。 -20- 201040586 又，即述製1Ξ方法，僅係顯示其—例而已，本發明之 光擴散板（3)並不限於以這樣的製造方法來製造的。 又，本發明之光擴散板（3 )的厚度（s )沒有特別限 定，但以1mm〜5mm爲佳（參照圖2)。此外，本發明之 光擴散板（3 )的大小（面積）沒有特別限定，例如係因 應於目的的面光源裝置（1)或液晶顯示裝置（3〇)的大 小而適當設定者’通常被設計爲20cmx30cm〜 150cm><200cm 之大小 ° 於本發明之面光源裝置（1)及液晶顯示裝置（30) ，作爲前述光源（2 )，未有特別限定，例如除了螢光燈 管、鹵素燈、鎢絲燈等線狀光源以外，還可以使用發光二 極體（LED )等點狀光源。 相關於本發明之光擴散板（3 )、面光源裝置（1 )及 液晶顯示裝置（3 0 )，對前述實施型態並沒有特別的限定 ’只要是在申請專利範圍內，只要沒有逸脫其精神的無論 進行何種設計變更均包含在本發明的範疇。 實施例 其次，針對本發明之具體實施例進行說明，但這些實 施例並非用來限定本發明之用。 <原材料> (光擴散性基板之材料） 透明樹脂A ··苯乙烯樹脂（東洋苯乙烯公司製造之「 -21 - 201040586 HRM40」，折射率1.59) 透明樹脂B : MS樹脂（新日鐵化學公司製造「 MS200NT」，折射率1.57，苯乙烯/甲基丙烯酸甲酯=80 質量份/20質量份） 光擴散劑A : PMMA架橋粒子（住友化學公司製造「 SUMIPEX (音譯）XC1A」，折射率1.49，體積平均粒徑 3 5 μπι 光擴散劑Β:架橋矽氧烷系聚合物粒子（Toray Dow Corning 公司製造「TREFIL DY33-719」，折射率 1.42， 體積平均粒徑2μιη)。 (光擴散劑母料（master batch) Α之調製） 將5 2 · 0質量份透明樹脂A、4 0.0質量份光擴散劑A， 4·〇質量份光擴散劑 B，2.0質量份紫外線吸收劑之 SUMISOAP (音譯）200 (住友化學（股）製造），2.0質 量份熱安定劑之SUMILIZER (音譯）GP (住友化學（股 )製造）乾攪拌後，將此攪拌物投入65mm之二軸壓出機 之漏斗，在汽缸內融溶混合後，壓出爲股（strand )狀而 裁斷得到錠狀之光擴散劑母料A。又，汽缸內的溫度’係 設定爲由漏斗的下部（ 200 °C)起往壓出模附近（ 250 °C) 方向越往下游溫度徐徐變高的方式進行壓出。 (光擴散劑母料（master batch) B之調製） 將78.8質量份透明樹脂B、20.0質量份光擴散劑A ’ -22- 201040586 1.0質量份紫外線吸收劑之LA-31 (旭電化工業 造）’〇.2質量份熱安定劑之SUMILIZER (音譯 友化學（股）製造）乾攪拌後，將此攪拌物投入 二軸壓出機之漏斗，在汽缸內融溶混合後，壓 strand )狀而裁斷得到錠狀之光擴散劑母料b。 內的溫度’係設定爲由漏斗的下部（200°C )起 附近（25 0 °C )方向越往下游溫度徐徐變高的方 (聚光性板A ) 使用於單面上深度（D)爲11·5μιη、溝底部 度爲9 0度之V形溝以間距間隔（ρ )爲23.0 μιη 透明PET (聚對苯二甲酸乙二酯）樹脂製之厚 6 0 μηι之薄膜。 <實施例1 > 乾攪拌97.0質量份透明樹脂a、5.0質量份 母料 A之後，以汽缸內溫度190〜250 °(：之第一 溶混練而供給至給料塊（feed block)。另一方 缸內溫度190〜250 °C之第二壓出機融溶混練光擴 B而供給至給料塊（feed block)。 由前述第一壓出機對給料塊供給的樹脂成爲 基層），由前述第二壓出機對給料塊供給的樹脂 (兩面）的方式在押出樹脂溫度250 °C由多， (股）製 )GP (住 6 5 m m 之 出爲股（ 又，汽缸 往壓出模 式進行壓 之張開角 所形成的 度（C ) 光擴散劑 壓出機融 面，以汽 散劑母料 中間層（ 成爲表層 K管模（ -23- 201040586 multi-manifold-die)進行共壓出成形，以拋光輥進行夾壓 與冷卻，藉以製作厚度2.0mm之3層層積板（中間層 1.9mm，表層0_05mmx2 )所構成的光擴散性基板（3 1 )。 接著，於所得到的光擴散性基板（3 1 )之單面的全面 ，使用熱壓機（神藤金屬工業所製造，神藤式ASF型油壓 壓機）將柱狀透鏡形狀之突起部（剖面形狀爲約略半圓柱 形狀之突起部）（3 2 )以圖4所示之配置態樣使突設形成 多數個而得厚度（N)爲2.0mm之光擴散性基板（31 )( 參照圖3、4)。又，於前述熱壓機上方側之金屬模之下面 (壓面）穿設多數個對應於前述突起部的短凹溝。此外， 在根據前述熱壓機之熱衝壓，係將熱壓機之上面側溫度設 爲1 60°C，下面側溫度設定爲70°C的狀態下進行約3分鐘 加壓。 如此所得到的光擴散性基板（3 1 )的凹凸形狀面（3 4 )，係被設計爲突起部（32)之高度（H)爲150μιη、突 起部（32)之長邊長度（Τ)爲8 00 μηι、長邊方向鄰接的 突起部彼此之重心間距離（U)爲1200 μπι、突起部（32) 之短邊長度（L )爲3 8 9μηι、短邊方向上相鄰突起部彼此 之重心間距離（F )爲1 65 0μιη、偏移距離（Κ )爲600μηι 的構成（參照圖4 )。 另一方面，聚光性板A ( 4 1 )之聚光性透鏡非形成面 (平滑面）上貼合雙面黏接膜而於聚光性板A(41)之單 面層積厚度（Μ )爲20μηι之黏接劑層（40 ) ’得到具黏 接劑之聚光性板。 -24- 201040586 於前述光擴散性基板（3 1 )之凹凸形狀面（34 )上以 前述黏接劑層（4〇)接觸的方式重疊光擴散性基板（31) 與具黏接劑之聚光性板（4 1 )後’藉由將此挾壓而製作呈 圖2所示的剖面形狀之光擴散板（3 )。 在此具聚光層光擴散板（3)，如圖2所示，可以在 黏接劑層（40 )與光擴散性基板（3 1 )之凹部（平坦部） (33)之間形成厚度（E)爲130μιη的空氣層（42)。 <比較例1 > 除了未對藉由共壓出成形得到的光擴散性基板使用熱 壓機進行突起部（3 2 )的形成以外，與實施例1同樣的進 行而製作光擴散板。在此光擴散板，光擴散性基板與聚光 性板Α藉由黏接劑層被全面黏接，光擴散性基板與聚光性 板A之間不存在空氣層。又，藉由共壓出成形所得到的光 擴散性基板之表面（重疊面）之算術平均粗糙度Ra爲 4.78μιη，表面凹凸之十點平均粗糙度Rz爲28.61μιη，表 面凹凸之平均間隔Rsm爲148μιη。 <比較例2 > 除了使用藉由改變熱壓機之上方側之金屬模的下面（ 壓面）之凹溝形狀而得到的，沿著基板的長邊方向由一端 側往另一端側連續延伸的（長度7〇mm的）柱狀透鏡形狀 之突條部（突起部）（參照圖5)有多數條突設形成爲平 行狀的光擴散性基板（3 1 )以外，與實施例1同樣進行而 -25- 201040586 製作光擴散板。 又，突條部之高度（H)爲15 0μηι、突條部之短邊長 度（L )爲300μιη、短邊方向相鄰的突條部彼此之重心間 距離（F)爲 2250μηι。 <比較例3 > 除了使用藉由改變熱壓機之上方側之金屬模的下面（ 壓面）之凹溝形狀而得到的’沿著基板的長邊方向由一端 側往另一端側連續延伸的（長度7〇mm的）柱狀透鏡形狀 之突條部（突起部）（參照圖5 )有多數條突設形成爲平 行狀的光擴散性基板（3 1 )以外，與實施例！同樣進行而 製作具聚光層之光擴散板。 又’突條部之高度（H)爲150 μηι'突條部之短邊長 度（L )爲3 0 0 μηι、短邊方向相鄰的突條部彼此之重心間 距離（F )爲 3 25 0μπι。 針對如前所述進行而製作的各光擴散板依照下列評估 法進行評估。這些結果顯示於表1。 -26- 201040586 ο Ο I撇 平均亮度 1 (cd/m2) 6680 5769 6563 6643 亮度均勻度 (%) 99.2 98.7 99.3 99.3 鄯驩 蘅·Ν 德3 壊 1 摧 突起部之構成 偏移距離κ (μΐΏ) 600 1 1 1 F/L 8.97 1 in 10.8 重心間距離F (μηι) 3490 1 2250 3250 短邊之長度L (μπι) 389 1 300 300 U/T τ-Η 1 1 1 :重心間距離U (μ m ) 1200 1 1 1 長邊之長度τ (μιη) 800 1 (連續） (連續） 實施例1 比較例1 比較例2 比較例3 -27- 201040586 <平均亮度及亮度均勻度評估法> 由市售之20吋型液晶電視取出液晶面板、各種光學 膜及光擴散板之後，在抵接於燈箱（內部相互隔開配置複 數根螢光燈管）之框緣部的前面的狀態下，配置固定在前 述所製作的光擴散板（實施例物品、比較例物品）塞住燈 箱之開放面。在設置此光擴散板的狀態使用亮度測定計（ (股）Eye System公司製造之「Eye Scale-3WS」測定其 亮度。亮度最小値爲「C 1」亮度最大値爲「C2」時， 亮度均勻度（％) = (C1/C2) xlOO 以前式所求得之値作爲亮度均勻度（％ )。 又，前述亮度測定係如下述進行的。在恆溫恆濕（溫 度2 5.0 °C、濕度50.0% )之暗室內之地板上使液晶電視以 其前面側爲上面（背面與地面抵接）地配置，液晶電視之 前面之全部都被照進來的方式在液晶電視的上方位置朝向 下方配置照相機。此時，由液晶電視的前面至照相機爲止 的距離爲 65.0cm，亮度測定計之測定條件設定爲快門 :1 /500、利得：5、光圈：16，以液晶電視的前面之中央部 爲中心之60mmx60mm之範圍指定爲測定點而分別測定在 各測定點（2601處）之亮度，將這些亮度的平均値作爲平 均亮度（cd/in2 )，同時將此測定値之中由亮度最小値與 亮度最大値求出亮度均勻度（％)。 由表1可知，使用本發明之實施例1之光擴散板構成 的面光源裝置，於正面方向（法線方向）可得高亮度同時 亮度均句性亦優異。此外，在實施例1之光擴散板，因光 -28- 201040586 - 擴散性基板與聚光性板係中介著黏接劑層而被接合，所以 光擴散性基板與聚光性板不會滑擦，不會在光擴散板產生 擦傷。 相對於此，使用比較例1之光擴散板而構成的面光源 裝置，藉由黏接劑之全面黏接使得光擴散性基板與聚光性 板之間不存在空氣層’所以於正面方向（法線方向）亮度 非常低。 π 此外，在使用比較例2或比較例3之光擴散板而構成 〇 的面光源裝置，於正面方向（法線方向）無法獲得亮度。 【產業上利用可能性】 . 本發明之光擴散板，適於作爲面光源裝置用之光擴散 板來使用，但不限於這樣的用途。此外，本發明之面光源 裝置，適於作爲液晶顯示裝置用之背光來使用，但不限於 這樣的用途。 ❹ 【圖式簡單說明】 圖1係顯示相關於本發明之液晶顯示裝置之一實施型 態之模式圖。 圖2係顯示相關於本發明之光擴散板之一實施型態之 剖面圖。 圖3係顯示光擴散性基板之剖面圖。 • 圖4係顯示光擴散性基板之突起部的配置態樣之一例 之平面圖。 -29- 201040586 圖5係顯示比較例2、3之光擴散性基板之突條部（ 突起部）之配置態樣之平面圖。 【主要元件符號說明】 1 =面光源裝置 2 :光源 3 :光擴散板 2 0 :液晶面板 3 0 :液晶顯示裝置 3 1 :光擴散性基板 3 2 :突起部 3 3 :凹部 3 4 :凹凸形狀面 35 :長邊 36 :短邊 4 〇 :黏接劑層 41 :聚光性板 42 :空氣層 G :突起部的重心 T:突起部的底面之長邊的長度 L:突起部的底面之短邊的長度 U :於長邊方向相鄰的突起部彼此之重心間距離 F :於短邊方向相鄰的突起部彼此之重心間距離 K :偏離距離（長邊方向） -30-The configuration of the second relation of 8.0$F/L is preferable (refer to Fig. 4). When the configuration β is used, the void of the air layer (42) formed between the adhesive layer (40) and the concave portion (33) of the uneven surface (34) of the light diffusing substrate 0 (31) can be formed. Expanding in the short side direction allows light to be transmitted at a higher transmittance, so that the brightness in the front direction can be further increased. In other words, by setting F to 4 〇〇μηι or more, the air layer (42) can be sufficiently formed in the concave portion of the concave-convex surface (34) of the adhesive layer (40) and the light-diffusing substrate (31) ( Between 33), by making F be 5.0 mm or less, it is possible to prevent the condensing plate (4 1 ) from being deflected and the condensing plate (4 1 ) Ο contacting or approaching the light diffusing substrate (3 1 ) a concave portion (3 3 ) of the concave-convex shape surface (34). In addition, by establishing the relationship of 8·0 SF/L, the gap of the air layer (42) can be expanded in the short-side direction, and light can be transmitted at a higher transmittance, so that the brightness in the front direction can be further increased. . In the present invention, the light-diffusing substrate (3 1 ) can be used as long as it can diffuse transmitted light. A plate in which light-diffusing particles (light-diffusing agents) are dispersed in a transparent material is suitably used. The light-diffusing substrate (3 1 ) is not particularly limited. For example, a single-layer plate made of a transparent resin or a base layer made of a transparent resin -15-201040586 may be laminated on at least one surface. A laminated plate made of a transparent resin or a laminated plate of a plurality of other layers. The transparent material constituting the light-diffusing substrate (31) is not particularly limited, and examples thereof include a transparent resin and inorganic glass. As the transparent resin of the above, it is preferable to use a transparent thermoplastic resin from the viewpoint of easy molding. The transparent thermoplastic resin is not particularly limited, and examples thereof include polycarbonate resin, ABS resin (acrylonitrile-styrene-butadiene copolymer resin), and methacrylic resin 'MS resin (methicone). Methyl ester (MMA)-styrene copolymer resin), polystyrene resin, AS resin (acrylonitrile-phenylethyl copolymer resin), polyethylene terephthalate, olefin resin (polyethylene, polypropylene) , cyclic polyolefin, cyclic anahydrocarbon copolymer, etc.) and the like. The light-diffusing particles are not particularly limited as long as they are incompatible with the transparent material constituting the light-diffusing substrate (3 i ) and the particles having different refractive indices from the transparent resin can diffuse and transmit light. Anything can be used. use. For example, inorganic particles such as cerium oxide particles, calcium carbonate particles, barium sulfate particles, titanium oxide particles, aluminum hydroxide particles, inorganic glass particles, mica particles, talc particles, white carbon ink particles, magnesium oxide particles, and zinc oxide particles may also be used. As the particles, organic particles such as methacrylic bridging resin particles, methacrylic high molecular weight resin particles, styrene bridging resin particles, high molecular weight resin particles, and sand oxide polymer particles may be used. As the light-diffusing particles, one type of the above-described exemplified one may be used, or two or more of them may be used in combination. As the light-diffusing particles, those having a volume average particle diameter of from -16 to 201040586 0.1 μηι to 50 μηι are usually used. Further, the volume average particle diameter (d5q) is a particle diameter and a volume of the whole particles, and the volume is calculated by sequentially starting from a small particle diameter, and the volume of the integrated volume to the total volume of the entire particles is 50%. The amount of the light-diffusing particles to be used varies depending on the degree of diffusion of the light to be transmitted by the target. Generally, the content of the light-diffusing particles in an amount of 1 part by mass of the transparent material is 0.01 parts by mass to 20 parts by mass. The content of the light-diffusing particles in 100 parts by mass of the transparent material is preferably from 10,000 parts by mass to 10 parts by mass. From the viewpoint of light diffusibility, the absolute 値 of the difference between the refractive index of the transparent material and the refractive index of the light-diffusing particles is preferably 〇. 2 or more, and the absolute enthalpy is from the viewpoint of light transmittance. It is preferably 〇. 1 3 or less. That is, the absolute 値 of the difference between the refractive index of the transparent material and the refractive index of the light-diffusing particles is preferably in the range of 0·〇2 to 0.13. The light-diffusing substrate (31) may contain, for example, various additives such as an ultraviolet absorber, a heat stabilizer, an antioxidant, a weather resistant agent, a photosetter, a fluorescent whitening agent, and a processing stabilizer. The thickness (Ν) of the light-diffusing substrate (31) is usually 0.1 mm to 10 mm. The cross-sectional shape of the protrusion (32) is not particularly limited. For example, in addition to the approximately semicircular shape, an approximately semi-elliptical shape, a flat curved line shape, an approximately rectangular shape, an approximately triangular shape, or the like may be mentioned. Further, in the above embodiment, the cross-sectional shape of the protruding portion (32) is a semicircular shape, and a cross-sectional shape which is symmetrical with respect to the left and right lines is formed for a normal line passing through the center of the circle (line -17-201040586 perpendicular to the horizontal plane). However, it is not limited to the configuration of the cross section which can be formed as a left-right non-linear symmetry. For example, the arc on the left side is more swelled to the left side of the front side than the arc on the right side. Further, when the shape of the projections (3 2 ) is a triangular shape, the shape may be a bilateral shape that is symmetrical with respect to the left and right lines, or a triangular shape that is non-linearly symmetrical with respect to the left and right. The formation method of the protrusions (3 2 ) is not particularly limited to, for example, a thermal transfer method according to a mold, an injection molding method, a die-cutting extrusion molding method, and a melt-forming press-forming method according to the engraving roll. The height (H) of the protrusion (32) is preferably ΙΟμηι~ (see Fig. 3). When the height (Η) is ΙΟμηι or more, the function of the spacer can be sufficiently ensured, and the void of the air layer (42) can be sufficiently ensured, and the formation of the protrusion (3 2 ) can be easily made as the condensed light as 丨500 μm or less. The slab (4 1 ) is not particularly limited, and a fine prism lens is used. A condensing lens such as a fine convex lens or a lenticular sheet is spread across the entire surface of a single sheet and transmitted through the light. The transmitted light of the diffusing substrate (31) is condensed by the plate (41) in the normal direction (Q) of the light diffusing plate (3). The plate (4 1 ) is formed by laminating the surface of the condensing lens with the surface on the side opposite to the side on which the condensing lens is formed as a condensing lens as a superimposed surface (see Fig. 2 ). The material of the condensing plate (4 1 ) is not particularly limited, and examples thereof include a polycarbonate resin, an ABS resin (acrylonitrile-benzene Z diene copolymer resin), a methacryl resin, and an MS resin. If you can also use the right non-line profile to define the equal sides, such as the cutting method, go to etc. 5 0 0 μχη When obtaining the inter-division, for example, it can be finely condensed, so that the diffused light is concentrated (unshaped substrate , but L-butyl methyl propyl-18- 201040586 methyl methacrylate (MMA)-styrene copolymer, AS resin (acrylonitrile-styrene copolymer polyethylene, polypropylene, etc.), etc. For example, a BEF" (trade name) (acrylic resin layer having a thickness of 125 μm 3 Ομηη) may be mentioned, and the C depth (D) is 25 μm and the bottom of the groove is formed at intervals of 50 μm (ρ). "Estina" manufactured by the company is a kind of various additives such as a heat stabilizer, an antioxidant, an anti-weathering agent, a processing stabilizer, etc., in the above-mentioned concentrating plate (4 1 ). The thickness of the concentrating plate (41) (point of view 'with 1 Ομιη The thickness (C) of this is preferably such that the Q-attachment layer (40) which does not cause the deflection contacts the concave portion (33) of the light-diffusing substrate, as shown in Fig. 2). The condensing plate (41) 5 Ο Ο μπι or less is used as the above-mentioned adhesive layer (40), and examples thereof include an acrylic adhesive, an amino ester adhesive, and a polycondensation. Oxygen-based adhesives, etc.. The adhesives of Ming, for the production of higher-quality resins), polystyrene resin (resin), and polyolefin resins (manufactured by 3M, a commercial product of optical board (4 1 )) "The surface of the polyester film is formed with a thickness of the olefinic resin layer, the V-shaped groove having a 90-degree angle is shown in Fig. 2), and the water is thin (trade name). It may contain an ultraviolet absorber or a light stabilizer. The fluorescent whitening agent C) is provided by the condensing sheet (the point of the point of view of 41 points, that is, the uneven shape of the adhesive (3 1 ) (30 μm or more is excellent) (refer to The thickness (C) of the thickness of the light diffusing plate is preferably in the material, and is not particularly limited. For example, ethyl formate bonding Among these, it is preferable to use a colorless and permeable display image as -19-201040586. As the above-mentioned adhesive layer (40), a pressure-sensitive adhesive is usually used. The thickness of the adhesive layer (40) is preferably ΙΟμπι to 30 μm (see Fig. 2). The thickness (Μ) is ΙΟμηη or more to ensure sufficient bonding strength. At the same time, the adhesive layer (40) can be prevented from contacting the concave portion (3 3 ) of the light-diffusing substrate (31) at 30 μm or less, and the amount of voids in the air layer (42) can be sufficiently ensured. The thickness (Μ) of the adhesive layer (40) is particularly preferably set in the range of 5 μm to 25 μm. Further, the thickness (Ε) of the air layer (42) is usually Ιμηη to 400μηι > and the preferred thickness (Ε) is 50 μm to 350 μm (refer to Fig. 2). The light diffusing plate (3) of the present invention is produced, for example, by the following method. The adhesive layer (40) is laminated on one side of the concentrating plate (41) by bonding a double-sided adhesive film on the non-formed surface of the condensing lens of the concentrating plate (4 1 ) , to obtain a concentrating plate with an adhesive. The adhesive layer (4〇) may be laminated on one side of the concentrating plate (41) by applying an adhesive on the non-formed surface of the condensing lens of the concentrating plate (41). . On the other hand, a light-diffusing substrate having a plurality of protrusions (3 2 ) formed on one surface and having a concave-convex surface (34) of a concave portion (33) between adjacent protrusions (32) is formed ( 3 1 ) (refer to Figure 3). The light-diffusing substrate (3 1 ) and the light-concentrating plate with an adhesive agent are stacked on the uneven surface (34 ) of the light-diffusing substrate ( 3 1 ) so as to be in contact with the adhesive layer ( 40 ). 1) and crimping (pressing). Thereby, the protrusion (3 2 ) of the light-diffusing substrate (31) and the condensing lens non-formation surface of the condensing plate (4 1 ) are bonded to each other via the adhesive layer (40), thereby obtaining the present. Invented light diffusing plate (3). -20- 201040586 In addition, the method of the present invention is merely shown, and the light diffusing plate (3) of the present invention is not limited to being manufactured by such a manufacturing method. Further, the thickness (s) of the light-diffusing sheet (3) of the present invention is not particularly limited, but is preferably 1 mm to 5 mm (see Fig. 2). Further, the size (area) of the light-diffusing sheet (3) of the present invention is not particularly limited, and is appropriately set, for example, depending on the size of the surface light source device (1) or the liquid crystal display device (3). The surface light source device (1) and the liquid crystal display device (30) of the present invention are not particularly limited as long as the light source device (1) and the liquid crystal display device (30) of the present invention, for example, except for a fluorescent tube or a halogen lamp. In addition to a linear light source such as a tungsten lamp, a point light source such as a light-emitting diode (LED) can also be used. The light diffusing plate (3), the surface light source device (1), and the liquid crystal display device (30) according to the present invention are not particularly limited in the foregoing embodiments, as long as they are within the scope of the patent application, as long as there is no escape. Any design changes made by the spirit of the spirit are included in the scope of the present invention. EXAMPLES Next, specific examples of the invention are described, but these examples are not intended to limit the invention. <Materials> (Material of Light-Diffusing Substrate) Transparent Resin A ·· Styrene Resin ("21 - 201040586 HRM40" manufactured by Toyo Styrene Co., Ltd., refractive index: 1.59) Transparent Resin B: MS Resin (Nippon Steel) Chemical company manufactures "MS200NT" with a refractive index of 1.57, styrene/methyl methacrylate = 80 parts by mass / 20 parts by mass. Light diffusing agent A: PMMA bridging particles ("Sumitotid Chemical Co., Ltd." "SUMIPEX (transliteration) XC1A", refraction Rate 1.49, volume average particle diameter 3 5 μπι Light diffusing agent Β: bridged siloxane polymer particles ("TREFIL DY33-719" manufactured by Toray Dow Corning Co., Ltd., refractive index 1.42, volume average particle diameter 2 μιη). (Light diffusion) Master batch 调制 modulate) 5 2 · 0 parts by mass of transparent resin A, 4 0.0 parts by mass of light diffusing agent A, 4 · 〇 by mass of light diffusing agent B, 2.0 parts by mass of UV absorber SUMISOAP ( Transliteration) 200 (manufactured by Sumitomo Chemical Co., Ltd.), 2.0 mass parts of SUMILIZER (transliteration) GP (manufactured by Sumitomo Chemical Co., Ltd.), after dry stirring, the stirrer is put into a funnel of 65 mm two-axis extruder In the steam After melt-mixing, it is extruded into a strand shape and cut into a strand-shaped light diffusing agent masterbatch A. Further, the temperature in the cylinder is set to be pressed out from the lower part of the funnel (200 °C). The temperature is gradually increased in the vicinity of the mold (250 ° C) in the direction of the downstream. (Preparation of light diffuser master batch B) 78.8 parts by mass of transparent resin B, 20.0 parts by mass of light diffusing agent A ' -22- 201040586 1.0 part by mass of UV-absorbing agent LA-31 (made by Asahi Kasei Industrial Co., Ltd.) 〇. 2 parts by mass of SUMILIZER (manufactured by Toshiyuki Chemical Co., Ltd.) after dry stirring, the mixture is put into the mixture. The funnel of the two-axis extruder is melted and mixed in the cylinder, and then pressed to obtain the ingot-shaped light diffusing agent masterbatch b. The temperature inside is set to a point where the temperature gradually rises from the lower part (200 ° C) in the vicinity of the funnel (200 ° C) to the downstream (concentrating plate A) is used on one surface depth (D) A film having a thickness of 60 μm made of transparent PET (polyethylene terephthalate) resin having a pitch of (p) of 13.0 μm and a V-shaped groove having a groove bottom degree of 90 degrees. <Example 1> After dry stirring 97.0 parts by mass of the transparent resin a and 5.0 parts by mass of the master batch A, the mixture was supplied to a feed block at a cylinder temperature of 190 to 250 ° (the first solution was kneaded. The second extruder having a temperature of 190 to 250 ° C in one cylinder melts and kneads the light expansion B and supplies it to a feed block. The resin supplied from the first extruder to the feed block becomes a base layer, The second extruder presses the resin (two sides) of the feed block in a manner that the resin temperature is 250 °C, and the GP is made up of 6 5 mm (again, the cylinder is pressed into the extrusion mode). Degree of formation of the opening angle of the pressure (C) The light diffusing agent is pressed out of the melted surface of the machine, and is formed by the intermediate layer of the vapour masterbatch (becoming the surface K-tube mold (-23-201040586 multi-manifold-die), The polishing roll was subjected to nip and cooling to prepare a light-diffusing substrate (3 1 ) composed of a three-layer laminated plate (intermediate layer 1.9 mm, surface layer 0_05 mm×2) having a thickness of 2.0 mm. Next, the obtained light diffusing substrate was used. (3 1) One-sided comprehensive, using hot press (Shenjin Metal Industry The manufactured "Shen-ASF-type hydraulic press" has a projection of a lenticular lens shape (a projection having a cross-sectional shape of a substantially semi-cylindrical shape) (3 2 ) in a configuration as shown in FIG. A light diffusing substrate (31) having a thickness (N) of 2.0 mm (see FIGS. 3 and 4) is obtained. Further, a plurality of the lower surface (pressing surface) of the metal mold on the upper side of the hot press are corresponding to In the hot stamping according to the above-described hot press, the temperature of the upper side of the hot press is set to 1 60 ° C, and the temperature of the lower side is set to 70 ° C. The uneven surface (3 4 ) of the light-diffusing substrate (3 1 ) thus obtained is designed such that the height (H) of the protrusion (32) is 150 μm and the long side of the protrusion (32) The length (Τ) is 8 00 μηι, the distance between the centers of the protrusions adjacent to each other in the longitudinal direction (U) is 1200 μπι, and the length of the short side (L) of the protrusion (32) is 3 8 9 μηι, and the phase in the short side direction The distance between the center of gravity of the adjacent protrusions (F) is 1 65 0 μιη, and the offset distance (Κ ) is 600 μηι (refer to the figure). 4) On the other hand, on the non-forming surface (smooth surface) of the condensing lens of the concentrating sheet A (4 1 ), a double-sided adhesive film is bonded to the single-layer layer of the condensing sheet A (41). The adhesive layer (40) having a thickness (Μ) of 20 μm is obtained by obtaining a light-concentrating plate having an adhesive. -24- 201040586 On the uneven surface (34) of the light-diffusing substrate (3 1 ) After the adhesive layer (4〇) is in contact with each other, the light diffusing substrate (31) and the light-concentrating plate (4 1 ) having the adhesive are superposed, and the stamping layer is formed by pressing the stamping layer as shown in FIG. A light diffusing plate (3) of a cross-sectional shape. Here, the concentrating layer light diffusing plate (3), as shown in Fig. 2, can form a thickness between the adhesive layer (40) and the concave portion (flat portion) (33) of the light diffusing substrate (31). (E) is a 130 μm air layer (42). <Comparative Example 1> A light diffusing plate was produced in the same manner as in Example 1 except that the projections (3 2 ) were not formed using a heat press on the light-diffusing substrate obtained by the co-extrusion molding. In the light diffusing plate, the light diffusing substrate and the concentrating sheet are integrally bonded by the adhesive layer, and there is no air layer between the light diffusing substrate and the condensing sheet A. Further, the arithmetic mean roughness Ra of the surface (overlapping surface) of the light-diffusing substrate obtained by the co-extrusion molding was 4.78 μm, the ten-point average roughness Rz of the surface unevenness was 28.61 μm, and the average interval Rsm of the surface unevenness It is 148μηη. <Comparative Example 2 > Except that the shape of the groove of the lower surface (pressure surface) of the metal mold on the upper side of the hot press is changed, the longitudinal direction of the substrate is continuous from one end side to the other end side. The protruding portion (protrusion portion) (see FIG. 5) of the lenticular lens shape (see FIG. 5 having a length of 7 mm) has a plurality of light-diffusing substrates (3 1 ) protruding in a parallel shape, and the first embodiment The same was done while -25- 201040586 made a light diffuser. Further, the height (H) of the ridge portion is 150 μm, the short side length (L) of the ridge portion is 300 μm, and the distance between the centers of gravity of the ridge portions adjacent in the short side direction (F) is 2250 μm. <Comparative Example 3 > In addition to the use of the groove shape of the lower surface (pressure surface) of the mold on the upper side of the hot press, the 'long side direction of the substrate is continuous from the one end side to the other end side The protruding portion (protrusion portion) (see FIG. 5 ) of the lenticular lens shape (see FIG. 5 ) which is extended (having a length of 7 mm) has a plurality of light-diffusing substrates ( 3 1 ) which are formed in a parallel shape, and the embodiment! A light diffusing plate having a concentrating layer was produced in the same manner. Further, the height (H) of the ridge portion is 150 μηι', and the short side length (L) of the ridge portion is 300 μm, and the distance between the centers of the ridges adjacent to each other in the short side direction (F) is 3 25 0μπι. Each of the light diffusing plates produced as described above was evaluated in accordance with the following evaluation methods. These results are shown in Table 1. -26- 201040586 ο Ο I撇 average brightness 1 (cd/m2) 6680 5769 6563 6643 Brightness uniformity (%) 99.2 98.7 99.3 99.3 鄯欢蘅·Ν 德3 壊1 Destruction of the protrusions offset distance κ (μΐΏ) 600 1 1 1 F/L 8.97 1 in 10.8 Distance between centers of gravity F (μηι) 3490 1 2250 3250 Length of short side L (μπι) 389 1 300 300 U/T τ-Η 1 1 1 : distance between centers of gravity U (μ m 1200 1 1 1 Length of the long side τ (μιη) 800 1 (continuous) (continuous) Example 1 Comparative Example 1 Comparative Example 2 Comparative Example 3 -27- 201040586 <Average brightness and brightness uniformity evaluation method> After the liquid crystal panel, the various optical films, and the light diffusing plate are taken out, the commercially available 20-inch LCD TV is placed in front of the frame edge portion of the light box (the plurality of fluorescent tubes are arranged inside each other). The light diffusing plate (the article of the example and the article of comparative example) produced as described above was fixed to the open surface of the light box. In the state in which the light diffusing plate is provided, the brightness is measured using a brightness meter (Eye Scale-3WS, manufactured by Eye System, Inc.). When the minimum brightness is "C1", the maximum brightness is "C2", and the brightness is uniform. Degree (%) = (C1/C2) xlOO The enthalpy obtained by the previous equation is used as the brightness uniformity (%). The brightness measurement is performed as follows. Constant temperature and humidity (temperature 2 5.0 °C, humidity 50.0) In the floor of the dark room, the liquid crystal television is placed with the front side as the upper side (the back side is in contact with the ground), and the front side of the liquid crystal television is illuminated so that the camera is placed downward at the upper position of the liquid crystal television. At this time, the distance from the front of the liquid crystal television to the camera is 65.0 cm, and the measurement conditions of the luminance meter are set to shutter: 1 / 500, gain: 5, aperture: 16, centering on the center of the front of the liquid crystal television. The range of 60 mm x 60 mm is specified as the measurement point, and the brightness at each measurement point (2601) is measured, and the average 値 of these brightnesses is taken as the average brightness (cd/in2), and the brightness is minimized among the measurement 値亮度 and brightness are the largest, and the brightness uniformity (%) is obtained. As is apparent from Table 1, the surface light source device using the light diffusing plate of the first embodiment of the present invention can obtain high brightness and brightness in the front direction (normal direction). In addition, in the light diffusing plate of the first embodiment, the light diffusing substrate and the light diffusing substrate are bonded to each other by the light diffusing substrate and the light collecting plate. The optical plate does not slip and does not cause scratches on the light diffusing plate. In contrast, the surface light source device constructed using the light diffusing plate of Comparative Example 1 is made to have a light diffusing substrate by integral bonding of the adhesive. There is no air layer between the condensing plate and the illuminating plate. Therefore, the brightness in the front direction (normal direction) is very low. π In addition, the surface light source device using the light diffusing plate of Comparative Example 2 or Comparative Example 3 is used. In the front direction (normal direction), the brightness is not obtained. [Industrial Applicability] The light diffusing plate of the present invention is suitably used as a light diffusing plate for a surface light source device, but is not limited to such use. Invention The surface light source device is suitable for use as a backlight for a liquid crystal display device, but is not limited to such use. ❹ [Simplified description of the drawings] Fig. 1 is a schematic view showing an embodiment of a liquid crystal display device according to the present invention. Fig. 2 is a cross-sectional view showing an embodiment of a light diffusing plate according to the present invention. Fig. 3 is a cross-sectional view showing a light diffusing substrate. Fig. 4 is a view showing a configuration of a protruding portion of a light diffusing substrate. Fig. 5 is a plan view showing an arrangement of ridges (protrusions) of the light diffusing substrate of Comparative Examples 2 and 3. [Main element symbol description] 1 = surface light source device 2 :Light source 3 : Light diffusing plate 20 : Liquid crystal panel 30 : Liquid crystal display device 3 1 : Light diffusing substrate 3 2 : Projection portion 3 3 : Concave portion 3 4 : Concave-convex shape surface 35: Long side 36: Short side 4 〇 : adhesive layer 41 : condensing plate 42 : air layer G : center of gravity T of the protrusion: length L of the long side of the bottom surface of the protrusion: length U of the short side of the bottom surface of the protrusion: in the longitudinal direction The distance between the center of gravity of the adjacent protrusions is F: on the short side Adjacent each other protrusion distance of the center of gravity K: offset distance (the longitudinal direction) -30-