200530697 九、發明說明： 【發明所屬之技術領域】 本發明是有關於一種直下型背光。 【先前技術】 液晶顯示裝置等所使用的背光，大致分為侧光型的背 光和直下型的背光。其中，直下型的背光因為具有適於大 型化、容易得到尚輝度的特徵等，所以特別可作為大型平 面發光裝置而得到廣泛應用。而且，在液晶顯示裝置中， 作為例如15英寸以上的大型晝面所使用的平面發光裝 置，也越來越多地使用直下型的背光。 利用圖示對習知的一般性直下型背光進行說明。這 裏，是以利用液晶面板等顯示部和光學片的場合作為例子 進行說明。圖7為與線狀的光源31的長邊直交之平面的斷 面圖。如圖7所示，該背光由多數條光源（燈）31、作為 具有開口部且在内部具有光源31的罩殼之下框32、在下' 框的内面所設置之反射層33、設置有液晶面板4〇等顯示 部之框狀的上框34、在上框34和下框32之間所夾持的光 學片35及擴散板36構成。光源31使用冷陰極管型的螢光 燈。在上框34以置有用於保持液晶面板等顯示部的樹脂 制引導凸緣37。像該圖7所*的例子那樣，在習知 型背光中，上框34和擴散板36分別作為不同的構件，且 =由擴散板36單獨形成-構件。而且，擴散板 整體範圍内厚度-㈣平板狀構件（例如參照專利文獻;、 及專利文獻2)。 14154pif 5 200530697 〔專利文獻1〕日本專利早期公開之特開平丨〇一 106342 號公報 〔專利文獻2〕日本專利早期公開之特開2002— 182184 號公報 在上述這種習知的直下型背光中，存在擴散板容易產生撓 曲等變形之問題。之所以產生這樣的變形，是因為擴散板 自重以及外部應力的影響、時效變化、來自反射片的熱的 影響等。當擴散板上產生撓曲等變形時，如擴散板產生撓 曲等變形，則透過光的擴散均勻性下降，所以作為背光的 發光品質下降。而且，在使用例如液晶面板這樣的顯示部 和光學片的情況下，沿擴散板的變形，會在這些光學片和 液晶面板上也產生變形，造成液晶顯示不均勻。而且，因 為上框等和擴散板各成一體，所以也存在背光的構件數量 立曰加，因構件的管理成本和背光的組裝工程數增加而造成 之組裝成本增大的問題。 【發明内容】 本發明的目的是提供一種鑒於該狀況而形成的，可抑 制擴散板的變形並提高發光品質，而且構件數量少的直下 型背光。 本發明的直下型背光包括使光源發出的光透過並擴散 的擴散板和在該擴散板的周圍設置的框部所一體成形之擴 散板一體框部、具有配置有前述擴散板的開口部且在内部 配置有光源的下框；其特徵在於：前述擴散板具有從其中 央侧向周邊侧厚度連續增加的厚度變化部。 14154pif 6 200530697 部使擴餘何1部被—體成形，所以可利用框 、咸+ 加強而抑制該擴散板的變形’且使構件數量 用厚度變化部使作用在擴散板上的自重等 心力被刀政，使擴散板變得難以撓曲。 厚度散板也可採用只由前述 韓Ml·邱，&、/、冓成巧樣一來，擴散板整體形成厚度 ^ ° 以形成一種從擴散板的中央部到周邊部，厚产 ϊ:=?構成’使擴散板的撓曲達到最小限度。而且： 光可得到輝度高’所以特別是作為圖像爾 声、車H i别述擴散板也可採用由從其中央侧向周邊側厚 f連j蚊厚度變化部、厚度—定之等厚部形成的構 透過率變得一定’容易使輝度均勾，所以 前诚料 存 情況下，前述厚度變化部設於 中央的周邊部’前述等厚部設於前述厚度變化部的 輝度變得=這樣一來，可利用等厚度使擴散板中央部的 日，Γ勻’且利用厚度變化部抑制擴散板的撓曲。而 用的北t中央部較周邊部輝度增高，所以特別是作為圖像 用的背光可得到高發光品質。 冬 大擴放板的厚度在0 5mm以上且在5mm以下為佳。這是 二士 1 〇‘5mm薄，則剛性不足而容易發生變形，同時 严，S不1而使發光品質低下。而且因為，如較5麗 子、重’定得過大而容易產生撓曲，同時材料的使用量 14154pif 200530697 增多而使製造成本上升。而且，藉由使擴散板的厚度為0·5 m的範圍’可抑制擴散板的厚度差過大而使輝度變ρ 過分不均勻。 f 刚述擴散板的表面平滑地進行連續為佳。這是因為， 如果存在不平滑地進行連續的部分，則該部分的發光變尸 不均勻’使發光品質下降。 于 由於使擴散板和框部形成一體，所以抑制了擴散板的變 形，並使構件數量減少。另外，由於設置了厚度變化部^ 所以使作用在擴散板上的自重等應力分散，而使擴散 以撓曲。 ” 為讓本發明之上述和其他目的、特徵和優點能更明顯 易丨董’下文特舉較佳實施例，並配合所附圖式，作詳細士、、 明如下。 ΰ、、、田况 【實施方式】 圖1所不為本發明的弟一貫施形恶之液晶顯示普置用 的直下型背光1之概略構成的展開斜視模式圖，圖3為其 斷面圖（與光源10的長邊方向垂直之斷面的斷面圖）。; 直下型背光1包括在上方具有開口部11之箱狀的下框 在該下框2的内部彼此平行配置的多數根光源1〇。另外， 直下型背光1還包括為了堵塞下框2的前述開〇部u而& 該開口部11上配置的擴散板一體框部3、沿該擴散板—體 框部3的外面彼此重疊配置的2張光學片12，13、將這: 光學片12，13中的擴散板一體框部3側的光學片12和^ 散板一體框部3彼此粘著之雙面帶14。 $ 14154pif 8 200530697 下框2和擴散板一體框部3利用未圖示的連結機構被 彼此連結。作為該連結機構，可採用在例如擴散板一體框 部3的侧面16上設有突起部，另一方面，在下框2的内壁 2a上a又有可與前述突起部扣合的扣合孔，並使這些突起部 和扣合孔進行扣合之連結機構，另外也可採用螺旋夾等各 種機構。 另外’作為下框2的材質，適合採用放熱性和機械強 度、形狀穩定性良好的鋁等金屬。而且，在下框2的底面 和光源10之間，為了增強直下型背光1的發光效率並提高 輝度，設置有反射板15。 圖2為從外面側對擴散板一體框部3進行觀察的平面 圖，圖4為圖2的A-A線之斷面圖。如圖4所示，擴散 板-體框部3由絲自統1G的級過並擴散且形成發光 面之擴散板4、在該擴散板4的周麟設置之框部5構成。 框部5較擴散板4厚。而且’擴散板4的外面&為平面。200530697 IX. Description of the invention: [Technical field to which the invention belongs] The present invention relates to a direct type backlight. [Prior Art] Backlights used in liquid crystal display devices and the like are roughly classified into backlights of an edge light type and backlights of a direct type. Among them, the direct type backlight has characteristics such as being suitable for enlargement and easy to obtain high brightness, and therefore, it can be widely used as a large flat light emitting device. In addition, in liquid crystal display devices, direct-type backlights are increasingly used as flat light-emitting devices used for large daytime surfaces of 15 inches or more. A conventional general direct type backlight is described with reference to the drawings. Here, a case where a display portion such as a liquid crystal panel and an optical sheet are used is described as an example. Fig. 7 is a sectional view of a plane orthogonal to the long side of the linear light source 31. As shown in FIG. 7, the backlight is composed of a plurality of light sources (lamps) 31, a lower frame 32 as a cover having an opening portion and an internal light source 31 inside, a reflective layer 33 provided on the inner surface of the lower frame, and a liquid crystal. The frame-shaped upper frame 34 of the display portion such as the panel 40 is configured by an optical sheet 35 and a diffusion plate 36 sandwiched between the upper frame 34 and the lower frame 32. As the light source 31, a cold-cathode tube type fluorescent lamp is used. The upper frame 34 is provided with a resin guide flange 37 for holding a display portion such as a liquid crystal panel. As in the example shown in FIG. 7, in the conventional backlight, the upper frame 34 and the diffuser plate 36 are respectively formed as different members, and the diffuser plate 36 is a separate member. In addition, the thickness of the entire diffuser plate is a flat plate-shaped member (for example, refer to Patent Literature; and Patent Literature 2). 14154pif 5 200530697 [Patent Document 1] Japanese Patent Laid-Open Publication No. 106-162342 [Patent Literature 2] Japanese Patent Laid-Open Publication No. 2002-182184 discloses a conventional direct-type backlight as described above. There is a problem that the diffusion plate is liable to be deformed such as deflection. The deformation is caused by the weight of the diffuser and the effects of external stress, changes in aging, and the influence of heat from the reflector. When deformation such as deflection occurs on the diffuser plate, if deformation or the like occurs on the diffuser plate, the uniformity of the diffusion of the transmitted light decreases, so the light emission quality as a backlight decreases. Further, when a display portion such as a liquid crystal panel and an optical sheet are used, deformation along the diffusion plate may cause deformation in these optical sheets and the liquid crystal panel, resulting in uneven liquid crystal display. In addition, since the upper frame and the like are each integrated with the diffuser plate, there is also a problem that the number of components of the backlight is increased, and the assembly cost is increased due to the increase in the component management cost and the number of backlight assembly processes. SUMMARY OF THE INVENTION An object of the present invention is to provide a direct type backlight which is formed in view of this situation, can suppress the deformation of a diffuser plate, and improves the light emitting quality, and has a small number of components. The direct type backlight of the present invention includes a diffuser plate that transmits and diffuses light emitted from a light source, a diffuser plate integral frame portion integrally formed with a frame portion provided around the diffuser plate, an opening portion in which the diffuser plate is disposed, and A lower frame in which a light source is arranged inside is characterized in that the diffusion plate has a thickness changing portion that continuously increases in thickness from the center side to the peripheral side. 14154pif 6 200530697 The body is formed by one extra body, so the frame, salt, and reinforcement can be used to suppress the deformation of the diffuser plate, and the number of components can be adjusted by the thickness change portion to the self-weight acting on the diffuser plate. Blade administration makes it difficult to flex the diffuser. The thickness of the diffuser plate can also be used only by the aforementioned Korean Ml · Qiu, & ,,,, and the like. The diffuser plate as a whole has a thickness of ^ ° to form a thickness from the central portion to the peripheral portion of the diffuser plate. =? Composition 'Minimizes the deflection of the diffuser. In addition, “light can be obtained with high brightness,” so especially as a video, sound, car, and other diffuser can also use the thickness from the central side to the peripheral side of the thickness change section, thickness-fixed-thickness section The formed structural transmittance becomes constant. 'It is easy to make the brightness uniform. Therefore, when the former is in stock, the thickness change portion is provided at the center peripheral portion.' The brightness of the same thickness portion provided at the thickness change portion becomes = this. At the same time, the thickness of the diffuser plate in the central portion of the diffuser plate can be made uniform, and the thickness change portion can be used to suppress the deflection of the diffuser plate. However, the central portion of the north t used has a higher luminance than the peripheral portion, so that it can be used as an image backlight in particular to obtain high light emission quality. The thickness of the winter expansion board is more than 0.5 mm and less than 5 mm. This is 2 mm 10 ′ 5mm thin, it is not rigid enough to be easily deformed, and at the same time it is severe, and S is not 1, which results in low light emission quality. Moreover, if it is set too large compared to 5 liters and weight, it is easy to produce deflection, and the amount of material used is 14154 pif 200530697, which increases the manufacturing cost. Further, by making the thickness of the diffuser plate in the range of 0.5 m ', it is possible to suppress the thickness difference of the diffuser plate from becoming too large and causing the luminance to become too uneven. f It is preferable that the surface of the diffuser plate described above is smoothly continuous. This is because if there is a portion that does not proceed smoothly, the luminescence of that portion is uneven and the light emission quality is lowered. Since the diffuser plate and the frame are integrated, deformation of the diffuser plate is suppressed and the number of members is reduced. In addition, since the thickness change portion is provided, stresses such as the self-weight acting on the diffusion plate are dispersed, and the diffusion is flexed. In order to make the above and other objects, features, and advantages of the present invention more apparent, Dong's specific examples are given below, and in conjunction with the drawings, detailed explanations are as follows. [Embodiment] FIG. 1 is a developed oblique view of a schematic configuration of a direct-type backlight 1 for a liquid crystal display device that is not conventionally used by a younger person in accordance with the present invention, and FIG. 3 is a cross-sectional view thereof (a length difference with the light source 10). A cross-sectional view of a cross section perpendicular to the side direction) .; The direct type backlight 1 includes a plurality of light sources 10 arranged in parallel with each other inside the lower frame 2 in a box-shaped lower frame having an opening portion 11 on the upper side. The type backlight 1 further includes two diffuser plate integrated frame portions 3 arranged on the opening portion 11 so as to block the aforementioned open portion u of the lower frame 2 and two sheets arranged on top of each other along the outside of the diffuser plate-body frame portion 3. Optical sheets 12, 13, and this: The optical sheet 12 on the side of the diffuser plate integral frame portion 3 in the optical sheets 12, 13 and the double-sided tape 14 on which the diffuser plate integral frame portion 3 is adhered to each other. $ 14154pif 8 200530697 Lower frame 2 and the diffuser plate integrated frame portion 3 are connected to each other by a connecting mechanism (not shown). This coupling mechanism may be provided with a protruding portion on the side surface 16 of the diffuser-integrated frame portion 3, on the other hand, the inner wall 2a of the lower frame 2 has a fastening hole that can be engaged with the protruding portion, and Various mechanisms, such as screw clamps, can be used to connect the protrusions and the fastening holes. In addition, as the material of the lower frame 2, metals such as aluminum, which is excellent in heat dissipation, mechanical strength, and shape stability, are suitable. In addition, a reflection plate 15 is provided between the bottom surface of the lower frame 2 and the light source 10 in order to enhance the luminous efficiency and brightness of the direct-type backlight 1. FIG. 2 is a plan view of the diffuser-integrated frame portion 3 viewed from the outer side. Fig. 4 is a cross-sectional view taken along the line AA in Fig. 2. As shown in Fig. 4, the diffuser plate-body frame portion 3 is diffused by the wire from the 1G level and diffuses to form a light emitting surface. The frame portion 5 provided by Zhou Lin of 4 is formed. The frame portion 5 is thicker than the diffuser plate 4. The outer surface of the diffuser plate 4 is flat.
而且’擴散板4的外面4a為長方开彡，廿你士命—Q 曰金^u 勹贡万小亚形成與液晶顯示裝 置的液晶畫面大致對應的形狀。 框部包括與擴散板4鄰接並設於其周圍，且較擴散 板4的外面4a高出一層之第—高度差部％、設於該第一 而度差部5a的周圍’且較該第—高度差部化高出一層之 弟二尚度差部5b。如圖3的斷面圖所示， 曰 1”，内:的光學12利用第—高度差部 ;片 Ξ㈡差= 光學片12的外側所配置之光學片二 用弟-肉度^ 5b而限制向面内方向的移動。 14154pif 9 200530697 而且，框部5的整體概略形狀為 其外面的四角，設置有沿第二言卢、，A 乂（長方形），但在 的引導突起5〇4個引部％的外周突出設置 高度差部5以周的麵^=^^有沿長方形的第二 背光1上安裝液晶晝面2〇 刀而且，如在直下型 導突起5c的内側，嵌入在 '攻晶顯示裝置，則在該引 20。這樣一來，利用引導二 以假想線表示的液晶畫面 内方向的移動，使液曰奎、e可限制液晶晝面20向面 上。而且，雖然與t曰二如被固定在擴散板-體框部3 引導突起5c内嵌入光學 '=不同’但也可採用在該 制光學片向面内方向的移動之構成並侧丨導突起5c限 這樣’在擴散板_體柄 -體框部3的外側所設置的構光制在該擴散板 面20等）向面内方(先予片i2、13和液晶晝 5c和高度差πΓΓ 限制襄置，設置有引導突起 M d^5a、5b，所以該構件（光學 ί ΐ Γ Γ f ^變得容易安裝。而且，由於這些限制裝置5 开Γ度产部5a、5b)作為擴散板-體框部3而 -體成形，所以與將液晶晝面固定用凸料作為不同構件 、如圖3所示，在2張光學片12、13中，擴散板々側的 光學片12在考慮因熱造成的伸縮而設有一定空隙的狀鲊 下，被收納於第一高度差部5a的高度差内。而且，光學^片 12的外側所配置的光學片13較光學片12面積大，且第二 高度差部5b和光學片〗3由雙面帶14被固定。這樣—來二 進行安裝的情況相比，構件數量減少，且組裝工程也變少。 I4154pif 10 200530697 光學片η發揮作為蓋的機能而覆蓋光學片i2，且 差部5a中’所以可輕鬆地將多“ 先子片口疋在擴政板4的外侧。另外，將多數個光學 習知的擴散板（另成—體）進行固定是困難的。這^ 當擴散板為平板且在末端利用漿糊和枯著劑等進行固定’ 1夺二3的變形(撓曲)會招致光學片的撓曲，而且， 參 =以外’所以具有使紐板增大並使背光自身大型= 樣-部3其全體由朗的樹脂—體成形。這 樣耒’由於擴散板一體框部3為樹脂制， 板4和框部5由相同的樹脂構成，所以擴散 間成可抑制由兩者的收 得到更加有效地抑= 背光的熱難二 =:，比隔熱特性優良，所以 定特別限 ^的透過光擴散機能優良且 =熱特性優良_為佳，鏡而言乳白板色專） 丙场樹脂、聚丙坤樹脂等色為=色) 上框的為=的方法’可使擴散板-體型 14154pif 200530697 如圖4所示，擴散板4及框部5被_體成形 一體框部3中的擴散板4，在其整體範圍内厚度不^一 — 值，由從該擴散板4的中央側向周邊側厚度連續增加) 度變化部h、厚度-定的等厚部t構成。厚度變化部匕設子 於擴散板4的周邊部，等厚部…於厚度變化部h 側（擴散板4的中央側）。結果，擴散板4的斷面形成略呈 形狀（參照圖4)。等厚部^全體為平板狀，而且 =厚。Μ的中心點C(從等厚心的重心垂到擴散板4的外 面4a之垂線和該外面4a的交點），與擴散板*的中 (從擴散板4的重心垂到擴散板4的外面&之垂線和該 面4a的父點）-致。藉此’容易使擴散板4的自 板4的周邊部分均勻地被分散。 5欣 *而且，擴散板4的厚度分布在等厚部鹐最薄， ★化部h的周邊（即擴散板4的周邊）為最厚。而且: 擴散板4的最小厚度U為0.5_以上，且使擴散板更 最大厚度t2為5mm以下。而且，框部5的厚度（最 度）t5較擴散板4的最大厚度t2厚。 旱 如前所述，擴散板4的外面4a為平面，所以藉 政板4的内面4b整體上為非平面，可在擴散板4上加以』 厚變化。由於在擴散板4的表面（外面如及内面仆）: ^有高度差，所以不會產生_高度差造·異常發 向度差在發光面上顯現為筋狀的部分等）。而且，在 4的表面（外® 4a及内® 4b)不單只是沒有高度差:、且敕 體保持平滑地_。即’等厚部t和厚度變化部h的臨 I4l54pif 12 200530697 處平滑地連續，且厚度變化部h的表面（厚度變化部h的 内面及外面）也平滑地連續。另外，圖4為圖2的a —A 線的斷面圖，但與其直交的方向，即圖2的B — B線的斷 面圖（省略圖示）也形成與圖4相同的形狀。即，厚度變 化部h的厚度變化可沿長方形擴散板4的長邊方向及 方向的任一方向進行變化。而且，擴散板4具有凹透 的厚度分布。 另外，如圖4所示，擴散板4使在擴散板4的短邊方 向及長邊方向之任意位置的斷面（與擴散板4的外面如 垂直的斷面）上的斷面形狀，與外面4a垂直且關於通過該 外面4a的斷面線的中心點之直線tx形成線對稱的形狀/ 另外，利用通過擴散板4的中心點c並與擴散板4的外面 4a垂直的任意平面之斷面形狀，通過該中心點並對與外面 4a的斷面線垂直的直線tz形成線對稱。藉此，擴散板々 的厚度分布形成對稱的狀態，所以擴散板4的自重更加均 勻地被分散，並使因該自重造成的擴散板4的變形極其有 效地受到控制，且擴散板4的輝度分布也形成對稱的狀 態，使發光品質提高。 採用如上構成的直下型背光1起到了下面這樣的作用 效果。 因為擴散板4和框部5被一體成形，並利用框部5而 使擴散板4被加強，所以使擴散板4的變形得到抑制。另 外^因為使框部5的厚度（最大厚度）t5較擴散板4的最 大厚度t2厚，所以利用框部5之擴散板4的加強效果更進 14154pif 13 200530697 一步提高。而且，盘框 相比，直下型背光放板4為不同構件的情況 1月光1的構件數量減少。 庫力H利用^度變化部h，作用在擴散板4上的自重等 應力被分散，擴散板4難以產生挽曲。 寺 均:二因藉為二^ 估艘碎吏專厗π和厚度變化部11適當組合，可 度分而曰二，1 和挽曲的控制同時並存，並得到所需的輝 ί“ t設於厚化部h設於擴散板4的周邊部， 央部的輝声鐵:=的中央側’所以擴散板4的中 是對因播^^Γ =句’且能夠抑制擴散板4的撓曲。特別 h薄的、的自重所造成的撓曲，由於較厚度變化部 於配置於擴散板4的中央部，並藉此使該 =21Γ央部輕量化’所以在取得利用厚度變化部h 於分散效果的同時，因擴散板4的自重所造成的 表曲極其有效地得到改善。 邮由於較厚度變化部h薄的等厚部t設於厚度變化 i4的月Ϊ1 則’所以擴散板4内的輝度分布，形成與擴散 立丄々周邊β相比，中央部比較明亮的形態。由於在中央 =較周f部明亮的情況下’發光面具有好看的傾向，所以 务光品質高。特別是在以液晶晝面等放映出圖像的情況 下，使畫面的中央部較周邊部明亮的情況可使圖像好看， 所以可得到特別適合在液晶晝面和液晶電視等中所使用之 圖像顯示裝置用背光的發光品質。 擴政板4的尽度為〇.5mm以上且為5mm以下。在擴散 14I54pif 14 200530697 板4的厚度較〇.5mm薄的情況下，有時擴散板4的剛性不 足而谷易產生變形，或光的擴散不足而使發光品質低下。 而且，在擴散板4的厚度較5mm厚的情況下，有時擴散 板4的自重過大而容易發生撓曲，或材料的使用量過多而 使製造成本上升。在上述的第一實施形態中，使擴散板4 的厚度在0.5mm〜5mm的範圍内，可使上述問題為最小限 度。而且’藉由使擴散板4的厚度為〇.5mm〜5mm的範圍， 可抑制厚度變化部h的擴散板4的厚度差過大而使輝度變 得過度不均勻之問題。 而且 L1為擴政板4的表面平滑地連續，所以可得到 高發光品質。如果存在不平滑地進行連續的部分，則有時 該部分的發光變得特別不均勻，使發光品魏下，但藉由 平⑺地進行連續，可使擴散板4的斷面線上沒有形成角部 的部分（沒有彎曲的部分），所以發光品f提高。像這樣在 本^明中使擴散板4的表面平滑地進行連續為佳，但更佳 ，疋’當考慮利用與擴散板的外面4a垂直的任意平面之擴 ，板4的斷面的輪廓線時，該輪廓線以在該輪廓線上的所 有的點都可引出切線之程度平滑地進行連續為佳。 =知技術中’為了防止因自重等造成之擴散板的棱 進二Πίΐΐ板4的中央部附近設置從内面側對擴散板 丁支持的支持鎖，但在上述的擴散板-體框部3中，由 為最小限度’所以可削減支持銷等 上述習知技術中的上框34 (參關7)，從成本等方面 14154pif 15 200530697 考慮多使用不銹剛和鋁等金屬，但在這種情況下，因光源 特別是電極所散發的熱量，使導熱率比較優良的金屬制框 架的溫度增高。當液晶面板與該金屬制框架接觸時，該部 分之液晶面板的溫度部分性提高，使液晶面板的溫度分布 變得不均勻，所以會在液晶晝面上產生顏色偏離等品質劣 化。藉此，在這種情況下，需要在金屬性框架和液晶面板 之間設置隔熱用樹脂（泡沫樹脂襯墊），並使將液晶面板進 行固疋疋位之引導凸緣也為樹脂制。在像本實施形態那 樣，將含有框部5之擴散板一體框部3利用樹脂進行製作 的情況下，熱傳導率與金屬相比變小。藉此，可形成一種 將液晶面板直接安裝在擴散板一體框部3上之液晶顯示裝 ，，可不需要上述隔熱用樹脂，且可抑制因液晶面板内^ 溫度差所造成之液晶面面的品質劣化。這樣一來，在利用 樹脂形成擴散板一體框部3的情況下，作為液晶顯示用的 直下型背光變得更加適合。 在如圖7所示之習知的背光中，擴散板36和上框％ 各，一體，所以考慮兩者的尺寸公差、收縮率的差異、變 =等，要在兩者間設置一定的間隙（留空量）。因此，除了 背光的尺寸大型化以外，還容易從間隙侵入異物（室塵、 香煙的煙等）。而且，因留空量的設定不佳，有時擴散板 36會產生變形，或擴散板36和上框34互相磨擦而產生傷 痕，或由該互相磨擦所產生的擦屑附著於背光内部而 光品質劣化。 對此，在上述第一實施形態的擴散板一體框部3中， 14l54pif 16 200530697 =於擴散板4的框部5之間沒有間隙，所以異物（室塵、 香煙的煙等）難以侵入背光内部， 内面扑)附著有異物所造成之發二劣 並使直下型背光丨小型化，且也不會產生因留空量設 疋不佳所造成之擴散板4的變形。 而且，在像習知技術（參照圖7)這樣 學,35分別各自獨立，且光學片料固定·在 擴政板36上的情況下，由於要將這些構件進行一 作，所以比較麻煩，而且有可能在擴散板 ^ ϊ物或=35相互間(當光學片35為多數個 ”物。特別疋在交換光源的燈31 _，由於使上框) 片35分別各自被取出，所以除了麻填以外 異物知入的可能性極高。纽，在這種敎下，產 在淨室中進行燈交換等_。如本實施形態所示 擴散板-體框部3上固定光學片12、13,從而可 廷些擴散板-體框部3及光學片12、13， 〇、 燈交換作業㈣料，且在贿交換時不會在^10的 13間或光學片12、13和擴散板4間侵入異物。予 而且，藉由設法適當變化厚度變化部h的厚声八太 或設法適當變化厚度變化部h和等厚部t的配= 光面的輝度分布任意地進行調整。 了對毛 而且，因為擴散板4和框部5為一體，所以 會出現晃蕩不穩的問題，並可將搖動直下型、間不 出的聲音控制在最小限度，形成靜音性高的直下型 14154pif 17 200530697 圖圖5(a)〜（d)為擴散板一體框部3的變形例的斷面 圖5 (a)所示為擴散板4的整體為厚度變化部h的情 況。即，該擴散板4只由從其中央側向周邊側，厚度連^ 增加的厚度變化部h構成。而且，擴散板4的厚度最薄的 部分為擴散板4的中心點c (即從擴散板4的重心 =垂到擴 散板4的外面4a之垂線和該外面4a的交點）的位置。八 彳⑽擴散板的整卿成厚度變化部，所以形成 從擴政板的中央部向周邊部，厚度連續增加之構成 散板的撓曲相最小限度。而且，由於巾央部較周邊部^ =度^所以特別是可作為圖像用的背光而得到高發光口 二散板4的厚度最薄的部分為擴散板4: 中。點e的位置，所以仙在擴散板4 地被分散，因自重所產生的撓曲變少。自重今易均勾 為平:且且=:(:=?’擴散板4的外*4a 卢闽“、政板的内 形成球面狀的曲面。而且， =上==面Γ (在與職4的長邊及短邊平行之 的：面圖)中，内面4b的斷面線在其整個範圍内曲 像這樣’使厚度變化❿的内面的斷面形 狀為曲率-疋的形狀，則作用在擴散板4上的變形鹿 易均勻地進行分散’擴散板4_形抑制效果增強’二4 在圖5(b)的變形例中，使擴散板 化Μ斜面。這樣，厚度變化部h的表面不只為曲面， 14154pif 18 200530697 為平面另外，在利用與擴散板4的外面4a垂直的 面之斷面視圖巾，如為圖5 (b)的斷面_樣， =直線進仃交差的情況，則這2條直賴成的角度Θ在5 為佳’在10度以下為更佳，在5度以下為特佳。這 =^ ’該肖度Θ越大，這2條直線的交關容易產生里 ^光’有時例如在發光畫面上會顯示出條紋，声^ 面^交差部分越接近於平滑狀態’在發“ 圖5 (c)是使擴散板4的全體為厚度變化部h， 2變=部h由位於擴散板4的周邊部並利用彼此1 進仃傾斜的2個平面形成之平面厚度變化部h2、為^ 度變化部h2中所爽持配置的曲面並將構成平面土 部個平面平滑地進行連接之曲面厚度變化 和平面連續之“明:且擴==面也可採用使曲面 砵 貝您構成而且，也可使曲率不同的曲面進 ί接’也需要使擴散板4的表面連續地進行 二==;:但是由於為擴散板4的範圍 且乂^圖5 (d)的變形例中，擴散板4的外面4a為平面， ，散板4的内面4b上，設於擴散板4的周邊部之厚声 h和設於其内側的等厚部（，除了後述的圓形部分又 卜，都形成為平面，但對這2平面的交差所產生的角部 !4154pif 19 200530697 f :以具有—^曲度半徑幻的圓形。即，在前述角部 半徑⑻。利用該半徑（圓形)，可使彼此為平 ^的專尽部t和厚度變化部h平滑地連續。因此，不會在 毛光面上產生條紋，而形成發光品質高的直下型背光1。 β圖6為關於本發明的第二實施形態之直下型背光6的 辦面圖。在該直下型背光6巾，擴散板4具有從其中央側 向周邊側，厚度連續增加之厚度變化部h，且具有與光源 10的位置對應地使擴散板4的厚度局部增加之局部厚壁部 7。在直下型背光6中，因為線狀的光源1〇彼此平行且並 列地5又置’所以局部厚壁部7也對應這些光源1〇的位置而 彼此平行且間隔-定距離進行設置。另外，擴散板4的外 ，4a形成平滑連續的曲面。結果，擴散板4的内面牝的 斷面形狀形成連續的波形形狀。在該圖6的實施形態中， 因，設有局部厚壁部7，所以在擴散板4的—部分中存在 ，散板4的厚度從其中央側向周邊側連續減少的反向變化 邛分g。這樣’本發明在擴散板4的至少一部分中存在前 述^度變化部h即可，也可在擴散板4的一部分中存在反 向變化部分g。在圖6的實施形態中，構成局部厚壁部7 之波形部分的頂點位置及穀底位置，在圖6的斷面時形成 朝向擴散板的外面4a並大致沿凸狀的圓弧（在圖6中以雙 點劃線進行表示）之位置，即使利用反向變化部g，也要 盡可能地不妨礙設置厚度變化部h的效果。 作為擴散板一體框部3的材料特性，以下述這樣的為 佳。首先，以吸水率〇·5%以下，較佳為〇·3%以下的為佳。 !4ΐ54ρίΓ 20 200530697 ’則當在背光的㈣’濕度等環境不同 時，會導致㈣等變形。而且，線膨脹係數在！ & Μ 2 C ，在〇.7χ 1〇, c以下為更佳。如線膨脹率 題。光透過率在鳳以上為佳，在術。以上為^樣= 小則不能確保發光_亮度，使發纽率低下。而且，該 光透過率在8G%以下為佳，在65%以下為更佳。如過大則 有時難以確保發光的均勻性。負重撓曲溫度在,c以 上為佳’在120Q C以上為更佳。如撓曲溫度過小，則因 燈和倒相器產生的熱量，容易產生歪斜和變形。、 在像上述實施形態那樣，擴散板4和框部5由相同的 樹脂形成的情況下，因為框部5由具有光透過性的材料進 行製作’所以根據其厚度、形狀或材料組鱗規格，可產 生框部5也具有透光性的情況。此時有可能因來自該框部 5的透過光而妨礙發光的均勻性，使發光品質劣化。在這 種情況下，藉由在框部5適#設置遮絲置，可防止來自 框部5的光泄漏並使擴散板4的發光均勻化，提高發光品 貝:作為該遮光裝置的例子，可採用遮光材料的塗敷、利 用蒸鑛等金屬薄膜處理或遮光帶（黑色帶等）#。而且， ，可將下框2由遮光性高的材料（金屬和遮光性高的樹脂 等）進行製作，且在下框2上鮮可對框部5的透過光進 行遮光的遮光部等，像這樣在下框2的形狀上下功夫，不 產生來自框部5的不需要的透過光。 而且，藉由使框部5為遮光性高的材料，並使框部5 14154pif 21 200530697 的光透過率較擴散板4的透過率高，可使來自框部5的多 餘1分也抑制透過光。具體而言，可使擴散板4為白色的 树月曰，而使框部5為黑色的樹脂。在這種情況下，兩者的 材料= 且成除了著色用的色粉以外，可採用共同的樹脂，且 使擴散板4和框部5的物性相近為佳。在像這樣使擴散板 ^和框部5的顏色各不相同的情況下，可採用雙色成形或 夕色成幵乂的方法。该雙色成形或多色成形也相當於本發明 所提到的一體成形。 一另外，在上述實施形態中，例示了一種利用液晶面板 及光學片之液晶顯示裝置用的直下型背光丨，但本發明的 直下型月光1當然也可為燈箱(light box)和看片燈(f|im viewer)等。 而且，本發明的厚度變化部h既可只沿單方向（例如 光源10的長邊方向）使厚度變化，也可沿雙方向（例如， 除了光源10的長邊方向以外，還有與光源10的長邊方向 垂直且與擴散板4的外面4a平行的方向）使厚度變化。 雖然本發明已以較佳實施例揭露如上，然其並非用以 限定本發明，任何熟習此技藝者，在不脫離本發明之精神 和範圍内，當可作些許之更動與潤飾，因此本發明之保護 範圍當視後附之申請專利範圍所界定者為準。 【圖式簡單說明】 圖1為本發明的第一實施形態之直下型背光的分解斜 視圖。 圖2為圖1的直下型背光之擴散板一體框部的平面圖。 14154pif 22 200530697 圖3為圖1的直下型背光的斷面圖。 圖4為圖2的A — A線之斷面圖。 圖5 (a)〜（d)全都為擴散板一體框部之變形例的斷 面圖。 圖6為本發明的第二實施形態之直下型背光的斷面圖。 圖7為習知的直下型背光的斷面圖。 【主要元件符號說明】 1 :直下型背光 2 :下框 2a ··内壁 3:擴散板一體框部 4 ·擴散板 4a :擴散板的外面（表面） 4b :擴散板的内面（表面） 5 :框部 5a :第一高度差部 5b :第二高度差部 5c :引導突起 6:直下型背光 7:局部厚壁部 10 :光源 11 :開口部 14154pif 23 200530697 12、13 :光學片 14 :雙面帶 15 :反射板 20 ·液晶晝面 31 :光源 32 :下框 33 :反射層 34 :上框 35 :光學片 36 :擴散板 37 ·•引導凸緣 c :中心點 t :等厚部 tl :擴散板4的最小厚度 t2 :擴散板4的最大厚度 t5 :框部5的厚度 h :厚度變化部 hi :曲面厚度變化部 h2 :平面厚度變化部 g:反向變化部分 k :角部分 14154pif 24Moreover, the outer surface 4a of the 'diffusion plate 4 is a rectangular slit, and it's your life-Q 金 金 ^ u Gong Wan Xiaoya forms a shape that roughly corresponds to the liquid crystal screen of the liquid crystal display device. The frame portion includes a first-height difference portion% adjacent to the diffuser plate 4 and provided around the diffuser plate 4 and one level higher than the outer surface 4a of the diffuser plate 4; -The height difference part becomes higher than the second brother second degree difference part 5b. As shown in the cross-sectional view of FIG. 3, "1", the inner: the optical 12 uses the first height difference; the film difference = the optical sheet arranged on the outer side of the optical sheet 12 is limited by the degree of flesh ^ 5b 14154pif 9 200530697 In addition, the overall outline of the frame part 5 is the four corners of the outer part, and is provided along the second line, A 乂 (rectangular), but the guide protrusions at the 504 lead The height difference part 5 is protruded from the outer periphery of the part%. The peripheral surface ^ = ^^ has a liquid crystal daylight surface 20 mounted on the rectangular second backlight 1 and is embedded in the 'attachment', such as inside the straight guide protrusion 5c. The crystal display device is in the lead 20. In this way, by using the guide 2 to move in the direction of the liquid crystal screen indicated by the imaginary line, the liquid crystal surface e can limit the liquid crystal day surface 20 to the surface. For example, if it is fixed in the diffuser plate-body frame 3, the guide protrusion 5c is embedded with optical '= different', but it can also adopt a configuration in which the optical sheet is moved in the plane direction, and the guide protrusion 5c is limited in this way. Diffuser_body handle-body frame part 3 0, etc.) inward (the pre-sheets i2, 13 and the liquid crystal day 5c and the height difference πΓΓ are restricted, and the guide protrusions M d ^ 5a, 5b are provided, so this member (optical ί ΐ Γ Γ f ^ becomes It is easy to install. Moreover, since these restricting devices 5 are formed as the diffuser-body frame portion 3, they are formed separately from the liquid crystal daytime surface fixing projections, as shown in Fig. 3. It is shown that among the two optical sheets 12, 13, the optical sheet 12 on the diffuser side 々 is accommodated in the height difference of the first height difference part 5a in a state where a certain gap is provided in consideration of expansion and contraction due to heat. Moreover, the optical sheet 13 disposed outside the optical sheet 12 has a larger area than the optical sheet 12, and the second height difference portion 5b and the optical sheet 3 are fixed by the double-sided tape 14. In this case, the case of the second installation Compared with this, the number of components is reduced, and the assembly process is also reduced. I4154pif 10 200530697 The optical sheet η functions as a cover to cover the optical sheet i2, and the difference 5a 'can easily be used to expand the opening of the multiplier sheet. The outside of the politic plate 4. In addition, the majority of the light diffusion plate It is difficult to fix it. When the diffuser plate is a flat plate and fixed at the end with paste and a desiccant, the deformation (deflection) of 1 to 2 will cause the optical sheet to flex, and, = Beyond ', so that the button plate is enlarged and the backlight itself is large = The sample-section 3 is entirely formed of a long resin body. In this way, because the diffuser-integrated frame section 3 is made of resin, the plate 4 and the frame section 5 are made of resin. The same resin composition, so that the diffusion interstitial can be suppressed more effectively by the two. = The heat of the backlight is difficult. =: Because it has better heat insulation properties, it has a particularly limited ^ transmission light diffusion function and is good for heat. Excellent characteristics _ is better, the mirror is milky white color)) C-field resin, polypropylene resin and other colors = =) The method of the upper frame = = can make the diffuser plate-body size 14154pif 200530697 as shown in Figure 4, diffuse The thickness of the diffusion plate 4 in the plate 4 and the frame portion 5 in the integrally formed frame portion 3 is not uniform throughout the entire range, and the thickness is continuously increased from the center side to the peripheral side of the diffusion plate 4). The part h and the thickness-constant constant thickness part t are comprised. The thickness change portion is provided at the peripheral portion of the diffuser plate 4, and the equal-thickness portion is provided on the thickness change portion h side (the center side of the diffuser plate 4). As a result, the cross-section of the diffuser plate 4 is slightly shaped (see Fig. 4). The equal-thickness portion ^ is generally flat and thick. The center point C of M (the perpendicular from the center of gravity of the center of gravity to the outer face 4a of the diffuser plate 4 and the intersection of the outer face 4a), and the middle of the diffuser plate * (from the center of gravity of the diffuser plate 4 to the outer face of the diffuser plate 4) & the vertical line and the parent point of the face 4a)-to. This makes it easy to uniformly disperse the peripheral portion of the diffusion plate 4 from the plate 4. 5 欣 * Moreover, the thickness distribution of the diffusion plate 4 is the thinnest in the equal-thickness portion, and the periphery of the chemical conversion portion h (that is, the periphery of the diffusion plate 4) is the thickest. Further, the minimum thickness U of the diffusion plate 4 is 0.5 mm or more, and the maximum thickness t2 of the diffusion plate is 5 mm or less. The thickness (maximum) t5 of the frame portion 5 is thicker than the maximum thickness t2 of the diffuser plate 4. As described above, the outer surface 4a of the diffusion plate 4 is flat, so the inner surface 4b of the borrowing plate 4 is non-planar as a whole, and the thickness of the diffusion plate 4 can be changed. Since there is a height difference on the surface of the diffuser plate 4 (the outer surface is like the inner surface), there will be no difference in height, abnormality, and the like. Moreover, on the surface of 4 (outer ® 4a and inner ® 4b), not only is there no difference in height: and the carcass remains smooth_. That is, the locations of the 'equivalent thickness portion t and the thickness change portion h are smooth and continuous at I4l54pif 12 200530697, and the surface of the thickness change portion h (the inner surface and the outer surface of the thickness change portion h) is also smoothly continuous. 4 is a cross-sectional view taken along the line A-A in FIG. 2, but a direction orthogonal to the cross-section, that is, a cross-sectional view taken along the line B-B in FIG. 2 (not shown) is formed in the same shape as in FIG. 4. That is, the thickness change of the thickness changing portion h may be changed in either the longitudinal direction or the direction of the rectangular diffuser 4. Moreover, the diffuser plate 4 has a concave thickness distribution. In addition, as shown in FIG. 4, the diffuser plate 4 has a cross-sectional shape in a cross section (such as a cross section perpendicular to the outer surface of the diffuser plate 4) at any position in the short and long sides of the diffuser plate 4 and The outer surface 4a is perpendicular to the line tx passing through the center point of the cross-section line of the outer surface 4a to form a line-symmetric shape. In addition, an arbitrary plane passing through the center point c of the diffusion plate 4 and perpendicular to the outer surface 4a of the diffusion plate 4 is used. The plane shape passes through the center point and forms a line symmetry with respect to the straight line tz perpendicular to the section line of the outer surface 4a. Thereby, the thickness distribution of the diffuser plate 々 is in a symmetrical state, so the self-weight of the diffuser plate 4 is more uniformly dispersed, and the deformation of the diffuser plate 4 due to the self-weight is extremely effectively controlled, and the brightness of the diffuser plate 4 is controlled. The distribution also forms a symmetrical state, which improves the luminous quality. The direct-type backlight 1 configured as above has the following effects. Since the diffusion plate 4 and the frame portion 5 are integrally formed, and the diffusion plate 4 is reinforced by the frame portion 5, deformation of the diffusion plate 4 is suppressed. In addition, since the thickness (maximum thickness) t5 of the frame portion 5 is made thicker than the maximum thickness t2 of the diffusion plate 4, the reinforcing effect of the diffusion plate 4 using the frame portion 5 is further improved by 14154 pif 13 200530697. Moreover, compared to the case of the chassis, the case where the direct type backlight placing plate 4 is a different component 1 The number of components of Moonlight 1 is reduced. In the coercive force H, stresses such as the self-weight acting on the diffusion plate 4 are dispersed by the degree change portion h, and it is difficult for the diffusion plate 4 to buckle. Temples: Two due to the appropriate combination of 厗 π and 变化 11, which can be divided into two, 1 and 1 coexist with the control of the elbow, and get the required radiance. The thickening portion h is provided at the peripheral portion of the diffuser plate 4, and the glow iron in the central portion: = the center side of the diffuser plate 4. Therefore, the middle of the diffuser plate 4. In particular, the deflection due to the thin and self-weight has a relatively large thickness change portion disposed in the central portion of the diffuser plate 4 and thereby reducing the weight of this = 21Γcentral portion. At the same time of the dispersion effect, the surface curvature caused by the weight of the diffuser plate 4 is extremely effectively improved. Since the post is thinner than the thickness change portion h and is of equal thickness t is provided at the thickness change i4, the diffuser plate 4 The internal luminance distribution is brighter in the center than in the periphery β of the diffused riser. Since the light-emitting surface tends to look good when the center = is brighter than the peripheral f, the quality of the light is high. Especially When an image is displayed on a liquid crystal surface, etc., the center of the screen The bright surrounding area makes the image look good, so it is possible to obtain the light-emission quality that is particularly suitable for backlights of image display devices used in LCD daylight and LCD TVs. The extent of the expansion panel 4 is 0.5 mm or more. The thickness is less than 5 mm. When the thickness of the diffuser 14I54pif 14 200530697 is thinner than 0.5 mm, the rigidity of the diffuser plate 4 may be insufficient, and the valley may be easily deformed, or the light diffusion may be insufficient to reduce the light emitting quality. When the thickness of the diffusion plate 4 is thicker than 5 mm, the weight of the diffusion plate 4 may be excessively large, which may easily cause deflection, or the amount of material used may increase the manufacturing cost. In the first embodiment described above, the diffusion is performed. The thickness of the plate 4 is in the range of 0.5 mm to 5 mm, which can minimize the above problems. Also, by making the thickness of the diffusion plate 4 in the range of 0.5 mm to 5 mm, the diffusion plate 4 having the thickness change portion h can be suppressed. The thickness difference is too large and the brightness becomes excessively non-uniform. Furthermore, L1 is the surface of the expansion panel 4 that is smooth and continuous, so high luminous quality can be obtained. If there is a part that is not smoothly continuous, there is a problem The light emission in this part becomes particularly uneven, which makes the light emitting product lower. However, by continuously carrying out the flat surface, there can be no corner portion (no curved portion) formed on the cross section of the diffusion plate 4, so the light emitting product f is improved. It is better to make the surface of the diffuser plate 4 smoothly and continuously in this specification, but it is even better. When considering the use of any plane perpendicular to the outer surface 4a of the diffuser plate, the cross section of the plate 4 In the case of a contour line, it is better that the contour line is continuously continuous so that all the points on the contour line can be drawn to the tangent line. In the known technology, in order to prevent the edge of the diffusion plate from being caused by its own weight, etc. A support lock for supporting the diffuser plate from the inner side is provided near the central portion of 4. However, the diffuser plate-body frame portion 3 described above is minimized. Therefore, the upper frame of the conventional technique such as a support pin can be reduced. 34 (Reference 7), 14154pif 15 200530697 Considering the use of stainless steel and aluminum, etc., but in this case, due to the heat emitted from the light source, especially the electrode, the metal is made of excellent thermal conductivity frame Increased temperature. When the liquid crystal panel comes into contact with the metal frame, the temperature of the liquid crystal panel in that part is partially increased, and the temperature distribution of the liquid crystal panel becomes uneven, so that quality deterioration such as color deviation occurs on the liquid crystal surface. Therefore, in this case, it is necessary to provide a heat-insulating resin (foam resin gasket) between the metallic frame and the liquid crystal panel, and also make the guide flange for holding the liquid crystal panel in a resin position. When the diffuser-plate-integrated frame portion 3 including the frame portion 5 is made of resin as in this embodiment, the thermal conductivity becomes smaller than that of metal. Thereby, a liquid crystal display device in which a liquid crystal panel is directly mounted on the diffuser integrated frame portion 3 can be formed, the above-mentioned resin for heat insulation can be eliminated, and the liquid crystal surface caused by the temperature difference in the liquid crystal panel can be suppressed. Quality deterioration. In this way, when the diffuser plate integrated frame portion 3 is formed of a resin, it is more suitable as a direct type backlight for a liquid crystal display. In the conventional backlight shown in FIG. 7, the diffuser plate 36 and the upper frame are each integrated, so taking into account the dimensional tolerance, the difference in shrinkage, and the change, etc., a certain gap must be set between the two. (Leave blank amount). Therefore, in addition to the increase in the size of the backlight, foreign objects (room dust, cigarette smoke, etc.) are easily penetrated from the gap. In addition, due to the poor setting of the blanking amount, the diffuser plate 36 may be deformed, or the diffuser plate 36 and the upper frame 34 may rub against each other to cause scratches, or the scraps generated by the mutual friction may adhere to the interior of the backlight and cause light. Quality deterioration. In contrast, in the diffuser plate integrated frame portion 3 of the first embodiment described above, 14l54pif 16 200530697 = there is no gap between the frame portions 5 of the diffuser plate 4, so it is difficult for foreign matter (room dust, cigarette smoke, etc.) to enter the backlight. (Inside flutter) The second-generation hairpin caused by the attachment of foreign matter makes the direct-lit backlight compact and reduces the deformation of the diffuser plate 4 caused by the poor setting of the empty space. Moreover, in the case of the conventional technology (refer to FIG. 7), 35 is independent of each other, and the optical sheet is fixed on the expansion board 36. Since these components are made together, it is troublesome, and It is possible that the diffuser plate ^ ϊ objects or = 35 each other (when the optical sheet 35 is a plurality of "objects. Especially when the light source 31_ is exchanged, because the upper frame is used) The pieces 35 are taken out separately, so except for filling The possibility of foreign objects getting in is extremely high. New Zealand, in this case, the lamp is exchanged in the clean room, etc._ As shown in this embodiment, the optical sheets 12, 13 are fixed to the diffuser plate-body frame portion 3, so that These diffuser plates-body frame 3 and optical sheets 12,13, 〇 can be used for lamp exchange operations, and will not invade between ^ 10 of 13 or optical sheets 12, 13 and diffuser 4 during bribe exchange. In addition, the brightness distribution of the smooth surface can be adjusted arbitrarily by trying to appropriately change the thick sound of the thickness change portion h or the thickness distribution of the thickness change portion h and the equal thickness portion t. Since the diffuser plate 4 and the frame portion 5 are integrated, there will be a problem of unstable shaking It is possible to control the straight-down type and the occasional sound to a minimum, and to form a straight-down type with high muteness. 14154pif 17 200530697 Figures 5 (a) to (d) are cross-sections of modification examples of the diffuser integrated frame portion 3 Fig. 5 (a) shows a case where the entire diffuser plate 4 is a thickness change portion h. That is, the diffuser plate 4 is composed of only the thickness change portion h which increases in thickness from the center side to the peripheral side. The thinnest part of the diffuser plate 4 is the position of the center point c of the diffuser plate 4 (that is, from the center of gravity of the diffuser plate 4 = the intersection of the perpendicular line perpendicular to the outer face 4a of the diffuser plate 4 and the outer face 4a). The thickness of the plate is changed into a thickness change part, so the bending phase of the diffuser plate, which continuously increases in thickness from the central part to the peripheral part of the expansion board, is minimal. Moreover, since the central part of the towel is more than the peripheral part ^ = degree ^ In particular, the thinnest part of the diffuser plate 4 which can be obtained as a backlight for an image is the diffuser plate 4: the middle. The position of the point e, so the cents are dispersed in the diffuser plate 4 due to its own weight. The deflection becomes smaller. The self-weight is evenly flat: and == ((: =? ' Outside * 4a Lu Min ", the inside of the politic plate forms a spherical surface. Moreover, = 上 == 面 Γ (in parallel with the long and short sides of Job 4: a surface view), the cross section of the inner surface 4b The line is curved in its entire range like this: 'The thickness of the inner surface changes to the shape of the curvature-the shape of the cross-section, the deformation deer acting on the diffuser plate 4 is easily dispersed uniformly' Reinforcement 'II 4 In the modification of FIG. 5 (b), the diffusion plate is made into a sloped surface. In this way, the surface of the thickness change portion h is not only a curved surface, but 14154pif 18 200530697 is a flat surface. The cross-sectional view of the vertical plane is like the cross-section of Fig. 5 (b). If the straight line enters and intersects, then the two straight angles Θ are preferably 5 and below 10 degrees. More preferably, it is particularly preferable below 5 degrees. This = ^ 'The greater the angle Θ, the intersection of these two straight lines is easy to produce light.' Sometimes, for example, a stripe is displayed on the light-emitting screen, and the closer the ^ surface ^ intersection is to the smooth state, “FIG. 5 (c) shows the entire thickness of the diffuser plate 4 as a thickness-changing portion h, and the second change = part h is a planar thickness-changing portion h2 formed by two planes located at the peripheral portion of the diffuser plate 4 and inclined by one another. The surface thickness of the curved surface configured in the ^ -degree changing section h2 and the planes that make up the flat soil are smoothly connected. The thickness of the curved surface and the plane continuity "Ming: and the expansion == surface can also be used to make the curved surface The structure can also be used to connect curved surfaces with different curvatures. It is also necessary to continuously perform the two surfaces of the diffuser plate 4 ==; However, since it is the range of the diffuser plate 4 and 乂 ^ 5 in the modified example of FIG. 5 (d) The outer surface 4a of the diffuser plate 4 is a flat surface. On the inner surface 4b of the diffuser plate 4, a thick sound h provided at the peripheral portion of the diffuser plate 4 and an equal-thickness portion provided at the inner side thereof (except for the circular portion described later) , Are formed as planes, but the corners generated by the intersection of these 2 planes! 4154pif 19 200530697 f: to have The radius of curvature is a magic circle. That is, the radius ⑻ at the aforementioned corners. With this radius (circle), the dedicated portion t and the thickness change portion h that are flat with each other can be smoothly continuous. Streaks are generated on the matte surface to form a direct-type backlight 1 with high light-emitting quality. Β FIG. 6 is a schematic view of a direct-type backlight 6 according to a second embodiment of the present invention. The plate 4 has a thickness changing portion h that continuously increases in thickness from its center side to its peripheral side, and a locally thick wall portion 7 that locally increases the thickness of the diffuser plate 4 in accordance with the position of the light source 10. In the direct type backlight 6, Because the linear light sources 10 are parallel to each other and are placed side by side 5, the local thick-walled portions 7 are also arranged parallel to each other and spaced apart from each other in accordance with the positions of these light sources 10. In addition, outside the diffusion plate 4, 4a forms a smooth and continuous curved surface. As a result, the cross-sectional shape of the inner surface 牝 of the diffuser plate 4 forms a continuous wave shape. In the embodiment of FIG. 6, since a thick portion 7 is provided locally, — Present in part, thickness of loose plate 4 The central side to the peripheral side continuously decrease the reverse change factor g. In this way, the present invention suffices to include the aforementioned degree change portion h in at least a portion of the diffuser plate 4, and may also include a reverse in a portion of the diffuser plate 4. Changed part g. In the embodiment of FIG. 6, the apex positions and trough positions of the corrugated portions constituting the local thick-walled portion 7 are formed along the convex circle toward the outer surface 4 a of the diffuser plate in the cross section of FIG. 6. The position of the arc (indicated by a two-dot chain line in FIG. 6) does not hinder the effect of providing the thickness change portion h as much as possible even if the reverse change portion g is used. Material characteristics as the diffuser integrated frame portion 3 The following is preferred. First, the water absorption is preferably 0.5% or less, and more preferably 0.3% or less. ! 4ΐ54ρίΓ 20 200530697 ’When the environment such as ㈣’ humidity in the backlight is different, it will cause deformation such as ㈣. Moreover, the coefficient of linear expansion is! & M 2 C, more preferably 0.7 x 10, c. Such as linear expansion rate. The light transmittance is better than Feng. The above is ^ sample = small can not ensure the luminous_brightness, making the button rate low. The light transmittance is preferably 8G% or less, and more preferably 65% or less. If it is too large, it may be difficult to ensure uniform light emission. The deflection temperature under load is preferably above c, and more preferably above 120Q C. If the deflection temperature is too small, it is easy to be skewed and deformed due to the heat generated by the lamp and the inverter. In the case where the diffuser 4 and the frame 5 are formed of the same resin as in the above-mentioned embodiment, the frame 5 is made of a material having light permeability, so according to the thickness, shape, or scale of the material group, The frame portion 5 may have a light-transmitting property. In this case, the uniformity of light emission may be hindered by the transmitted light from the frame portion 5 and the light emission quality may be deteriorated. In this case, by providing a shield in the frame portion 5, light leakage from the frame portion 5 can be prevented and the light emission of the diffuser plate 4 can be made uniform, thereby improving the light emitting product. As an example of the light shielding device, Can use the coating of light-shielding materials, treatment with metal thin films such as steam ore, or light-shielding tape (black belt, etc.) #. In addition, the lower frame 2 can be made of a material with high light-shielding properties (metal, resin with high light-shielding properties, etc.), and a light-shielding portion or the like that can shield light transmitted through the frame portion 5 on the lower frame 2 is like this Efforts were made to shape the lower frame 2 so that unnecessary transmitted light from the frame portion 5 was not generated. In addition, by making the frame portion 5 a material having high light-shielding properties and making the frame portion 5 14154pif 21 200530697 have a higher light transmittance than that of the diffuser plate 4, the extra one point from the frame portion 5 can also suppress transmitted light. . Specifically, the diffuser plate 4 can be made of a white tree, and the frame portion 5 can be made of a black resin. In this case, the material of the two is equal to the toner used for coloring, and a common resin can be used, and the physical properties of the diffusion plate 4 and the frame portion 5 are preferably similar. When the colors of the diffuser plate 15 and the frame portion 5 are different from each other in this manner, a two-color molding method or an evening color molding method can be adopted. This two-color molding or multi-color molding also corresponds to the integral molding mentioned in the present invention. In addition, in the above embodiment, a direct type backlight for a liquid crystal display device using a liquid crystal panel and an optical sheet was exemplified. However, the direct type moonlight 1 of the present invention may of course be a light box and a viewing light. (f | im viewer), etc. In addition, the thickness changing portion h of the present invention may change the thickness only in one direction (for example, the long-side direction of the light source 10) or in two directions (for example, in addition to the long-side direction of the light source 10), (The direction of the long side is perpendicular to the direction parallel to the outer surface 4a of the diffuser plate 4). Although the present invention has been disclosed in the preferred embodiment as above, it is not intended to limit the present invention. Any person skilled in the art can make some modifications and retouching without departing from the spirit and scope of the present invention. Therefore, the present invention The scope of protection shall be determined by the scope of the attached patent application. [Brief description of the drawings] Fig. 1 is an exploded perspective view of a direct type backlight according to a first embodiment of the present invention. FIG. 2 is a plan view of an integral frame portion of a diffuser plate of the direct type backlight of FIG. 1. 14154pif 22 200530697 FIG. 3 is a sectional view of the direct type backlight of FIG. 1. Fig. 4 is a sectional view taken along the line A-A in Fig. 2. Figs. 5 (a) to (d) are sectional views each showing a modified example of the integral frame portion of the diffuser plate. 6 is a cross-sectional view of a direct type backlight according to a second embodiment of the present invention. Fig. 7 is a sectional view of a conventional direct type backlight. [Description of main component symbols] 1: Direct-type backlight 2: Lower frame 2a · · Inner wall 3: Diffusion plate integrated frame part 4 · Diffusion plate 4a: Outer surface (surface) of the diffuser 4b: Inner surface (surface) of the diffuser 5: Frame part 5a: first height difference part 5b: second height difference part 5c: guide protrusion 6: direct type backlight 7: partially thick-walled part 10: light source 11: opening 14154pif 23 200530697 12, 13: optical sheet 14: double Surface band 15: Reflective plate 20 Liquid crystal day 31: Light source 32: Lower frame 33: Reflective layer 34: Upper frame 35: Optical sheet 36: Diffusion plate 37 : Minimum thickness t2 of the diffuser plate 4: maximum thickness t5 of the diffuser plate 4: thickness of the frame portion h: thickness change portion hi: curved surface thickness change portion h2: planar thickness change portion g: reverse change portion k: corner portion 14154 pif twenty four