TW200843934A - Mold for forming light guide plate and forming method - Google Patents

Mold for forming light guide plate and forming method Download PDF

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Publication number
TW200843934A
TW200843934A TW96128222A TW96128222A TW200843934A TW 200843934 A TW200843934 A TW 200843934A TW 96128222 A TW96128222 A TW 96128222A TW 96128222 A TW96128222 A TW 96128222A TW 200843934 A TW200843934 A TW 200843934A
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Taiwan
Prior art keywords
light guide
forming
guide plate
mold
runner
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TW96128222A
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Chinese (zh)
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TWI318166B (en
Inventor
Toshiyuki Ebina
Takashi Kazuguchi
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Meiki Seisakusho Kk
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Priority to JP2007129670 priority Critical
Priority to JP2007185124A priority patent/JP4047917B1/en
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Publication of TW200843934A publication Critical patent/TW200843934A/en
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Publication of TWI318166B publication Critical patent/TWI318166B/zh

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Abstract

Upon injection molding, in order to inject resin at high speed to fill up a thin mold cavity having thickness approximately identical to that of a light guide plate, the diameter of a runner has to be enlarged to reduce flowability loss of the molten resin, and the mold cavity and the runner are in need holding pressure. Consequently, the problem that the consumed time for fully cooling and curing the runner is too long has occurred. The present invention is proposed for solving this problem. The runner bush 44 of the mold 11 of this invention for forming the light guide plate is connected, via flow passage forming parts 32, 54, to a volume variable mold cavity forming parts 16a, 42a, of which the injection hole 44c has a diameter P1a of 1.6 to 2.6 mm, the flow passage connecting part 44d has a diameter P1b less than 3.6 mm, and which has an inner hole 44a with an inclined ejection angle with respect to a central line and an independent cooling medium flow passage 51 therearound. A light guide plate P, P with a product volume less than 7.8 cm<SP>3</SP> is molded by the forming mold 11.

Description

200843934 (1) 九、發明說明 【發明所屬之技術領域】 本發明係關於導光板之成形模具以及成形方法,特別 是關於在澆道(sprue)部分的形狀及澆道部分的成形進行改 良之導光板之成形模具以及成形方法。 【先前技術】 關於以射出成形來成形出導光板之方法,大致可分 成:專利文獻1所記載之使用設有熱流道(hot runner)的 成形模具之方法、專利文獻2所記載之使用設有冷流道 (包含澆道)之成形模具之方法。前者之設有熱流道之成形 模具,雖有樹脂之成形損失少之優點,但存在有以下的缺 點。 (1) 模具構造複雜。 (2) 成形開始時的調整很耗時間。 (3) 射出時之流動損失大。 (4) 因爲模穴之噴嘴附近不容易冷卻,故成形循環時 間變長。 因此,雖可使用於澆道及流道全長夠長之大型導光板 的射出成形,但在小型導光板(7吋以下)的情形幾乎不使 用。 後者之設有冷流道之成形模具,在由流道及澆道所構 成之冷流道部分會發生樹脂之成形損失的問題’但因模具 構造比較簡單且成形開始前之調整容易,因此被廣泛的使 -4- 200843934 (2) 用。專利文獻2所記載的構造,係稱作所謂3片板片的方 式,可從板片3 2、3 3之間取出流道。在板片3 2上設有澆 道專用之冷卻配管,可有效地冷卻澆道以縮短冷卻步驟的 時間。然而專利文獻2所記載的方式,其模具構造複雜而 僅適用於大型導光板之成形。且基於以下理由並無法大幅 縮短冷卻時間。 (1) 由於是使用射出成形模具(合模時之模穴容積一定) 來進行成形,必須將樹脂射出充塡至和導光板的板厚大致 相等之模穴內。因此,必須以高速的射出速度將樹脂射出 充塡至模穴內,才能使熔融樹脂均一地充塡至導光板端 部。爲了使熔融樹脂維持高速的射出速度到達模穴內,熔 融樹脂之流動損失必須儘量減少,故必須將澆道的直徑加 大。 (2) 由於流道呈彎曲狀,故熔融樹脂之流動損失大, 爲了解決此問題,必須將澆道及流道之直徑進一步加大。 (3 )爲了防止模穴內之熔融樹脂收縮所造成之凹陷 (sink),必須將射出裝置持續保壓,結果,澆道部分在高 壓下是以未收縮的方式成形,因此澆道內壁和澆道之脫模 變困難。 因此在專利文獻2中,即使設有澆道專用的冷卻配 管,基於前述(1)(2)的理由不得不加大澆道的直徑,因此 迄完全冷卻硬化爲止必須花費長時間,又基於前述(3 )的 理由,在拔取澆道時,爲了防止澆道切斷而殘存於澆道襯 套的內孔,存在著必須將澆道冷卻至更低溫之問題點。 -5- 200843934200843934 (1) IX. DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a forming mold and a forming method for a light guide plate, and more particularly to an improvement of the shape of a sprue portion and the formation of a sprue portion. Forming die for light plate and forming method. [Prior Art] The method of forming a light guide plate by injection molding is roughly classified into a method of using a mold having a hot runner described in Patent Document 1, and a use described in Patent Document 2 A method of forming a mold for a cold runner (including a runner). The former mold having a hot runner has the advantages of less loss of resin formation, but has the following disadvantages. (1) The mold structure is complicated. (2) Adjustment at the start of forming is time consuming. (3) The flow loss at the time of injection is large. (4) Since the vicinity of the nozzle of the cavity is not easily cooled, the molding cycle time becomes long. Therefore, it is possible to mold and shape a large-sized light guide plate having a long runner and a long runner, but it is hardly used in a small light guide plate (below 7 inches). In the latter, a molding die provided with a cold runner causes a problem of loss of resin formation in a cold runner portion composed of a runner and a runner. However, since the mold structure is relatively simple and the adjustment before the start of molding is easy, Extensive use of -4- 200843934 (2). The structure described in Patent Document 2 is a so-called three-piece sheet, and the flow path can be taken out from between the sheets 3 2 and 3 3 . A runner-specific cooling pipe is provided on the plate 3 2 to effectively cool the runner to shorten the cooling step time. However, the method described in Patent Document 2 has a complicated mold structure and is only suitable for forming a large light guide plate. The cooling time cannot be significantly shortened for the following reasons. (1) Since the injection molding die is used (the cavity volume at the time of mold clamping is constant), the resin must be injected into the cavity which is substantially equal to the thickness of the light guide plate. Therefore, it is necessary to charge the resin into the cavity at a high-speed ejection speed so that the molten resin is uniformly charged to the end of the light guide plate. In order to maintain the high-speed injection speed of the molten resin into the cavity, the flow loss of the molten resin must be minimized, so the diameter of the runner must be increased. (2) Since the flow path is curved, the flow loss of the molten resin is large, and in order to solve this problem, the diameter of the runner and the flow path must be further increased. (3) In order to prevent the sink caused by the shrinkage of the molten resin in the cavity, the injection device must be kept under pressure, and as a result, the runner portion is formed in an uncontracted manner under high pressure, so the inner wall of the runner The demoulding of the runner becomes difficult. Therefore, in Patent Document 2, even if a cooling pipe dedicated to a runner is provided, the diameter of the runner has to be increased for the reason of the above (1) and (2). Therefore, it takes a long time to completely cool and harden, and it is based on the foregoing. The reason for (3) is that when the runner is taken out, in order to prevent the runner from being cut and remaining in the inner hole of the sprue bushing, there is a problem that the runner must be cooled to a lower temperature. -5- 200843934
在專利文獻 3揭示的例子中,在成形出厚度 0 · 6 5 m m、對角尺寸 1 〇· 6 吋之導光板時,必須使用 5 0 0 m m / s e c以上的射出速度。在專利文獻3,對於1次射 出(one shot)重量之65g,成形品重量爲29g,成形品重量 比爲44.6%。參照其第1圖可知,專利文獻3屬於無流道 之直接澆口型,因此澆道重量比爲5 0 %以上。亦即,爲了 確保前述射出速度,必須加大澆道截面積,基於前述說明 可知澆道部分的重量會變重。附帶一提,在專利文獻2、 專利文獻3中雖然完全沒有提到成形循環時間等,但具備 前述般之澆道的情形,根據常識判斷必須20秒以上的成 形循環時間。 在專利文獻4中,係使用在澆道具備澆道襯套(和射 出成形用噴嘴接觸的部位之有效直徑爲1〜l〇mm)之射出 成形用模具來進行導光板等的成形。在專利文獻4之實施 例1,係以循環時間 40秒爲目標,來進行板厚 2.0〜 6.0mm之楔形導光板的成形。然而在專利文獻4中,係使 用射出成形模具(合模時之模穴容積一定)來進行成形,必 須將樹脂射出充塡至和導光板的板厚大致相等之模穴內, 雖可形成前述板厚之導光板,但針對板厚較薄的導光板, 要用較低的射出速度來成形出良品會有困難。又關於澆道 襯套和噴嘴的接觸部位之有效直徑,當有效直徑爲3mm 以下時,要成形出板厚0.6mm以下的薄導光板的良品會 有困難。亦即,當澆道襯套之前述有效直徑爲3mm以下 時,即使進行5 00mm/Sec以上之高速射出,要充塡至導光 200843934 (4) 板(薄板厚)的端部會有困難’當射出速度更高速時’殘留 應力會造成導光板發生變形,而有發生亮度分布不均的問 題。因此在專利文獻4,難以適用在澆道內徑較小的部 分,如其第6圖所揭示,僅能適用於澆道和射出成形用噴 嘴的接觸部位的有效直徑爲4 · 2mm左右者。又在專利文 獻4,並未揭示專用於冷卻澆道之調溫配管,應是和其他 部分兼用來進行冷卻,如此並無法將成形品和澆道分別以 適當的溫度進行冷卻。又在專利文獻4中,係使用熱傳導 率3 5 W/m · K以上的材料之澆道襯套來促進冷卻,當澆道 襯套之前述有效直徑爲3 mm以下時,由於局部進行澆道 之冷卻硬化,來自射出裝置之保壓可能不夠完全,成形出 之導光板可能會發生凹陷。再者由於澆道襯套之熱傳導率 高,當噴嘴不斷接觸澆道襯套來進行成形時,噴嘴前端之 熱會喪失過多,因此要求每次成形時都使噴嘴後退,故無 法縮短成形循環時間。 〔專利文獻1〕日本特開2003 - 1 455 93號公報(段落 〔0016〕,第 1 圖) 〔專利文獻2〕日本特開2004-9055 5號公報(申請專 利範圍第1項,第2圖) 〔專利文獻3〕日本特開2006-341512號公報(段落 〔0026〕,第 7 圖) 〔專利文獻4〕日本特開2007-83462號公報(申請專 利範圍第1項,段落〔001 6〕,第6圖) 200843934 (5) 【發明內容】 本發明係有鑑於上述問題點,其目的係提供一種導光 板之成形模具及成形方法,以解決以往之諸問題,亦即, 以往用射出成形來進行導光板的成形時,爲了高速地將樹 脂射出充塡至和導光板的板厚大致相等之薄型模穴內,必 須將澆道的直徑加大以儘量減少熔融樹脂之流動損失,並 必須將模穴及澆道保壓,結果發生澆道完全冷卻硬化所耗 時間過長之問題。同時提供一種導光板之成形模具及成形 方法,即使是使用模具構造簡單、成形開始時容易進行調 整之冷流道形式的導光板成形模具,仍可減少導光板以外 的部分、亦即流道、澆道等造成成形損失的部分之比例, 而能提昇產率。又提供一種即使縮短澆道的冷卻時間仍能 確實地讓澆道脫模之導光板之成形模具及成形方法。 本發明的請求項1所記載之導光板之成形模具,係在 形成於固定模具和可動模具間的模穴形成部內進行導光板 的成形之導光板之成形模具,其特徵在於:係具備:模穴 形成部,可壓縮成形出成形品容積爲7.8cm3以下的導光 板;澆道襯套,經由流道形成部連接於前述模穴形成部, 其注入孔的直徑爲1 · 6〜2 · 6 mm,流道連接部的直徑爲 3 · 6mm以下,且具備對中心線具有脫模傾斜角度之內孔; 冷卻媒體流路,配設於該澆道襯套的周圍,和用來冷卻前 述模穴形成部之冷卻媒體流路分別獨立形成。 本發明之導光板之成形模具以及成形方法,係在形成 於固定模具和可動模具間的模穴形成部內進行導光板的成 -8- (6) (6)200843934 形之導光板之成形模具中,具備:澆道襯套’經由流道形 成部連接於前述模穴形成部,其注入孔的直徑爲1 ·6〜 2.6mm,流道連接部的直徑爲3.6mm以下,且具備對中心 線具有脫模傾斜角度之內孔;冷卻媒體流路,配設於該澆 道襯套的周圍,和用來冷卻前述模穴形成部之冷卻媒體流 路分別獨立形成。由於用該成形模具來壓縮成形出成形品 容積爲7.8cm3以下的導光板,即使澆道變細,仍能對應 於模穴內的熔融樹脂之冷卻收縮而將前述熔融樹脂壓縮, 同時能謀求冷卻時間及成形循環時間之縮短。又能減少導 光板以外的部分、亦即流道、澆道等造成成形損失的部分 之比例,而能提昇產率。 【實施方式】 關於本實施形態之導光板之成形模具和射出成形機, 參照第1圖至第7圖作說明。第1圖係本實施形態的導光 板的射出成形機之前視圖。第2圖係本實施形態的導光板 之成形模具之截面圖,其顯示可動模具停止於開始射出前 的位置的狀態。第3圖係本實施形態的導光板之成形模具 之截面圖,其顯示模穴內的樹脂被壓縮的狀態。第4圖係 本實施形態的導光板之成形模具之截面圖,其顯示澆口被 切斷的狀態。第5圖係第4圖之澆道襯套之主要部分放大 圖。第6圖係本實施形態的導光板之成形方法之流程圖。 第7圖係本實施形態之導光板之成形方法所製得之澆道及 流道之立體圖。第9圖係本實施形態之導光板之成形方法 -9- 200843934 (7) 所製得之澆道之放大側視圖。 本實施形態之射出成形機1,係利用射出後可改變容 積之模穴來進行成形之射出壓縮成形方式、射出模壓成形 方式的成形機。射出成形機1,係將具備加熱筒2a(內設 螺桿)及噴嘴2b之射出裝置3配設於機床4上。在本實施 形態,噴嘴2b之噴嘴孔直徑爲1.5mm。射出裝置3,係 由未圖示之計量機構之計量用伺服馬達及射出機構之射出 用伺服馬達所控制,以控制射出速度、保壓切換位置、保 壓時的壓力、射出量等等。合模裝置5’係在固定盤6(固 定於機床4)和受壓盤7(配設於機床4)之間配設4根繫桿 8,可動盤9以可移動的方式插通於前述繫桿8。在受壓 盤7上,配設用來進行開閉模及合模之合模汽缸1 〇(開閉 模及合模機構),前述合模汽缸1 0之衝柱1 0a固定於可動 盤9的背面。藉由合模汽缸1〇(開閉模及合模機構)來控制 合模時的合模速度、合模力。本實施形態之開閉模及合模 機構,雖是以藉由伺服閥控制之合模汽缸1 〇爲例’但也 可採用藉由伺服馬達與滾珠軸承機構等作動之肘節機構。 導光板之成形模具1 1,係藉由射出模壓成形來成形 出2個均一板厚的行動電話用導光板(平面方向的對角尺 寸4吋(有效面積3.5吋),板厚0.38mm))。以下’將「行 動電話用導光板」簡稱爲「導光板」。射出模壓成形,係 在開始射出前,使可動模具1 2停止在確保一定開模量之 位置A(固定模具13之模穴形成部42a和可動模具12之 模穴形成部1 6 a的距離=導光板P的板厚加上既定量),開 -10- 200843934 (8) 始射出的同時、開始射出後或射出完成後,將模穴1 4內 的熔融樹脂壓縮來進行成形。射出模壓成形,相對於成形 完成後,係以模穴1 4僅稍打開的狀態進行射出,因此其 流動損失比一般射出成形爲少。因此不需要具有高速射出 能力之射出裝置,能以較低速、低壓來射出熔融樹脂。又 由於射出速度較慢,能儘量減少澆口 P3附近之殘留應力 來成形出薄板厚之導光板P。結果,可成形出彎曲極少、 亮度均衡優異之導光板。再者能解決高速射出成形時易發 生之銀紋、黑點等的問題,且溱道及流道可使用截面積較 小者,因此具有能縮短冷卻時間的優點。又在開始射出的 同時或開始射出後,使可動模具1 2朝合模方向移動而將 熔融樹脂壓縮,在模穴1 4之離澆口部較遠的位置能加快 熔融樹脂的流速而避免充塡不足,且能良好地進行微細圖 案的轉印。又在將澆口 P 3切斷後,在通常的射出成形模 具,並無法從射出裝置進行保壓,但在射出模壓成形的情 形,係將模穴1 4內的熔融樹脂壓縮而對應於冷卻硬化所 產生之收縮。又射出模壓成形所使用之模具,也能適用於 射出壓縮成形(相對於合模完成位置,藉由射出使模穴14 稍打開而再度進行壓縮),本發明的對象包含雙方。 第2圖至第4圖係本實施形態之成形模具1 1之截面 圖。成形模具1 1,係由第1模具之可動模具1 2和第2模 具之固定模具1 3所構成,在合模後的兩模具12、1 3之 間’形成2個容積及厚度可改變之模穴1 4。本實施形態 雖顯示出可取出2個的成形模具1 1,但在僅可取出1個 -11 - 200843934 (9) 的情形,澆道P 1的形狀等也能藉由相同之成形模具來進 行成形。安裝於射出成形機1的可動盤9之可動模具12 上,係設有模具本體部1 5、模芯部1 6、可動框部1 9等。 在模具本體部1 5之固定模具側的面之大致中央,固接著 模芯部16。模芯部16之與固定模具13相對向的面,係 形成鏡面,其構成用來形成光出射面之模穴形成部1 6a, 其與導光板P的形狀大致一致而形成含有突起部等之大致 四角形。在模芯部1 6的內部,形成有與前述模穴形成部 1 6a平行之複數個冷卻媒體流路i 7。模芯部之形成模穴形 成部的部分和其他部分,可由獨立的塊體所構成。又關於 模穴形成部1 6a,雖是顯示鏡面的例子,但也能施加凹 點、溝槽、全像圖(hologram)等的圖案加工或是粗面加工 等等,也不排除安裝有壓模者。 在前述模具本體部1 5之固定模具側的面之上下四部 位’形成有凹部,在該凹部內以朝向前述固定模具側的方 式安裝彈簧1 8。前述彈簧1 8之前述固定模具側,係抵接 於可動框部1 9(以包圍模芯部1 6周圍的方式配設)。換言 之,係在可動框部1 9所形成之空洞部中配設模芯部1 6。 藉由前述彈簧1 8,使可動框部1 9全體能相對於模具本體 部1 5及模芯部1 9朝開閉模方向移動。可動框部1 9之與 固定模具1 3相對向的面係構成抵接面1 9 a。在可動框部 1 9之與澆口相對向側,係以拆裝自如的方式配設用來形 成光入射面之光入射面形成塊20。包含光入射面形成塊 2 0之可動框部1 9的前方內側部分,係和模穴形成部1 6 a -12- 200843934 do) 一起構成模穴形成部(用來形成模穴1 4)。第2圖係顯示可 動模具1 2停止於開始射出前的位置之狀態。第3圖顯示 開始射出後模穴1 4、1 4內的熔融樹脂(未圖示)被壓縮的 狀態。第4圖顯示進一步壓縮後將澆口切斷的狀態。第2 圖〜第4圖中,澆道P1的形狀、模芯部1 6和可動框部 1 9的位置關係、彈簧之收縮等,係表現成比實際的情形 誇張。 在模具本體部1 5之可動盤9側安裝隔熱板2 1,在內 部的空間及孔內配設能透過頂出裝置之頂出片進行前後移 動之突出銷23。突出銷23,係配設在貫通於模具本體部 1 5和模芯部1 6的內部之孔內,其前端面對流道形成部 3 2,爲了容易保持澆道P 1及流道P2而設有截面Z字狀 之咬入部23a。爲了驅動突出銷23,係在可動盤9內或在 可動盤9之合模汽缸1 〇的衝柱1 〇a側配設頂出器驅動裝 置。 在模具本體部1 5的內部配設澆口切斷構件24、24。 各個澆口切斷構件24都是長方形的薄板所構成’其前面 係構成澆口形成部,澆口形成部之模穴側的角部’係構成 用來切斷熔融狀態的澆口之澆口切斷具24a。如第4圖所 示,前述澆口切斷構件24之模穴側的側面之一部分’在 澆口切斷後係構成模穴形成部。澆口切斷構件24之尺 寸,在與熔融樹脂的流動方向正交的方向之寬度(澆口寬 度)爲12mm。爲了成形出本實施形態大小的導光板P,前 述寬度宜爲1〇〜20mm’熔融樹脂流動方向的厚度宜爲 -13- (11) 200843934 1.2〜2 · 0mm左右。 爲了驅動澆口切斷構件24,係在可動盤9內或在可 動盤9之衝柱1 〇a側配設澆口切斷具驅動裝置。澆口切斷 具驅動裝置,可使用受伺服閥控制之油壓缸、或是伺服馬 達和滾珠螺桿機構。在使用受伺服閥控制之油壓缸時,利 用速度控制或壓力控制來進行澆口切斷構件24前進時之 閉環控制。藉由彈簧2 5能使澆口切斷構件24後退。 在模芯部16,在與後述之固定模具13的澆道襯套44 及嵌塊43相對向的面,係構成流道形成部3 2。在流道形 成部32,在與澆口切斷構件24之突出銷23側鄰接的部 分係形成凸部,在與澆道襯套44相對向且面對突出銷23 的部分係形成凹部。澆口切斷構件24之澆口形成部,除 突出時以外,係位於比前述凸部更低的位置(可動盤 9 側)。其理由在於,在射出時,在射出裝置的噴嘴之通路 前端硬化的樹脂藉由冷料井(cold slug well)狀的凹部收容 以避免流入模穴14、14,並防止射出壓過度施加於澆口 切斷構件24的前面而發生毛邊等。 流道形成部32,由第7圖之澆道P1及流道P2(和導 光板P、P經澆口切斷而分離)可知,由其與澆道P1的連 接部P2a往澆口 P3的切斷部P2b、P2b係形成寬度越來越 大,在其與澆道P1的連接部P2a之寬度(大致等於突出銷 23的直徑)爲7mm左右,在澆口 P3之切斷部P2b則爲前 述般之12mm,亦即變寬5mm。又其與澆道P1的連接部 P2a之寬度宜爲3〜9mm左右。關於流道P2之板厚2c, -14- (12) 200843934 基於縮短冷卻時間同時確保流動性之觀點’宜爲0 ·6〜 1 .5mm左右。在本實施形態係設計成:流道形成部32構 成模芯部16的一部分,且流道P2及澆口 P3之截面積在 射出後可改變,但也能設計成··流道形成部構成可動框部 的一部分,而流道及澆口的截面積無法改變。又流道及繞 口可呈直線狀連接於模穴,流道的寬度、長度可適當地選 擇,但宜使用膜狀澆口(film gate)。 在突出銷23的周圍,在澆口切斷構件24的附近形成 有冷卻媒體流路3 3,以促進流道P2之冷卻。脫模時進行 噴吹之空氣通路3 4,係形成在模芯部1 6和可動框部1 9 之間。空氣通路也能設置在澆口切斷構件24和孔之間。 當將導光板和澆道等以維持一體的狀態把持澆道而進行取 出時,不須使用澆口切斷構件,因此澆口切斷構件在本發 明並非必須構件。 接著說明固定模具1 3,如第2圖〜第4圖所示,在 ^ 安裝於射出成形機1的固定盤6之固定模具13上,形成 有模具本體部41、模穴形成塊42、嵌塊43、澆道襯套 . 44、澆口切斷構件45、45、抵接塊46等等。在模具本體 部4 1之固定盤側,除安裝有隔熱板4 7,並形成有供射出 裝置3的噴嘴2b插入之孔48,在其周圍安裝定位環49。 在模具本體邰4 1之可動模具側安裝模穴形成塊4 2,該模 穴形成塊42之與可動模具1 2相對向的面,係構成模穴形 成部中之主要部形成部42 a。在本實施形態之該主要部形 成部42a,係形成反射面的部分,其上刻設有微細凹點。 -15- (13) (13)200843934 又在模穴形成塊42的內部,以與前述模穴形成部的迮g 部形成部平行的方式,形成複數個冷卻媒體流g各 50。又在模穴形成塊42及嵌塊43和抵接塊46之間,形 成有用來在脫模時噴吹空氣之空氣通路53。 在模具本體部4 1,配設有模穴形成塊42以及嵌塊 43。如第5圖(將第4圖之二點鏈線部分放大)所示,在嵌 塊43的中央之孔,配設澆道襯套44。澆道襯套44,係以 段部爲邊界,形成有可動模具1 2側之小徑部、噴嘴接觸 面44b側之大徑部,並在中心軸設置用來成形出澆道p &amp; 內孔 44a。澆道襯套 44,係由不鏽鋼(麻田散鐵系 SUS420J2)或硬度相當之鋼所構成。SUS420J2之熱傳導率 爲24.9W/m°C,當澆道襯套44使用熱傳導率太高的材料 時,會使噴嘴前端過度冷卻而對射出造成阻礙,且澆道襯 套44內之熔融樹脂的冷卻硬化進展過快,因此雖非必 須,但各種不鏽鋼之熱傳導率宜在1 3〜3 0 W/m °C的範圍。 不鏽鋼之楊氏模數宜爲180〜210kN/mm2,當楊氏模數過 低時,在持續承受噴嘴接觸力的狀態下可能會發生問題。 澆道襯套44之內孔44a,係從面對噴嘴接觸面44b 之注入孔44c朝流道連接部44d呈錐狀擴大。本實施形態 之脫模傾斜(爲了使澆道脫模所需的傾斜稱作脫模傾斜)的 角度Θ,如第5圖之截面所示,相對於中心線L各爲 1°,兩側爲2°。前述角度宜各爲〇.5〜2.0°(兩側爲1〜 4°),更佳爲各0.8〜1.4°(能獲得流道連接部44d的最佳直 徑),特佳爲1 °。當脫模傾斜角度0小於0.5。時,與內孔 -16- (14) (14)200843934 間的摩擦過大,在進行澆道P 1之脫模時,澆道P 1可能被 切斷,或容易發生牽絲。又當脫模傾斜角度0大於2 · 0 ° 時,流道連接部附近的直徑變得過大,在進行澆道P 1的 脫模時,在流道連接部附近的冷卻變慢,在流道連接部附 近發生澆道P 1切斷的問題。即使脫模傾斜角度0在2°或 2°附近的情形,當澆道P1之流道連接部44d的直徑Plb 超過一定値以上時,仍會發生冷卻時間過長的問題。 本實施形態之澆道襯套44的內孔44a之注入孔44c 的直徑Pla爲2.0mm(截面積3.14mm2,以下四捨五入); 流道連接部 44d 的直徑 Plb 爲約 2.87mm(截面積 6.47mm2,以下四捨五入)。前述注入孔44c的直徑Pla, 係比噴嘴2b之噴嘴孔的直徑(本實施形態爲1.5mm)更 大。當注入孔44c的直徑P 1 a過小時,會導致熔融樹脂之 流動損失’或因澆道過度冷卻而發生問題;當過大時,成 形循環時間變長,又會引起澆道切斷或牽絲。本實施形態 之澆道襯套44的內孔44a的截面形狀爲正圓形,但並不 排除正圓形以外的形狀,因此直徑P 1 a、P 1 b代表有效直 徑。例如注入孔及流道連接部之至少一方爲非正圓形狀 (可爲橢圓形、多角形、圓弧和直線的組合、不同圓弧所 組合成的形狀等等)的情形,只要符合第9圖所示之最 大、最小之澆道襯套44的注入孔44c、流道連接部44d 的截面積範圍內即可。 澆道襯套44的內孔44a的全長Pic,其最佳値爲 25mm。當澆道襯套44的內孔44a的全長Pic較短時,基 -17- (15) (15)200843934 於防止熔融樹脂的流動損失之觀點較爲有利’但爲了在固 定模具13設置冷卻媒體流路50等,嵌塊43必須具備足 以承受噴嘴接觸壓之厚度,因此長度必須爲20mm以上。 又關於澆道襯套44的內孔44a的全長Pic ’爲了減少熔 融樹脂之流動損失必須爲30mm以下。澆道襯套44的內 孔44a的表面,係藉由噴砂來施以粗面加工’以使澆道襯 套44的脫模變容易。 因此在本實施形態,第5圖中,以一點鏈線和流道 P2區隔開,在內孔44a內所成形出之澆道P1的容積,在 不考慮微量凹陷及粗面部分下爲1 16· 6mm3(以下四捨五 入),乘上成形所使用之聚碳酸酯比重1.2,結果澆道P1 重量g2爲0.1 4g(以下四捨五入)。又第7圖所示之澆道 P1加上流道P2的重量(實測値之平均値)爲〇.5〇g’除以 比重所得容積値約416· 7mm3 (以下四捨五入)。因此’本實 施形態之流道P2、P2的重量’在兩側爲〇.36g(計算値)’ 其容積爲 3 00.0mm3(運算値)。對角尺寸 3吋、板厚 0.3mm(均一*板厚)之導光板P成形品1片之重重§1(貫測 値之平均値)爲2.20g,其容積約1 8 3 3.3 mm3(以下四捨五 入)。在本實施形態,由於同時成形出2片導光板’ 2片 導光板P之成形品重量g1爲4.4〇g’容積爲3666.6mm3 (容積3.7cm3,以下四捨五入)。因此,相對於導光板P之 成形品重量gl,澆道襯套44所成形出之澆道P1重量g2 之重量%(計算式g2/gl)爲3·2%(以下四捨五入)。此數 値,相較於藉由習知射出成形(模穴之容積固定)來成形出 -18- (16) (16)200843934 導光板P時澆道P1對導光板p之重量%,僅1/3〜1/6左 右,如此可實現澆道P1之小型化及容積之減少。 第9圖之實線係顯示本實施形態之導光板的成形方法 所製得之澆道的放大截面圖。第9圖之虛線係顯示本發明 所製得的繞道P 1之最小和最大的情形。第9圖之二點鏈 線係顯示習知之導光板的成形方法所製得的澆道,可看出 本發明的澆道P1之容積非常小。又已確認出,本發明之 澆道襯套44可適用於:對角尺寸(實際尺寸)5吋、板厚 0.5mm的導光板(容積3 8 76mm3、重量4.65g)成形出2個 的情形((容積77 5 2mm3 (7.8 cm3(小數點第3位四捨五入)、 重量9.3 g);對角尺寸(實際尺寸)7吋、板厚0.5mm的導 光板(容積7526mm3(7.5cm3(小數點第3位四捨五入)、重 量9.03g)成形出1個的情形。 如上述般,決定本發明之成形循環時間中的冷卻時間 之最有影響力的要素,係如第5圖所示之澆道P1的直徑 及錐角(脫模傾斜角度)(9。射出裝置之噴嘴之噴嘴孔(未 圖示)的直徑爲1 · 5 mm。在進行澆道之脫模時,爲了良好 地除去噴嘴前端之樹脂,澆道襯套44的噴嘴孔側的注入 孔44c的直徑必須比噴嘴孔的直徑更大,宜形成1.6mm 以上的注入孔。第1 0圖至第1 4圖係顯示出,使用能取出 小型導光板(對角尺寸 2.8吋、板厚 0.4mm、容積 0.94cm3)2個之射出壓縮成形裝置(澆道襯套44的構造和 第5圖相同)進行測試的結果,其測試條件爲:用來冷卻 模穴形成面之冷卻媒體流路的冷卻水溫度各90 °C,噴嘴 -19- (17) (17)200843934 溫度3 25 °C,加熱筒前部溫度3 5 5 °C,加熱筒中部溫度 3 70 °C,加熱筒後部溫度3 60°C,射出速度3 00mm/sec。 第1 〇圖係顯示,使用注入孔44c的直徑1.6mm(截面 積2.01mm2,以下四捨五入)、第5圖所示之錐角0爲 1 °、流道連接部44d的直徑2.5mm、長度25mm的澆道襯 套44時之數據。所成形出之澆道P1,係第9圖之最內側 的虛線所記載者。在本例,當澆道襯套44之冷卻溫度爲 70 °C、80 °C的情形,當成形循環時間變長(5秒以上)時澆 道襯套44之注入孔44c及噴嘴之噴嘴孔過度冷卻而發生 下一個射出無法進行、成形品中混入冷料塊(cold slug)等 的問題。當澆道襯套44的冷卻溫度爲90 °C以上的情形, 在6秒以上時也會發生不良。因此,澆道襯套44之注入 孔44c的直徑爲1.6mm時,其實用範圍變得極窄,當其 數値更小時,無法進行符合實用之設定調整。 第1 1圖係顯示,使用注入孔44c的直徑2.0mm、錐 角0爲1 °、流道連接部44d的直徑2.9mm、長度25rnm的 澆道襯套44時之數據。所成形出之澆道P1,係第9圖之 實線所記載者。本例中,各冷卻溫度的情形,當成形循環 時間爲2秒時,可能會發生澆道P 1之冷卻跟不上、湊道 切斷的情形,但除此之外的結果良好。然而當成形循環時 間超過一定以上時經濟性不佳。又當成形循環時間過度延 長時會發生:噴嘴被冷卻而使熔融樹脂的流動性變差、加 熱筒內之熔融樹脂的滯留時間過長而造成樹脂劣化(黃 變、黑點)等的問題。關於冷卻水的溫度,在4〇 〇c的情 -20- 200843934 (18) 形,由於成形品中會混入冷料塊,故成形採用之冷卻溫度 宜爲5 0 °C以上。又在1 2 0。(:的情形,在4秒時會發生澆道 切斷,因此成形採用之冷卻溫度宜爲1 1 0 °C以下(特別是 模穴形成面的冷卻溫度以下)。 第12圖係顯示,使用注入孔44c的直徑2.3mm、錐 角0爲1°、流道連接部44d的直徑3.2mm、長度25mm的 澆道襯套44時之數據。在本例,當冷卻溫度爲70 °C的情 形,在成形循環時間3秒時會發生澆道切斷,在冷卻溫度 8 0 °C、9 0 °C的情形,在成形循環時間5秒時會發生澆道切 斷。 第13圖係顯示,使用注入孔44c的直徑2.6mm、錐 角0爲1°、流道連接部44d的直徑3.5mm、長度25mm的 澆道襯套4 4時之數據。在本例,由於流道連接部4 4 d之 直徑爲3.4 7 mm,該部分的冷卻硬化很耗時間。在本例, 當冷卻溫度爲7〇 °C的情形,在成形循環時間5秒時會發 生澆道切斷和牽絲,在冷卻溫度80 °C、90 的情形’在 成形循環時間6秒時也會發生澆道切斷和牽絲。因此’當 . 注入孔的直徑爲2 · 6mm的情形,爲了達成理想成形循環 ^ 時間之6秒以內的情形,其可說是上限的直徑。 第14圖係顯示,使用注入孔44c的直徑分別爲 1.6mm、2.0mm、2.3mm、2.6mm,錐角 0 爲 1.5°、長度 25mm的澆道襯套44時,以冷卻溫度70°C進行測試時之 數據。在本例,流道連接部之直徑,分別對應於前述注入 孔尺寸而形成2.9mm、3.3mm、3.6mm、3.9mm,此最厚的 -21 - (19) (19)200843934 部分之冷卻硬化特別會發生過慢的問題。在注入孔44c的 直徑2 · 6 m m、錐角0爲1 . 5 °的例子’在冷卻溫度7 〇 C的情 形,在成形循環時間5秒時會發生澆道切斷,在6秒時會 發生澆道之伸長或彎曲。又關於其他注入孔44c之直徑尺 寸,相較於澆道襯套44的內孔44a之錐角0爲1°的情 形,若不將最短的成形循環時間予以延長則會發生成形不 良。因此,冷卻最慢的澆道襯套44之流道連接部44d的 直徑3.6mm,乃實用範圍最大的直徑。 因此,即使如第1 3圖所示注入孔44c直徑爲2.6mm 的情形,如第14圖所示,流道連接部4 4 d的直徑上限可 想定爲3.6mm。如第9圖之實線外側的虛線所表示’注入 孔44c之直徑2.6mm(截面積5.31mm2,以下四捨五入)、 流道連接部44d之直徑3.6mm(截面積10.17 mm2,以下四 捨五入)之澆道P1,乃本發明中最大容量之澆道P1。關於 澆道襯套4 4的內孔4 4 a之較佳錐角0 ’從注入孔4 4 c朝 流道連接部44d宜以0.5〜2.0°擴徑。然而’當流道連接 部44d的直徑超過3.6mm時,即使成形循環時間爲6秒 (冷卻時間3.9秒),流道連接部44d附近之冷卻硬化仍過 慢,在開模時可能會發生澆道P 1之切斷。一旦澆道P 1在 澆道襯套44內殘留時,除必須中斷連續成形作業外,熟 練的作業員必須在狹小空間內作業以取出澆道P 1,如此 可能造成模具損傷。在澆道襯套44的小徑部之冷卻媒體 流路51設置部分的壁厚44e宜爲15〜30mm左右。 根據上例,來說明本實施形態之2片的4.40g(容積 -22- (20) (20)200843934 3.7 cm3)的導光板P和澆道P1的重量及容積。關於澆道P1 最小的情形,當使用注入孔的直徑p 1 a爲1 . 6 mm、具有內 孔44a(脫模傾斜角度0相對於中心線各〇·5 °,全長 Plc = 20mm)之湊道襯套44,所成形出之―道Ρ1谷積爲 49.5mm3(以下四捨五入),澆道P1重量g2爲〇.〇6g(以下 四捨五入)。相對於導光板P成形品重量^以4.40^),澆道 P 1之重量g2的重量%爲1 · 4 % (以下四捨五入)(容積比也相 同)。關於澆道P 1之重量及容積最大的情形’當使用注入 孔的直徑Pla爲2.6mm、流道連接部44d之直徑Plb爲 3.6mm、具有內孔44 a(全長Plc = 30 mm)之澆道襯套44,所 成形出之澆道P1容積爲226.3 mm 3(以下四捨五入),澆道 P1重量g2爲0.2 7g(以下四捨五入)。相對於導光板P成 形品重量 gl(4.40g),澆道P1之重量 g2的重量%爲 6.1 % (以下四捨五入)。因此澆道P1相對於導光板P之重 量%,前述1.4〜6.1 %係可滿足冷卻效率及成形品狀態之 範圍。 此外,關於更佳的脫模傾斜角度Θ及澆道P1的全長 (與內孔44a的全長一致)等,當選擇注入孔44c的直徑 Pla爲1.6mm、脫模傾斜角度Θ爲各Γ(相對於第5圖中 一點鏈線所代表的中心線L)、具有全長爲25mm的內孔 44a之澆道襯套44時,所成形出之澆道P1容積爲 81.4mm3(以下四捨五入),澆道P1重量g2爲0.10g(以下 四捨五入)。相對於導光板p成形品重量gl(4.40g),繞道 P1之重量g2的重量%爲2.3%(以下四捨五入)。又當選擇 -23- (21) (21)200843934 注入孔44c的直徑Pla爲2.6mm、脫模傾斜角度0爲各i。 (相對於中心線L)、具有全長爲25mm的內孔44a之澆道 襯套44時,所成形出之澆道P1容積爲i81. 0mm3(以下四 捨五入),澆道P1重量g2爲0.22g(以下四捨五入)。相對 於導光板P成形品重量gl(4.40g),繞道P1之重量g2的 重量%爲5.0 % (以下四捨五入)。因此,當澆道p 1相對於 導光板P之重量%在上述範圍之2.3〜5.0 %時,基於澆道 P 1成爲可脫模狀態前之冷卻速度、熔融樹脂之流動以及 成形性之觀點,此爲更佳範圍。 又在要取出 2個對角尺寸(實際尺寸)5吋、板厚 0.5mm的導光板(容積3 8 76mm3、重量4.65g)的情形,當 選擇注入孔44c的直徑PI a爲2.6mm、脫模傾斜角度0相 對於前述中心線L各爲1 °、具有全長P 1 c爲2 5 m m之內孔 44a之澆道襯套44時,如前述般澆道P1的重量g2爲 0 · 2 2 g,澆道P 1比例爲2 · 4重量%。如此般達成澆道P 1及 流道P2之小型輕量化的效果主要基於,藉由前述般進行 射出模壓及射出壓縮成形,而能採用較慢的射出速度,因 此不須加大澆道P 1的截面積以減少熔融樹脂的流動損 失。此外,在射出模壓及射出壓縮成形時,藉由開閉模及 合模機構來壓縮模穴1 4、1 4內的樹脂以抑制模穴1 4、1 4 內之樹脂的凹陷,因此不須從射出裝置側進行強力的保 壓,先進行澆道P 1之冷卻硬化也可以,結果不須加大澆 道P1之截面積。特別是在進行澆道切斷之形式,在進行 澆道切斷前係透過澆道P1進行保壓,在完成澆道切斷後 24- (22) 200843934 停止保壓,藉此降低澆道p 1的內壓而使澆道P 1稍微 凹陷,如此能更容易地使澆道p 1從澆道襯套44之 44a進行脫模。 在前述澆道襯套44之小徑部的周圍,形成用來 澆道P 1及流道P2之冷卻媒體流路5 1。具體而言, 塊43之與澆道襯套44相對向的部分,以在澆道P1 方向長度爲5〜10mm、在與長方向正交的方向之寬虔 〜6mm的方式,形成凹部狀之冷卻媒體流路5 1。在 襯套44和嵌塊43之間,爲了防止冷卻媒體之洩漏而 有Ο型環5 1 a、5 1 a。在澆道襯套4 4之小徑部,冷卻 流路51設置部分之壁厚44e宜爲20〜30mm。在本實 態,由於澆道P1之全長較短(25mm),故僅在一處設 卻媒體流路5 1,但也能將注入孔側和流道連接部側 予以冷卻。又在本實施形態,雖是使用溫度經控制的 作爲冷卻媒體,但也能使用油。 如第2圖至第4圖所示,從澆道襯套44之流道 部44d朝向模穴形成部,在嵌塊43之與可動模具12 向的面上,形成有流道形成部54。又前述流道形成姜 係形成於,相對於抵接塊46之抵接面46a,呈槽狀 級的位置(固定盤側的位置),藉此構成固定模具13 流道P2形成面。流道形成部54之與熔融樹脂流動方 交的方向上之寬度,係從鄰接於澆道襯套44的部分 模穴14、1 4逐漸變寬。關於流道形成部54,爲了與 模具1 2之流道形成部3 2間維持等間隔,係以凹部對 產生 內孔 冷卻 在嵌 的長 爲 3 澆道 嵌合 媒體 施形 置冷 分別 水來 連接 相對 P 54 低一 側之 向正 朝向 可動 向於 -25- (23) 200843934 凸部、凸部對向於凹部的方式來形成。 流道形成部54之凹部,係以連續的同一面和澆口形 成部連接。因此,流道P2和澆口 P3彼此之形成部並無法 明確地區隔。又連續於模芯部1 6之流道形成部3 2而形成 由澆口切斷構件24的端面所構成之澆口形成部。澆口形 成部之與熔融樹脂的流動方向正交的方向上之寬度(澆口 切斷構件24的寬度)比澆道P1的直徑更寬。因此本實施 形態之澆口 P3,係屬於膜狀澆口之一種,其長度(寬度)爲 導光板的側面(與光入射面相反側之側面)的長度之2/3〜 1 /4左右,且透過前述膜狀澆口連接流道及模穴。 在嵌塊43的流道形成部54和模穴形成塊42的模穴 形成部的主要部形成部42a之間,固設有澆口切斷構件 45。澆口切斷構件45,係由C標度洛式硬度55〜63 (HRC) 的合金工具鋼(SKD鋼)等的硬質金屬構件所構成之長方形 薄板,其硬度比用來形成模穴形成部之主要部形成部4 2 a 的構件更高。澆口切斷構件45之與熔融樹脂的流動方向 正交的方向上之寬度,係和澆口形成部相同或稍寬。澆口 切斷構件45之厚度爲0.4〜0.8mm左右。澆口切斷構件 4 5的前面和模穴形成部1 6 a相對向,而構成模穴形成部 的一部分。澆口切斷構件45之澆口部側的角部,係形成 澆口切斷具45 a(切刀)。當可動模具12之澆口切斷構件 24前進時,澆口部側的面係與其隔著些微間隔相對向的 面。 接著,使用第6圖的流程圖來說明,使用本實施形態 -26- (24) (24)200843934 之成形模具11之成形方法(射出模壓成形方法)。在本實 施形態,係用4.2秒的成形循環時間,成形出平面方向的 對角尺寸4吋、板厚〇.38mm之均一板厚的導光板。其 中,開閉模時間(包含開模時間、取出時間、閉模時間)爲 1.4秒,中間時間(包含減壓時間)0.1秒,射出時間0.05 秒,保壓時間0.45秒,冷卻時間2.2秒(實質上的冷卻是 從開始射出才進行)。因此,在本實施形態,在用來冷卻 可動模具1 2的模穴形成部1 6a之冷卻媒體流路1 7、用來 冷卻突出銷2 3及流道形成部3 2的附近之冷卻媒體流路 3 3、用來冷卻固定模具1 3的模穴形成部之主要部形成部 4 2a之冷卻媒體流路50中,係流過被調溫器控制成80〜 1 20 °C左右(比成形用的樹脂之聚碳酸酯之玻璃轉化溫度 Tg低3 0〜10 0°C )之冷卻媒體(冷卻水)。又送往前述冷卻 媒體流路5 1之冷卻媒體的溫度,較佳爲送往冷卻媒體流 路5 0的冷卻媒體之溫度以下。亦即如第1 1圖所示,送往 澆道襯套44之冷卻媒體流路5 1之冷卻水溫度爲40 °C 時,在7秒以上的成形循環時間下,澆道襯套44會過度 冷卻而發生在成形品中混入冷料塊的問題。又當和固定模 具1 3之模穴形成塊4 2間之溫度差過大時’各部位會發生 熱膨脹差而產生轉印之相關問題,因此不宜在4 0 °C以下 進行成形。又當送往前述冷卻媒體流路5 1的冷卻水溫度 爲120°C時,在4秒下會發生澆道切斷,實際上在該溫度 下,由於可能會發生澆道切斷,因此在此溫度下進行成形 毫無意義。 -27- (25) 200843934 此外,射出裝置之前部區域(最接近噴嘴的區域)的溫 度設定爲3 5 0 °C,並對聚碳酸酯之熔融樹脂進行計量。在 使用聚碳酸酯時前述射出裝置之前部區域的溫度設定,基 於熔融樹脂流動性之觀點,較佳爲將溫度設定爲高溫之 3 20〜3 80 °C。藉由作動合模汽缸10,使組裝於可動盤9 之可動模具1 2抵接在組裝於固定盤6之固定模具1 3,以 進行閉模。這時,一旦模芯部1 6前進至最前進位置,彈 簧1 8收縮使可動盤9等前進至閉模完成位置(〇位置,可 動框部1 9和模具本體部1 5抵接)後,再度藉由合模汽缸 1 〇使可動盤9等進行微量後退,而控制成停止於第2圖 之開始射出時的位置A。藉此,能使可動模具1 2之模芯 部1 6停止於比成形完成位置更靠開模方向的位置。當可 動盤的位置是藉由伺服馬達等來進行更高精度的定位時, 可在最初就使可動盤移動至開始射出時的位置A。 這時可動盤9及可動模具1 2之模芯部6之開始射出 前的位置A係控制成,使固定模具13之模穴形成部42 a 和可動模具1 2之模穴形成部1 6a的距離等於導光板p的 板厚加上〇· 1〜〇.3mm。關於前述位置,相對於導光板p . 之板厚,前述模穴形成部4 2 a和模穴形成部1 6 a之距離較 佳爲120%〜2 00%,在板厚較薄的情形,宜爲前述比例中 之高數値;在板厚較厚的情形,宜爲前述比例中之低數 値。當停止於此開始射出時之位置A時,藉由開閉模及 合模機構之合模汽缸1 〇,來產生不致改變前述位置的程 度之些微的合模力。又使用伺服馬達時,係進行位置控制 -28- (26) (26)200843934 而停止於前述停止位置。 當可動模具1 2停止,而形成連接於流道(包含厚度可 變的澆口)之厚度可變的模穴 14、14時,對前述模穴 14、14內進行空氣吸引。關於空氣吸引,係將未圖示之 真空裝置和空氣通路3 4、5 3間之電磁開閉閥打開,從空 氣通路3 4及與其相連之模芯部1 6和可動框部1 9的間 隙、從空氣通路5 3及與其相連之模穴形成塊42和抵接塊 46的間隙等,來吸引模穴14、14內的空氣。在開始射出 前使模穴1 4、1 4內形成減壓狀態之目的在於,在射出 時,爲了使熔融樹脂在模穴1 4、1 4內不受空氣的阻力而 能迅速地流動至光入射面形成塊20側的端部,此手法在 進行板厚較薄(0.2〜1.0mm)的導光板P之成形時特別有 效。在本實施形態,由於噴嘴2b持續抵接於澆道襯套 44,因此減壓時不致從澆道襯套44側吸引空氣。 接著,在經過既定的中間時間(減壓時間)後,使射出 裝置3之未圖示的射出機構作動,使加熱筒2a內之螺桿 前進而進行熔融樹脂的射出。透過前述噴嘴2b之噴嘴 孔、利用澆道襯套44的內孔44a所形成出之澆道P1、流 道P2以及澆口 P3,來將熔融樹脂朝模穴14內射出。在 本實施形態,射出速度之峰値設定爲200mm/seC,藉由射 出機構之射出用伺服馬達來控制螺桿的前進速度。射出速 度宜爲150〜400mm/sec。當藉由射出壓縮成形來成形出 板厚 0.4〜1 .0mm的導光板時,也能採用相同的射出速 度。前述射出速度 150〜400mm/sec,比起進行相同成形 -29- (27) (27)200843934 之一般射出成形時之500mm/sec以上,其數値較低。由於 在這種較低射出速度下對模穴1 4、1 4內進行射出充塡, 故能減小所成形出之導光板P的澆口附近之內部應力。 在射出成形時,如前述般由於合模力接近0,藉由射 出壓力能使可動模具1 2之模芯部1 6及可動盤9等後退, 而使模穴1 4、1 4的間隔變寬。當射出後(與射出完成大致 同時),在合模裝置5側使開閉模及合模機構之合模汽缸 1 〇作動,使可動盤9及可動模具1 2朝閉模方向移動。藉 此,使模芯部16相對於可動框部1 9前進,由於模穴 14、14之固定模具13的模穴形成部42a和可動模具12 之模穴形成部16a的距離變短,模穴14、14內的熔融樹 脂被壓縮。這時,對合模汽缸1 〇進行壓力控制,檢測油 壓並控制成設定値之400 KN。該數値,換算成模穴 14、 14內之樹脂壓力爲150MPa左右。這時的昇壓速度,係以 〇.〇3秒高速昇壓至設定値。昇壓速度越快越好,較佳爲以 0.02〜0.05秒昇壓。合模速度也是越快越好,將輸出控制 成峰値爲 3 0 0〜6 0 0 m m / s e c。相較於使用伺服馬達的機 構,使用合模汽缸1 〇的機構,在相同規模時之起動較 快,而能達成高速的合模速度。在本實施形態之成形出對 角尺寸4吋的導光板之例,係以300KN進行合模。視情 形,也能在開始射出的同時、或射出中(開始射出後)進行 合模,這時,可能模穴14、14的間隔幾乎或完全不變 寬。此外,也能藉由位置控制,使可動盤從開閉模及合模 機構之作動開始位置移動至開始壓縮之既定位置、或成爲 30- (28) (28)200843934 既定合模力(或檢測樹脂壓)的位置,之後再切換成進行壓 力控制。 當藉由射出裝置使螺桿位置到達既定的保壓切換位置 時,從射出控制切換成壓力控制之保壓控制。又保壓宜爲 5〜20 MPa,以進行幾乎完全沒有緩衝量之射出及保壓。 在本實施形態,當經過既定時間時,藉由未圖示之澆口切 斷構件驅動裝置,使可動模具1 2之各澆口切斷構件24前 進0.45〜0.8 mm,而將澆口 P3、P3切斷。這時,在可動 模具12之澆口切斷構件24的澆口切斷具24a(切刀)和固 定模具13之澆口切斷構件45之澆口切斷具45 a(切刀)之 間分別進行澆口 P3、P3之切斷。在進行澆口切斷時,當 然澆口 P3之熔融樹脂尙未到達完全硬化的狀態。 接著,當藉由澆道切斷構件2 4進行澆口 P 3之切斷 後,澆道切斷構件24保持於前進位置。在本發明,即使 未藉由射出裝置實施保壓,經由開閉模及合模機構(合模 汽缸10)之驅動使可動模具12之模芯部16前進,即可將 模穴1 4、1 4內之熔融樹脂壓縮,因此,即使因冷卻而發 生收縮’仍不致產生凹陷,而能進行良好的轉印成形。然 後模芯部16前進,最後停止於導光板p的板厚b的位 置。另一方面,射出裝置係停止進行保壓,在既定時間後 可開始進行計量。又在澆道P1,由於來自射出裝置3之 保壓停止,可使澆道P i內的壓力下降。接著,藉由冷卻 媒體使澆道P i進行冷卻收縮而發生些微的凹陷,而容易 在其與澆道襯套44之內孔44a之間形成間隙,再配合上 -31 (29) 200843934 對內孔44a實施粗面加工,而使澆道P 1容易進行脫模。 在本實施形態,由於澆道P 1相對於前述中心線L之 脫模傾斜角度Θ各爲1 °,故更容易進行澆道P1之脫模。 當脫模傾斜角度0過小時(各比〇 . 5 °小),無法進行澆道P 1 之脫模;當脫模傾斜角度Θ過大時(各比2°大)時,相對於 注入孔44c附近之澆道P1的冷卻硬化進展,流道部44d 附近之澆道P1的冷卻硬化進展較慢,因此勉強進行澆道 P1的脫模時,澆道P1在流道P2附近發生切斷的可能性 很高。又注入孔44c之直徑Pla爲2.0mm,可防止澆道 P1進行膜模時發生牽絲。當注入孔 44c的直徑超過 3.0 m m時會發生牽絲,但比1.6 m m更小時樹脂之流動損 失變大,因此必須要求比本實施形態的數値更高之射出速 度,如此導光板P發生不良品的可能性變高。 又經過既定時間後,降低合模力,並從可動模具1 2 之可動框部1 9和模芯部1 6之間的空氣通路3 4、固定模 具13之抵接塊46和模穴形成塊42及嵌塊43之間的空氣 通路53等,將脫模用空氣送往模穴14、14及流道P2。 接著作動合模裝置,依序進行排壓、開模。這時,由於和 澆道P1形成一體之流道P2咬合於咬入部23a,當澆道P1 從澆道襯套44脫模時,係和流道P2 —起以保持於可動模 具1 2側的狀態取出。進行澆道切斷後之導光板P、P,也 是以保持於可動模具1 2側的狀態被取出。又在可動模具 1 2停止於開模完成位置之大致同時,使未圖示之取出用 機器人動作,同時使頂出裝置之突出銷2 3前進。本實施 -32- (30) (30)200843934 形態所使用之取出用機器人,能分別進行澆道P 1及流道 P 2的把持、導光板之吸附。在前述取出時,澆口切斷構 件24係在前進位置呈停止狀態。本實施形態之導光板澆 口 P 3,由於不是構成光入射面的部分,即使未進行精加 工處理也能當作導光板使用。澆道P 1及流道P2,雖如上 述般僅佔極小的重量%,但也能另外進行回收再利用。這 時,由於澆道P1直徑小,可用小型的粉碎機施以粉碎, 因此能提高原生材(v i r g i n m a t e r i a 1)的比例。 其次說明導光板之對角尺寸及板厚和成形條件的關 係。導光板的對角尺寸和板厚的關係,雖有些部分和樹脂 或成形條件有關而無法做嚴密的區分,但大致可區分如 下。對角尺寸2〜5吋之導光板,能在板厚0.3〜0.5mm的 範圍進行成形,依其條件也可能成形出〇.2mm以上者。 附帶一提,對角尺寸2吋、板厚0.3mm的導光板成形出2 個的情形,容積爲744mm3,成形品重量gl爲0.89g。對 角尺寸5〜6吋的導光板,基於樹脂流動和冷卻速度的關 係,板厚宜爲0.3〜0.6mm;對角尺寸6〜7吋的導光板, 板厚宜爲 0.4〜0.6mm。例如 7吋的導光板,由於從澆口 至離澆口最遠的角部之距離約1 5 cm,故越大型的導光板 要求更高的射出速度和更高的合模速度。又導光板越大型 時’爲了使樹脂良好地流動,宜提局溶融樹脂的溫度。又 關於合模力,對角尺寸2〜5吋之導光板成形出1個或2 個的情形宜爲2 0 0〜5 0 0 KN,6吋以上的導光板成形出1 個的情形宜爲5 00〜1 000 KN。合模力,係考慮導光板之投 -33- (31) (31)200843934 影面積’以既定合模速度之峰値爲300〜600mm/sec的方 式來決定。 以下說明導光板之成形循環時間。對角尺寸 2〜5 吋、板厚〇·2〜0.5mm的導光板成形出2個的情形,或是 對角尺寸5〜7吋、板厚0.4〜0.6mm的導光板成形出1個 的情形,從閉模完成後經射出而到達開始開模的時間(成 形時間)爲1·75〜4.0秒,從開始開模經取出導光板到達閉 模完成的時間(開閉模時間)爲〇 . 7 5〜2 · 2秒,總成形循環 時間可在6 · 2秒內。第1 5圖係顯示本發明之藉由壓縮成 形以最短2.5秒之循環時間來成形出導光板之流程圖。其 中,開閉模時間(取出時間、中間時間)爲0_ 75秒,射出遲 延時間(增壓時間)爲〇 · 1秒,射出時間爲0 · 0 5秒,保壓時 間爲0 · 4秒,冷卻時間爲1 · 2秒。又在進行本發明之導光 板的成形中,導光板的板厚最高僅爲1.0mm以下,導光 板之平面方向的尺寸則不太會影響成形循環時間。對成形 循環時間影響最大的,乃厚度最厚的澆道P 1 (其中特別是 流道連接部),若進一步縮短成形循環時間,澆道P 1的冷 卻時間不足而造成硬化不足,會發生澆道P 1之切斷。如 第16圖之流程圖所示,對角尺寸3吋、板厚〇. 6mm(均一^ 板厚)、具有轉印圖案之導光板能以成形循環時間6.0秒 之射出壓縮成形來成形出,這時之冷卻時間爲3 · 9秒。所 成形之導光板的面積、板厚越大,成形循環時間有越長的 傾向,但若更加延長成形循環時間,會帶來經濟性方面的 問題,例如超過9〜1 0秒時,還會發生噴嘴冷卻、加熱筒 -34- (32) (32)200843934 內的樹脂劣化等的問題。 本發明如第8圖所示,也能使用另一實施形態之導光 板的成形模具6 1來進行射出壓縮成形或射出模壓成形。 該成形模具61係所謂嵌合式模具。具體而言,在固定模 具66的凹部內嵌入可動模具62的凸部後,在嵌合面 64b、65a和模穴側面形成部7ia間會產生些微的間隙(不 致使熔融樹脂漏出),而在兩模具62、66之間形成模穴 72。固定模具66之澆道襯套69,可採用與第2圖等所示 之實施形態相同者,可變更的範圍也相同。 關於本發明,雖未逐一列舉,但並不限於上述實施形 態,熟習此技藝人士根據本發明的主旨所做的改變,當然 也包含於本發明。在本實施形態,雖是說明對角尺寸4吋 之行動電話用的導光板之成形模具Η,但導光板的形狀 及種類沒有限定。因此,除板厚均一的導光板外,也可以 是板厚從光入射面側往另一側越來越薄之楔形導光板。楔 形導光板’係在光入射面以外的部分形成澆口,而能成形 出薄側部的板厚在上述0.2〜0.6mm範圍內者。關於光之 入射,可適用於從側面入射之側光型導光板、從背面入射 後從前面出射之背光型導光板(包含光擴散板)、將外光予 以反射者。關於反射面和光出射面的形狀,可考慮爲鏡 面、凹點、溝槽、全像圖等各種的組合。本發明也適用於 與光之入射或出射有關之透鏡、薄板等等。總之,本發明 之射出模壓成形及射出壓縮成形,係適用於至少一面爲轉 印面之物。 -35- (33) (33)200843934 在本實施形態所說明之成形模具1 1,係針對在水平 方向進行開閉模之射出成形機,但也能適用於在垂直方向 進行開閉模者。在上述實施形態,係藉由射出成形機之開 閉模及合模機構,來改變固定模具之模穴形成部和可動模 具的模穴形成部間的距離以壓縮熔融樹脂;但也能在可動 盤或可動模具內設置射出模壓用之油壓缸,藉由該油壓缸 使模芯部移動以進行熔融樹脂之壓縮。 成形所使用之樹脂,雖僅記載聚碳酸酯(例如,出光 興產之達夫隆LC 1 5 00),但其他的光學特性及流動性優異 的樹脂也可以,例如:甲基丙烯酸樹脂(比重1.2)、環烯 烴聚合物樹脂(比重1.0)等等。本發明之導光板的範疇, 係包括光擴散板等之具有透光性的樹脂板。 【圖式簡單說明】 第1圖係本實施形態的導光板的成形方法所使用之射 出成形機之前視圖。 第2圖係本實施形態的導光板的成形方法所使用之成 形模具之截面圖,其顯示可動模具停止於開始射出前的位 置的狀態。 第3圖係本實施形態的導光板的成形方法所使用之成 形模具之截面圖,其顯示模穴內的樹脂被壓縮的狀態。 第4圖係本實施形態的導光板的成形方法所使用之成 形模具之截面圖,其顯示澆口被切斷的狀態。 第5圖係第4圖之澆道襯套之主要部分放大圖。 -36- (34) (34)200843934 第6圖係本實施形態的導光板之成形方法之流程圖。 第7圖係本實施形態之導光板之成形方法所製得之澆 道及流道之立體圖。 第8圖係另一實施形態之導光板的成形方法所使用之 成形模具之截面圖。 第9圖係本實施形態之導光板之成形方法所製得之澆 道之放大側視圖。 第1 0圖係顯示另一實施形態之導光板的射出壓縮成 形模具之澆道形狀和成形循環時間的關係。 第1 1圖係顯示另一實施形態之導光板的射出壓縮成 形模具之澆道形狀和成形循環時間的關係。 第1 2圖係顯示另一實施形態之導光板的射出壓縮成 形模具之澆道形狀和成形循環時間的關係。 第1 3圖係顯示另一實施形態之導光板的射出壓縮成 形模具之澆道形狀和成形循環時間的關係。 第1 4圖係顯示另一實施形態之導光板的射出壓縮成 形模具之澆道形狀和成形循環時間的關係。 第1 5圖係顯示另一實施形態的導光板之成形方法之 流程圖。 第1 6圖係顯示另一實施形態的導光板之成形方法之 流程圖。 【主要元件對照表】 1 :射出成形機 -37- (35) (35)200843934 3 :射出裝置 5 :合模裝置 6 :固定盤 9 :可動盤 1 〇 :合模汽缸 1 1、6 1 :成形模具 12、 62 :可動模具 13、 66 :固定模具 14、 72 :模穴 1 5、4 1 :模具本體部 1 6 :模芯部 16a、42a :模穴形成部 1 9 :可動框部 24、45 :澆口切斷構件 44、69 :澆道襯套 44a :內孔 44b :噴嘴接觸面 44c、69a:注入孔 44d :流道連接部 17、33、50、51、6 8b、70a :冷卻媒體流路 P :導光板 P1 :澆道 P 1 a :注入孔的直徑 P 1 b :流道連接部的直徑 -38- (36) 200843934 P 1 c :全長 P2 :流道 P 3 :澆口 -39In the example disclosed in Patent Document 3, when forming a light guide plate having a thickness of 0·6 5 m and a diagonal size of 1 〇·6 ,, it is necessary to use an exit speed of 500 m m / s e c or more. In Patent Document 3, for a one shot weight of 65 g, the molded article weight is 29 g, and the molded article weight ratio is 44. 6%. As can be seen from Fig. 1, Patent Document 3 is a direct gate type having no flow path, so that the runner weight ratio is 50% or more. That is, in order to secure the above-described injection speed, it is necessary to increase the cross-sectional area of the runner, and based on the above description, the weight of the runner portion becomes heavy. Incidentally, in Patent Document 2 and Patent Document 3, the molding cycle time and the like are not mentioned at all, but in the case of the above-described runner, it is judged by the common sense that the molding cycle time of 20 seconds or more is required. In Patent Document 4, a light guide plate or the like is formed by using an injection molding die having a sprue bushing (having an effective diameter of 1 to 10 mm in a portion where the injection molding nozzle is in contact with the sprue). In the first embodiment of Patent Document 4, the plate thickness is set with a cycle time of 40 seconds. 0~ 6. Forming of a 0 mm wedge-shaped light guide plate. However, in Patent Document 4, injection molding is used (the cavity volume at the time of mold clamping is constant), and it is necessary to mold the resin into a cavity having substantially the same thickness as the thickness of the light guide plate. A light guide plate with a thick plate, but for a light guide plate having a thin plate thickness, it is difficult to form a good product with a low injection speed. Further, regarding the effective diameter of the contact portion between the runner bush and the nozzle, when the effective diameter is 3 mm or less, the thickness of the plate is formed to be 0. A thin light guide plate of 6 mm or less may have difficulty. That is, when the effective diameter of the sprue bushing is 3 mm or less, even if a high-speed injection of 500 mm/Sec or more is performed, it is difficult to charge the end of the light guide 200843934 (4) plate (thin plate thickness). When the injection speed is higher, the residual stress causes deformation of the light guide plate, and there is a problem that uneven brightness distribution occurs. Therefore, in Patent Document 4, it is difficult to apply the portion having a small inner diameter of the runner, and as disclosed in Fig. 6, it can be applied only to the contact portion of the sprue and the injection molding nozzle having an effective diameter of about 4.2 mm. Further, in Patent Document 4, the temperature regulating pipe dedicated to the cooling runner is not disclosed, and should be used together with other parts for cooling, so that the molded article and the runner cannot be cooled at an appropriate temperature, respectively. Further, in Patent Document 4, a sprue bushing of a material having a thermal conductivity of 35 W/m·K or more is used to promote cooling, and when the effective diameter of the sprue bushing is 3 mm or less, the sprue is partially sprinkled. The cooling hardening may not be sufficient to maintain the pressure from the injection device, and the formed light guide plate may be recessed. Furthermore, since the sprue bushing has a high thermal conductivity, when the nozzle is continuously contacted with the sprue bushing for forming, the heat at the tip end of the nozzle is excessively lost, so that it is required to retreat the nozzle every time the forming is performed, so that the forming cycle time cannot be shortened. . [Patent Document 1] Japanese Laid-Open Patent Publication No. 2003-145455 (paragraph [0016], first drawing) [Patent Document 2] Japanese Laid-Open Patent Publication No. 2004-9055 No. 5 (Application No. 1, No. 2, No. 2) [Patent Document 3] Japanese Laid-Open Patent Publication No. 2006-341512 (paragraph [0026], Fig. 7) [Patent Document 4] Japanese Laid-Open Patent Publication No. 2007-83462 (Patent Application No. 1, paragraph [001 6] (6th) 200843934 (5) SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object thereof is to provide a molding die and a forming method for a light guide plate, which solve the problems of the prior art, that is, conventional injection molding In order to form the light guide plate, in order to expel the resin at a high speed into a thin mold cavity having substantially the same thickness as the thickness of the light guide plate, the diameter of the runner must be increased to minimize the flow loss of the molten resin, and must be The mold cavity and the runner are kept under pressure, and as a result, the problem that the runner completely cools and hardens takes too long. At the same time, a forming mold and a forming method for a light guide plate are provided, and even a light guide plate forming mold of a cold runner type which is simple in mold structure and easy to adjust at the start of forming can reduce a portion other than the light guide plate, that is, a flow path, The proportion of the portion of the runner that causes the loss of the formation, and the productivity can be improved. Further, there is provided a molding die and a molding method for a light guide plate capable of reliably releasing a runner even if the cooling time of the runner is shortened. A molding die for a light guide plate according to the first aspect of the invention is a molding die for a light guide plate that is formed in a cavity forming portion formed between a fixed mold and a movable mold, and is characterized in that: The hole forming portion can be compression-molded to form a molded product having a volume of 7. a light guide plate of 8 cm 3 or less; a sprue bushing connected to the cavity forming portion via a flow path forming portion, the injection hole having a diameter of 1 · 6 to 2 · 6 mm, and the diameter of the flow path connecting portion being 3 · 6 mm or less And an inner hole having a release angle to the center line; a cooling medium flow path disposed around the sprue bushing and the cooling medium flow path for cooling the cavity forming portion are formed separately. The forming mold and the forming method of the light guide plate of the present invention are formed in a forming mold of a light guide plate of a light guide plate formed in a cavity forming portion formed between a fixed mold and a movable mold. The sprue bushing is connected to the cavity forming portion via a flow path forming portion, and the diameter of the injection hole is 1. 6 to 2. 6mm, the diameter of the runner connection is 3. 6mm or less, and having an inner hole having a demolding angle to the center line; a cooling medium flow path disposed around the sprue bushing and separately forming a cooling medium flow path for cooling the cavity forming portion . Since the molding die is used for compression molding, the molded article has a volume of 7. When the light guide plate of 8 cm3 or less is thinned, the molten resin can be compressed in accordance with the cooling shrinkage of the molten resin in the cavity, and the cooling time and the molding cycle time can be shortened. Further, it is possible to reduce the proportion of the portion other than the light guide plate, that is, the portion where the flow loss is caused by the flow path, the runner, and the like, and the productivity can be improved. [Embodiment] The molding die and the injection molding machine of the light guide plate of the present embodiment will be described with reference to Figs. 1 to 7 . Fig. 1 is a front view of the injection molding machine of the light guide plate of the embodiment. Fig. 2 is a cross-sectional view showing a molding die of the light guide plate of the embodiment, showing a state in which the movable mold is stopped at a position before the start of ejection. Fig. 3 is a cross-sectional view showing a molding die of the light guide plate of the embodiment, showing a state in which the resin in the cavity is compressed. Fig. 4 is a cross-sectional view showing a molding die of the light guide plate of the embodiment, showing a state in which the gate is cut. Figure 5 is an enlarged view of the main part of the sprue bushing of Figure 4. Fig. 6 is a flow chart showing a method of forming a light guide plate of the embodiment. Fig. 7 is a perspective view showing a runner and a flow path obtained by the method for forming a light guide plate of the embodiment. Fig. 9 is a view showing a method of forming a light guide plate of the present embodiment. -9- 200843934 (7) An enlarged side view of the runner produced. The injection molding machine 1 of the present embodiment is a molding machine that performs injection molding and injection molding using a cavity in which the volume can be changed after injection. In the injection molding machine 1, an injection device 3 including a heating cylinder 2a (with a screw) and a nozzle 2b is disposed on a machine tool 4. In this embodiment, the nozzle hole diameter of the nozzle 2b is 1. 5mm. The injection device 3 is controlled by a servo motor for measurement of a measuring mechanism (not shown) and a servo motor for injection of the injection mechanism to control the injection speed, the pressure-holding switching position, the pressure at the time of pressure retention, the amount of injection, and the like. The clamping device 5' is provided with four tie bars 8 between the fixed disk 6 (fixed to the machine tool 4) and the pressure plate 7 (disposed to the machine tool 4), and the movable disk 9 is movably inserted through the aforementioned Tie 8. A clamping cylinder 1 (opening and closing mold and a clamping mechanism) for opening and closing the mold and clamping is disposed on the pressure receiving plate 7, and the punch 10a of the clamping cylinder 10 is fixed to the back surface of the movable disk 9. . The mold clamping speed and the mold clamping force are controlled by the mold clamping cylinder 1 (opening and closing mold and mold clamping mechanism). The opening and closing mold and the mold clamping mechanism of the present embodiment are exemplified by the clamping cylinder 1 控制 controlled by the servo valve. However, a toggle mechanism that is actuated by a servo motor, a ball bearing mechanism, or the like may be employed. The forming mold 1 of the light guide plate is formed by injection molding to form two light guide plates for mobile phones having a uniform thickness (the diagonal dimension in the plane direction is 4 吋 (effective area 3. 5吋), plate thickness 0. 38mm)). Hereinafter, the "light guide for mobile phones" will be simply referred to as "light guide plate". Injection molding is performed to stop the movable mold 12 at a position A where a certain amount of mold opening is ensured before starting the injection (the distance between the cavity forming portion 42a of the fixed mold 13 and the cavity forming portion 1 6 a of the movable mold 12 = The thickness of the light guide plate P is increased by the amount of the light guide plate P, and the molten resin in the cavity 14 is compressed and molded after the start of the injection, and after the start of the injection or after the injection is completed. The injection molding is carried out, and after the completion of the molding, the cavity 14 is ejected only slightly opened, so that the flow loss is less than that of the general injection molding. Therefore, an injection device having a high-speed injection capability is not required, and the molten resin can be ejected at a lower speed and a lower pressure. Further, since the injection speed is slow, the residual stress near the gate P3 can be minimized to form the light guide plate P having a thin plate thickness. As a result, a light guide plate having little bending and excellent brightness balance can be formed. Further, it is possible to solve the problems of silver streaks and black spots which are liable to occur during high-speed injection molding, and the use of a smaller cross-sectional area for the ramps and runners has the advantage of shortening the cooling time. At the same time as the start of the injection or the start of the injection, the movable mold 12 is moved in the mold clamping direction to compress the molten resin, and the flow rate of the molten resin can be accelerated at a position far from the gate portion of the cavity 14 to avoid charging. The flaw is insufficient, and the transfer of the fine pattern can be performed favorably. Further, after the gate P 3 is cut, the normal injection molding die cannot hold the pressure from the injection device. However, in the case of injection molding, the molten resin in the cavity 14 is compressed to correspond to the cooling hardening. The resulting contraction. Further, the mold used for the press molding can be applied to the injection compression molding (the mold 14 is slightly opened by the injection with respect to the mold clamping completion position), and the object of the present invention includes both. Fig. 2 to Fig. 4 are cross-sectional views of the molding die 1 1 of the present embodiment. The forming mold 1 1 is composed of a movable mold 1 2 of a first mold and a fixed mold 13 of a second mold, and two volumes and thicknesses can be changed between the two molds 12 and 13 after the mold clamping. Cavity 1 4. In the present embodiment, it is shown that two molding dies 1 can be taken out. However, when only one -11 - 200843934 (9) can be taken out, the shape of the runner P 1 can be performed by the same molding die. Forming. The movable mold 12 attached to the movable platen 9 of the injection molding machine 1 is provided with a mold main body portion 15, a core portion 16, a movable frame portion 19, and the like. The core portion 16 is fixed to the substantially center of the surface of the mold main body portion 15 on the side of the fixed mold. The surface of the core portion 16 facing the fixed mold 13 is formed into a mirror surface, and constitutes a cavity forming portion 16a for forming a light exit surface, which substantially conforms to the shape of the light guide plate P to form a projection portion or the like. Roughly square. Inside the core portion 16, a plurality of cooling medium flow paths i 7 which are parallel to the cavity forming portion 16a are formed. The portion of the core portion that forms the cavity forming portion and other portions may be formed by separate blocks. Further, although the cavity forming portion 16a is an example of displaying a mirror surface, it is also possible to apply pattern processing such as pits, grooves, holograms, rough surface processing, etc., and it is not excluded that the pressure is applied. Model. A concave portion is formed on the lower surface of the mold main body portion 15 on the side of the fixed mold side, and the spring 18 is attached to the fixed mold side in the concave portion. The fixed mold side of the spring 18 is abutted against the movable frame portion 19 (to be disposed so as to surround the periphery of the core portion 16). In other words, the core portion 16 is disposed in the hollow portion formed by the movable frame portion 19. The entire movable frame portion 19 is movable in the opening and closing mold direction with respect to the mold main body portion 15 and the core portion 19 by the springs 18. The surface of the movable frame portion 19 facing the fixed mold 13 constitutes an abutting surface 19a. On the side opposite to the gate of the movable frame portion 19, a light incident surface forming block 20 for forming a light incident surface is disposed detachably. The front inner portion of the movable frame portion 19 including the light incident surface forming block 20 is formed together with the cavity forming portion 1 6 a -12- 200843934 do) to form a cavity forming portion (for forming the cavity 14). Fig. 2 shows a state in which the movable mold 12 is stopped at the position before the start of ejection. Fig. 3 shows a state in which the molten resin (not shown) in the cavity 14 and 14 is compressed after the injection is started. Fig. 4 shows the state in which the gate is cut after further compression. In the second to fourth figures, the shape of the runner P1, the positional relationship between the core portion 16 and the movable frame portion 19, the contraction of the spring, and the like are exaggerated as compared with the actual case. The heat insulating plate 2 is attached to the side of the movable disk 9 of the mold main body portion 15. The inner space and the hole are provided with projecting pins 23 which can be moved back and forth by the ejector piece of the ejector. The protruding pin 23 is disposed in a hole penetrating through the inside of the mold main body portion 15 and the core portion 16 and has a front end facing the flow path forming portion 32, in order to easily hold the runner P1 and the flow path P2. A biting portion 23a having a zigzag cross section is provided. In order to drive the projecting pin 23, an ejector driving device is disposed in the movable platen 9 or on the side of the punching cylinder 1a of the clamping cylinder 1 of the movable disk 9. Gate cut members 24 and 24 are disposed inside the mold main body portion 15. Each of the gate cutting members 24 is formed of a rectangular thin plate. The front surface thereof constitutes a gate forming portion, and the corner portion of the gate forming portion on the cavity side constitutes a gate for cutting the molten state. The cutting tool 24a. As shown in Fig. 4, one of the side portions of the side of the cavity cutting member 24 on the cavity side constitutes a cavity forming portion after the gate is cut. The size of the gate cutting member 24 is 12 mm in the direction orthogonal to the flow direction of the molten resin (gate width). In order to form the light guide plate P of the present embodiment, the width is preferably 1 Torr to 20 mm. The thickness of the molten resin in the flow direction is preferably -13 - (11) 200843934. 2~2 · 0mm or so. In order to drive the gate cutting member 24, a gate cutter driving device is disposed in the movable platen 9 or on the side of the punching column 1a of the movable disk 9. The gate is cut off with a drive unit that can be operated by a servo-operated hydraulic cylinder or a servo motor and ball screw mechanism. When the hydraulic cylinder controlled by the servo valve is used, the speed control or the pressure control is used to perform the closed loop control when the gate cutting member 24 is advanced. The gate cutting member 24 can be retracted by the spring 25. In the core portion 16, a flow path forming portion 32 is formed on a surface facing the sprue bushing 44 and the insert 43 of the fixed mold 13 to be described later. In the flow path forming portion 32, a convex portion is formed in a portion adjacent to the protruding pin 23 side of the gate cutting member 24, and a concave portion is formed in a portion facing the sprue bushing 44 and facing the protruding pin 23. The gate forming portion of the gate cutting member 24 is located at a position lower than the convex portion (on the movable disk 9 side) except when it is protruded. The reason for this is that, at the time of injection, the resin hardened at the tip end of the nozzle of the injection device is accommodated by a cold slug-like recess to prevent the flow into the cavities 14, 14 and prevent the injection pressure from being excessively applied to the pouring. A burr or the like occurs on the front surface of the mouth cutting member 24. The flow path forming portion 32 is formed by the runner P1 and the flow path P2 of Fig. 7 (separated from the gates P and P by the gate), and it is understood that the connection portion P2a of the runner P1 is connected to the gate P3. The cut portions P2b and P2b are formed to have a larger width, and the width of the joint portion P2a with the runner P1 (substantially equal to the diameter of the protruding pin 23) is about 7 mm, and the cut portion P2b of the gate P3 is The aforementioned 12 mm, that is, the width is 5 mm. Further, the width of the connecting portion P2a with the runner P1 is preferably about 3 to 9 mm. Regarding the plate thickness 2c of the flow path P2, -14- (12) 200843934 is based on the viewpoint of shortening the cooling time while ensuring fluidity', preferably 0. 6 to 1 . About 5mm. In the present embodiment, the flow path forming portion 32 is formed as a part of the core portion 16, and the cross-sectional area of the flow path P2 and the gate P3 can be changed after the emission, but it can also be designed as a flow path forming portion. A part of the movable frame portion, and the cross-sectional area of the flow path and the gate cannot be changed. Further, the flow path and the wrap may be linearly connected to the cavity, and the width and length of the flow path may be appropriately selected, but a film gate is preferably used. Around the protruding pin 23, a cooling medium flow path 33 is formed in the vicinity of the gate cutting member 24 to promote cooling of the flow path P2. The air passage 34 that is blown during demolding is formed between the core portion 16 and the movable frame portion 19. An air passage can also be provided between the gate cutting member 24 and the bore. When the runner is controlled by holding the runner in a state in which the light guide plate and the runner are integrally held, the gate cutting member is not required, and therefore the gate cutting member is not an essential member in the present invention. Next, the fixed mold 13 will be described. As shown in Figs. 2 to 4, the mold main body portion 41, the cavity forming block 42, and the mold are formed on the fixed mold 13 attached to the fixed disk 6 of the injection molding machine 1. Block 43, sprue bushing.  44. Gate cutting members 45, 45, abutment block 46, and the like. On the side of the fixed disk of the mold main body portion 4, a heat insulating plate 47 is attached, and a hole 48 into which the nozzle 2b of the injection device 3 is inserted is formed, and a positioning ring 49 is attached around the hole 48b. A cavity forming block 42 is attached to the movable mold side of the mold main body 邰4, and a surface of the cavity forming block 42 opposed to the movable mold 12 constitutes a main portion forming portion 42a in the cavity forming portion. In the main portion forming portion 42a of the present embodiment, a portion on which a reflecting surface is formed is provided with fine pits. -15- (13) (13) 200843934 Further, inside the cavity forming block 42, a plurality of cooling medium streams g 50 are formed in parallel with the 迮g portion forming portion of the cavity forming portion. Further, between the cavity forming block 42 and the insert 43 and the abutting block 46, an air passage 53 for blowing air at the time of demolding is formed. A cavity forming block 42 and a block 43 are disposed in the mold main body portion 4 1. As shown in Fig. 5 (enlargement of the portion of the chain line of the second point of Fig. 4), a sprue bushing 44 is disposed in the hole in the center of the insert block 43. The sprue bushing 44 is formed with a small diameter portion on the side of the movable mold 12 and a large diameter portion on the side of the nozzle contact surface 44b, and is provided on the center shaft for forming the sprue p &amp; Hole 44a. The sprue bushing 44 is made of stainless steel (Massan loose iron SUS420J2) or steel of comparable hardness. The thermal conductivity of SUS420J2 is 24. At 9 W/m ° C, when the sprue bushing 44 is made of a material having a too high thermal conductivity, the tip end of the nozzle is excessively cooled to hinder the ejection, and the cooling hardening of the molten resin in the sprue bushing 44 progresses too fast. Therefore, although it is not necessary, the thermal conductivity of various stainless steels is preferably in the range of 13 to 30 W/m °C. The Young's modulus of stainless steel is preferably 180 to 210 kN/mm2. When the Young's modulus is too low, problems may occur in a state in which the nozzle contact force is continuously maintained. The inner hole 44a of the sprue bushing 44 is tapered upward from the injection hole 44c facing the nozzle contact surface 44b toward the flow path connecting portion 44d. The angle Θ of the mold release inclination (the inclination required to demold the runner is referred to as the mold release inclination) in the present embodiment is 1° with respect to the center line L as shown in the cross section of Fig. 5, and the both sides are 2°. The aforementioned angles should be 〇. 5~2. 0° (1 to 4° on both sides), more preferably 0. 8~1. 4° (the optimum diameter of the flow path connecting portion 44d can be obtained), particularly preferably 1 °. When the draft angle 0 is less than 0. 5. At the time, the friction with the inner hole -16-(14)(14)200843934 is excessively large, and when the sprue P1 is released, the runner P1 may be cut or the wire is likely to occur. Further, when the draft angle of inclination 0 is greater than 2 · 0 °, the diameter in the vicinity of the flow path connecting portion becomes excessively large, and when the casting of the runner P 1 is performed, the cooling in the vicinity of the flow path connecting portion is slowed down, and the flow path is formed. A problem occurs in the vicinity of the connecting portion where the runner P 1 is cut. Even in the case where the draft angle of inclination 0 is in the vicinity of 2 or 2, when the diameter Plb of the flow path connecting portion 44d of the runner P1 exceeds a certain value or more, the problem of excessive cooling time may occur. The diameter P1 of the injection hole 44c of the inner hole 44a of the sprue bushing 44 of the present embodiment is 2. 0mm (cross-sectional area 3. 14mm2, rounded down below; the diameter Plb of the runner connection 44d is about 2. 87mm (cross-sectional area 6. 47mm2, rounded off below). The diameter P1 of the injection hole 44c is smaller than the diameter of the nozzle hole of the nozzle 2b (this embodiment is 1. 5mm) is bigger. When the diameter P 1 a of the injection hole 44c is too small, the flow loss of the molten resin may be caused or a problem occurs due to excessive cooling of the runner; when it is too large, the molding cycle time becomes long, which may cause the runner to be cut or pulled. . The inner hole 44a of the sprue bushing 44 of the present embodiment has a substantially circular cross-sectional shape, but does not exclude a shape other than a perfect circular shape. Therefore, the diameters P 1 a and P 1 b represent effective diameters. For example, at least one of the injection hole and the flow path connecting portion is a non-circular shape (may be an ellipse, a polygon, a combination of an arc and a straight line, a shape in which different arcs are combined, etc.), as long as it meets the ninth aspect. The injection hole 44c of the largest and smallest sprue bushing 44 shown in the figure may be within the cross-sectional area of the flow path connecting portion 44d. The total length Pic of the inner hole 44a of the sprue bushing 44 is preferably 25 mm. When the total length Pic of the inner hole 44a of the sprue bushing 44 is short, the base -17-(15)(15)200843934 is advantageous from the viewpoint of preventing the flow loss of the molten resin, but in order to provide a cooling medium in the fixed mold 13. In the flow path 50 or the like, the insert 43 must have a thickness sufficient to withstand the nozzle contact pressure, and therefore the length must be 20 mm or more. Further, the total length Pic of the inner hole 44a of the sprue bushing 44 must be 30 mm or less in order to reduce the flow loss of the molten resin. The surface of the inner hole 44a of the sprue bushing 44 is subjected to rough surface processing by sand blasting to facilitate demolding of the runner bushing 44. Therefore, in the present embodiment, in Fig. 5, the space of the runner P1 formed in the inner hole 44a is separated by the one-dot chain line and the flow path P2, and is 1 regardless of the micro-depression and the rough surface portion. 16·6mm3 (rounded below), multiplied by the specific gravity of the polycarbonate used in forming. 2, the result sprue P1 weight g2 is 0. 1 4g (rounded below). In addition, the runner P1 shown in Fig. 7 plus the weight of the flow passage P2 (the average 値 of the measured 値) is 〇. The volume obtained by dividing 5〇g' by the specific gravity is about 416·7mm3 (the following is rounded off). Therefore, the weights of the flow paths P2 and P2 of the present embodiment are 〇 on both sides. 36g (calculated 値)' has a volume of 300. 0mm3 (calculation 値). Diagonal size 3吋, plate thickness 0. The weight of the 3 mm (uniform * plate thickness) light guide plate P molded product is § 1 (the average 値 of the measured 値) is 2. 20g, its volume is about 1 8 3 3. 3 mm3 (rounded below). In the present embodiment, the weight g1 of the molded article of the two light guide plates "two light guide plates" is simultaneously formed. The volume of 4〇g’ is 3666. 6mm3 (volume 3. 7cm3, rounded down below). Therefore, the weight % (calculation formula g2/gl) of the runner P1 weight g2 formed by the sprue bushing 44 is 3.2% (the following is rounded off) with respect to the molded article weight gl of the light guide plate P. In this case, the weight % of the runner P1 to the light guide plate p is formed by the conventional injection molding (the volume of the cavity is fixed) to form the light guide P of the -18-(16) (16) 200843934 light guide plate P, only 1 From /3 to 1/6, the miniaturization of the runner P1 and the reduction in volume can be achieved. The solid line in Fig. 9 is an enlarged cross-sectional view showing a runner obtained by the method for molding a light guide plate of the present embodiment. The broken line in Fig. 9 shows the minimum and maximum cases of the bypass P 1 produced by the present invention. The dot line of Fig. 9 shows a runner obtained by a conventional method of forming a light guide plate, and it can be seen that the volume of the runner P1 of the present invention is very small. It has also been confirmed that the sprue bushing 44 of the present invention can be applied to: diagonal size (actual size) 5 吋, plate thickness 0. 5mm light guide plate (volume 3 8 76mm3, weight 4. 65g) 2 cases are formed ((volume 77 5 2mm3 (7. 8 cm3 (the third decimal place is rounded off), weight 9. 3 g); diagonal size (actual size) 7 吋, plate thickness 0. 5mm light guide plate (volume 7526mm3 (7. 5cm3 (the third decimal place is rounded off), and the weight is 9. 03g) The case where one is formed. As described above, the most influential factor determining the cooling time in the molding cycle time of the present invention is the diameter and the taper angle (release angle) of the runner P1 as shown in Fig. 5 (9. Injection device) The diameter of the nozzle hole (not shown) of the nozzle is 1 · 5 mm. In order to remove the resin at the tip end of the nozzle well, the injection hole 44c on the nozzle hole side of the sprue bushing 44 is used for the mold release. The diameter must be larger than the diameter of the nozzle hole, and should form 1. Injection hole of 6mm or more. Figures 10 to 14 show the use of a small light guide that can be removed (diagonal size 2. 8吋, plate thickness 0. 4mm, volume 0. 94 cm3) Two injection compression molding devices (the structure of the sprue bushing 44 is the same as that of Fig. 5), and the test conditions are as follows: the cooling water temperatures of the cooling medium flow paths for cooling the cavity forming faces are each 90 °C, Nozzle-19- (17) (17)200843934 Temperature 3 25 °C, the front temperature of the heating cylinder is 3 5 5 °C, the temperature of the middle of the heating cylinder is 3 70 °C, and the temperature of the rear of the heating cylinder is 3 60 °C. The injection speed is 300 mm/sec. The first diagram shows that the diameter of the injection hole 44c is 1. 6mm (section product 2. 01mm2, the following rounding), the cone angle 0 shown in Fig. 5 is 1 °, and the diameter of the flow path connecting portion 44d is 2. Data for the runner bushing of 5 mm and 25 mm in length. The runner P1 formed is the one shown by the dotted line on the innermost side of Fig. 9. In this example, when the cooling temperature of the sprue bushing 44 is 70 ° C or 80 ° C, the injection hole 44c of the sprue bushing 44 and the nozzle hole of the nozzle are formed when the forming cycle time becomes longer (5 seconds or more). Excessive cooling causes a problem that the next shot cannot be performed, and a cold slug is mixed into the molded article. When the cooling temperature of the sprue bushing 44 is 90 ° C or more, a defect may occur even when it is 6 seconds or more. Therefore, the diameter of the injection hole 44c of the sprue bushing 44 is 1. At 6mm, the practical range becomes extremely narrow, and when the number is small, it is impossible to make a practical adjustment. Figure 11 shows the diameter of the injection hole 44c. 0 mm, the cone angle 0 is 1 °, and the diameter of the flow path connecting portion 44d is 2. Data for a runner bush 44 of 9 mm and a length of 25 rnm. The runner P1 formed is the one shown in the solid line in Fig. 9. In this example, in the case of each cooling temperature, when the molding cycle time is 2 seconds, the cooling of the runner P1 may not be followed, and the cut-off may occur, but the other results are good. However, when the forming cycle time exceeds a certain level, the economy is not good. Further, when the molding cycle time is excessively extended, the nozzle is cooled to deteriorate the fluidity of the molten resin, and the residence time of the molten resin in the heating cylinder is too long to cause deterioration of the resin (yellowing, black spots). Regarding the temperature of the cooling water, in the case of 4〇 〇c -20-200843934 (18), since the cold block is mixed in the molded product, the cooling temperature for forming is preferably 50 °C or higher. Also at 1 2 0. In the case of (:, the runner is cut off at 4 seconds, so the cooling temperature for forming is preferably 110 ° C or less (especially below the cooling temperature of the cavity forming surface). Fig. 12 shows that The diameter of the injection hole 44c is 2. 3 mm, the cone angle 0 is 1°, and the diameter of the flow path connecting portion 44d is 3. Data for a runner bush 44 of 2 mm and a length of 25 mm. In this case, when the cooling temperature is 70 °C, sprue cutting occurs at a molding cycle time of 3 seconds, at a cooling temperature of 80 ° C, 90 ° C, at a molding cycle time of 5 seconds. A sprue cut will occur. Figure 13 shows the diameter of the injection hole 44c. 6 mm, the cone angle 0 is 1°, and the diameter of the flow path connecting portion 44d is 3. Data for a runner bushing of 4 mm and a length of 25 mm. In this example, the diameter of the flow path connecting portion 4 4 d is 3. 4 7 mm, this part of the cooling hardening is time consuming. In this case, when the cooling temperature is 7 〇 ° C, sprue cutting and drawing are performed at the molding cycle time of 5 seconds, at the cooling temperature of 80 ° C, 90 ' at the molding cycle time of 6 seconds Sprue cutting and wire drawing can also occur. So 'when.  In the case where the diameter of the injection hole is 2 · 6 mm, it can be said that it is the upper limit diameter in order to achieve the ideal molding cycle ^ within 6 seconds. Figure 14 shows that the diameter of the injection hole 44c is 1. 6mm, 2. 0mm, 2. 3mm, 2. 6mm, cone angle 0 is 1. When the sprue bushing 44 of 5° and 25 mm in length was used, the data was tested at a cooling temperature of 70 °C. In this example, the diameter of the flow path connecting portion is respectively formed corresponding to the size of the injection hole. 9mm, 3. 3mm, 3. 6mm, 3. 9mm, the thickest -21 - (19) (19)200843934 Part of the cooling hardening is particularly slow. The diameter of the injection hole 44c is 2 · 6 m m and the taper angle 0 is 1.  In the case of 5 °, in the case of a cooling temperature of 7 〇 C, the runner is cut off at a molding cycle time of 5 seconds, and the runner is elongated or bent at 6 seconds. Further, regarding the diameter of the other injection hole 44c, the taper angle 0 of the inner hole 44a of the sprue bushing 44 is 1°, and the formation may be poor if the shortest molding cycle time is not extended. Therefore, the diameter of the flow path connecting portion 44d of the runner bushing 44 which is the slowest is cooled by 3. 6mm, the largest diameter in the practical range. Therefore, even if the injection hole 44c has a diameter of 2. as shown in Fig. In the case of 6 mm, as shown in Fig. 14, the upper limit of the diameter of the flow path connecting portion 4 4 d can be set to be 3. 6mm. The dotted line on the outer side of the solid line in Fig. 9 indicates the diameter of the injection hole 44c. 6mm (cross-sectional area 5. 31mm2, rounded below), the diameter of the runner connection portion 44d is 3. 6mm (cross-sectional area 10. The runner P1 of 17 mm2, which is rounded down, is the maximum capacity runner P1 of the present invention. Preferably, the preferred taper angle 0' of the inner hole 4 4 a of the sprue bushing 4 4 is from 0 to the flow path connecting portion 44d from the injection hole 4 4 c. 5~2. 0° expansion. However, when the diameter of the flow path connecting portion 44d exceeds 3. At 6mm, even if the forming cycle time is 6 seconds (cooling time 3. At 9 seconds), the cooling hardening in the vicinity of the flow path connecting portion 44d is still too slow, and the cutting of the runner P1 may occur at the time of mold opening. Once the runner P1 remains in the sprue bushing 44, in addition to having to interrupt the continuous forming operation, the skilled worker must work in a small space to take out the sprue P1, which may cause mold damage. The wall thickness 44e of the portion where the cooling medium flow path 51 is provided in the small-diameter portion of the sprue bushing 44 is preferably about 15 to 30 mm. According to the above example, the two pieces of the present embodiment will be described. 40g (volume -22- (20) (20) 200843934 3. 7 cm3) of the weight and volume of the light guide plate P and the runner P1. Regarding the case where the runner P1 is the smallest, the diameter p 1 a of the injection hole is 1 when it is used.  The 6 mm, culvert bushing 44 having an inner bore 44a (with a stripping angle of 0 relative to the centerline of each 〇·5 ° and a full length Plc = 20 mm) has a volume of 49. 5mm3 (rounded below), the sprue P1 weight g2 is 〇. 〇 6g (rounded below). The weight of the molded article relative to the light guide plate P is 4. 40^), the weight % of the weight g2 of the runner P 1 is 1 · 4 % (the following is rounded off) (the volume ratio is also the same). Regarding the case where the weight and volume of the runner P 1 are the largest, 'the diameter Pla of the injection hole is 2. 6 mm, the diameter Plb of the flow path connecting portion 44d is 3. 6 mm, sprue bushing 44 having an inner hole 44 a (full length Plc = 30 mm), the volume of the runner P1 formed is 226. 3 mm 3 (rounded below), sprue P1 weight g2 is 0. 2 7g (rounded below). Compared with the light guide plate P, the weight of the product is gl (4. 40g), the weight of the runner P1, the weight % of g2 is 6. 1% (rounded below). Therefore, the weight of the runner P1 relative to the light guide plate P is as described above. 4~6. 1% is sufficient for the cooling efficiency and the state of the molded article. Further, regarding the better draft angle of inclination Θ and the entire length of the runner P1 (corresponding to the entire length of the inner hole 44a), etc., when the diameter Pla of the injection hole 44c is selected, it is 1. 6mm, the draft angle Θ is the Γ (with respect to the center line L represented by the one-point chain line in Fig. 5), and the sprue bushing 44 having the inner hole 44a having a total length of 25 mm is formed. The volume of P1 is 81. 4mm3 (rounded below), the sprue P1 weight g2 is 0. 10g (rounded below). Relative to the light guide plate p molded product weight gl (4. 40g), the weight % of the weight g2 of the bypass P1 is 2. 3% (rounded below). Also select -23- (21) (21) 200843934 The diameter of the injection hole 44c Pla is 2. 6 mm, the draft angle of inclination 0 is each i. When the sprue bushing 44 of the inner hole 44a having a total length of 25 mm is formed (relative to the center line L), the volume of the sprue P1 formed is i81.  0mm3 (following rounding), the sprue P1 weight g2 is 0. 22g (rounded below). Relative to the light guide plate P molded product weight gl (4. 40g), the weight % of the weight g2 of the bypass P1 is 5. 0 % (rounded below). Therefore, when the weight % of the runner p 1 with respect to the light guide plate P is in the above range 2. 3~5. In the case of 0%, it is more preferable from the viewpoint that the runner P1 becomes the cooling rate before the mold release state, the flow of the molten resin, and the formability. Also need to take out 2 diagonal dimensions (actual size) 5 吋, plate thickness 0. 5mm light guide plate (volume 3 8 76mm3, weight 4. In the case of 65g), when the diameter PI a of the injection hole 44c is selected to be 2. 6 mm, the mold release angle 0 is 1 ° with respect to the center line L, and the runner bushing 44 having the inner diameter 44a of the total length P 1 c is 25 mm, the weight g2 of the runner P1 is 0 as described above. · 2 2 g, the ratio of the runner P 1 is 2 · 4 wt%. The effect of miniaturization and weight reduction of the runner P 1 and the runner P2 is mainly based on the fact that the injection molding and the injection compression molding are performed as described above, and a slow injection speed can be employed, so that it is not necessary to enlarge the runner P 1 . The cross-sectional area is to reduce the flow loss of the molten resin. Further, at the time of injection molding and injection compression molding, the resin in the cavities 14 and 14 is compressed by the opening and closing mold and the mold clamping mechanism to suppress the depression of the resin in the cavities 14 and 14 , so that it is not necessary to The injection device side performs strong holding pressure, and the cooling and hardening of the runner P1 may be performed first, and as a result, it is not necessary to increase the cross-sectional area of the runner P1. In particular, in the form of sprue cutting, the pressure is maintained through the sprue P1 before the sprue is cut, and the holding pressure is stopped after the sprue is cut 24- (22) 200843934, thereby lowering the sprue p 1 The internal pressure causes the runner P1 to be slightly recessed, so that the runner p1 can be more easily released from the runner bushing 44a. A cooling medium flow path 51 for the runner P1 and the flow path P2 is formed around the small diameter portion of the sprue bushing 44. Specifically, the portion of the block 43 facing the sprue bushing 44 is formed in a concave shape so as to have a length of 5 to 10 mm in the direction of the runner P1 and a width of 6 6 mm in the direction orthogonal to the longitudinal direction. Cool the media flow path 5 1 . Between the bushing 44 and the insert 43, there are Ο-shaped rings 5 1 a, 5 1 a for preventing leakage of the cooling medium. In the small diameter portion of the sprue bushing 44, the wall thickness 44e of the portion where the cooling flow path 51 is provided is preferably 20 to 30 mm. In this embodiment, since the entire length of the runner P1 is short (25 mm), the media flow path 5 1 is provided only at one place, but the injection hole side and the flow path connecting portion side can also be cooled. Further, in the present embodiment, although the temperature is controlled as the cooling medium, oil can be used. As shown in Figs. 2 to 4, the flow path forming portion 54 is formed on the surface of the insert 43 facing the movable mold 12 from the flow path portion 44d of the sprue bushing 44 toward the cavity forming portion. Further, the flow path forming ginger is formed at a position of a groove-like stage (a position on the side of the fixed disk) with respect to the abutting surface 46a of the abutting block 46, thereby constituting a surface of the flow path P2 of the fixed mold 13. The width of the flow path forming portion 54 in the direction in which the molten resin flows is gradually widened from the partial cavities 14, 14 adjacent to the sprue bushing 44. In order to maintain the equal interval between the flow path forming portion 54 and the flow path forming portion 32 of the mold 12, the recessed portion is formed by cooling the inner hole and inserting the length of the three-way sprue fitting medium to form a separate water. The direction of the connection to the lower side of the P 54 is directed toward the movable direction of the -25- (23) 200843934 convex portion and the convex portion opposite to the concave portion. The concave portion of the flow path forming portion 54 is connected to the gate forming portion by a continuous same surface. Therefore, the formation portions of the flow path P2 and the gate P3 are not clearly separated from each other. Further, a gate forming portion composed of an end surface of the gate cutting member 24 is formed continuously in the flow path forming portion 32 of the core portion 16. The width of the gate forming portion in the direction orthogonal to the flow direction of the molten resin (the width of the gate cutting member 24) is wider than the diameter of the runner P1. Therefore, the gate P3 of the present embodiment is a type of a film gate, and the length (width) thereof is about 2/3 to 1 / 4 of the length of the side surface of the light guide plate (the side opposite to the light incident surface). And connecting the flow path and the cavity through the aforementioned film gate. A gate cutting member 45 is fixed between the flow path forming portion 54 of the insert block 43 and the main portion forming portion 42a of the cavity forming portion of the cavity forming block 42. The gate cutting member 45 is a rectangular thin plate made of a hard metal member such as an alloy tool steel (SKD steel) having a C scale Rocker hardness of 55 to 63 (HRC), and the hardness ratio thereof is used to form a cavity forming portion. The member of the main portion forming portion 4 2 a is higher. The width of the gate cutting member 45 in the direction orthogonal to the flow direction of the molten resin is the same as or slightly wider than the gate forming portion. The thickness of the gate cutting member 45 is 0. 4~0. 8mm or so. The front surface of the gate cutting member 45 and the cavity forming portion 16a are opposed to each other to constitute a part of the cavity forming portion. At the corner portion of the gate portion side of the gate cutting member 45, a gate cutting tool 45a (cutting blade) is formed. When the gate cutting member 24 of the movable mold 12 advances, the surface on the gate portion side faces the surface opposed to each other with a slight interval therebetween. Next, a molding method (injection molding method) of the molding die 11 of the embodiment -26-(24)(24)200843934 will be described using the flowchart of Fig. 6. In this embodiment, the system uses 4. With a forming cycle time of 2 seconds, the diagonal dimension of the plane direction is 4 吋 and the thickness is 〇. 38mm uniform plate thickness of the light guide plate. Among them, the opening and closing time (including the mold opening time, the take-out time, and the mold closing time) is 1. 4 seconds, intermediate time (including decompression time) 0. 1 second, shot time 0. 05 seconds, holding time 0. 45 seconds, cooling time 2. 2 seconds (substantial cooling is performed from the beginning). Therefore, in the present embodiment, the cooling medium flow path 17 for cooling the cavity forming portion 16a of the movable mold 12, and the cooling medium flow for cooling the vicinity of the protruding pin 2 3 and the flow path forming portion 32 are provided. The cooling medium flow path 50 for cooling the main portion forming portion 42a of the cavity forming portion of the fixed mold 13 is controlled by the temperature regulator to be about 80 to 1 20 °C (ratio forming) The polycarbonate of the resin used has a glass transition temperature Tg of 3 0 to 10 0 ° C) of a cooling medium (cooling water). Further, the temperature of the cooling medium sent to the cooling medium flow path 51 is preferably equal to or lower than the temperature of the cooling medium sent to the cooling medium flow path 50. That is, as shown in Fig. 1, when the cooling water temperature of the cooling medium flow path 51 sent to the sprue bushing 44 is 40 ° C, the sprue bushing 44 is formed at a molding cycle time of 7 seconds or longer. The problem of excessive cooling causes a cold block to be mixed in the molded article. Further, when the temperature difference between the cavity forming blocks 42 of the fixed mold 13 is too large, the difference in thermal expansion between the respective portions causes a problem of transfer, and therefore it is not preferable to perform molding at 40 ° C or lower. When the temperature of the cooling water sent to the cooling medium flow path 51 is 120 ° C, the runner is cut off in 4 seconds. Actually, at this temperature, the runner may be cut off. Forming at this temperature is meaningless. -27- (25) 200843934 In addition, the temperature in the front area of the injection device (the area closest to the nozzle) was set to 305 °C, and the molten resin of polycarbonate was measured. When the polycarbonate is used, the temperature of the front portion of the injection device is set. From the viewpoint of fluidity of the molten resin, it is preferred to set the temperature to a high temperature of 3 20 to 3 80 °C. When the mold clamping cylinder 10 is actuated, the movable mold 1 2 assembled to the movable disk 9 abuts against the fixed mold 13 assembled to the fixed disk 6 to close the mold. At this time, once the core portion 16 is advanced to the most advanced position, the spring 18 is contracted to advance the movable plate 9 or the like to the closed mold completion position (〇 position, the movable frame portion 19 and the mold main portion 15 abut), and then again The movable disk 9 or the like is slightly retracted by the mold clamping cylinder 1 and controlled to stop at the position A at the start of the second drawing. Thereby, the core portion 16 of the movable mold 12 can be stopped at a position closer to the mold opening direction than the forming completion position. When the position of the movable disk is positioned with higher precision by a servo motor or the like, the movable disk can be moved to the position A at the time of starting the ejection. At this time, the position A before the start of ejection of the movable core 9 and the core portion 6 of the movable mold 12 is controlled such that the distance between the cavity forming portion 42a of the fixed mold 13 and the cavity forming portion 16a of the movable mold 12 is controlled. It is equal to the plate thickness of the light guide plate p plus 〇·1~〇. 3mm. Regarding the aforementioned position, with respect to the light guide plate p.  The thickness of the plate, the distance between the cavity forming portion 42 a and the cavity forming portion 16 a is preferably 120% to 200%, and in the case of a thin plate, it is preferably a high number of the above ratio; In the case of a thick plate thickness, it is preferably a low number of the aforementioned ratios. When the position A at the time of starting the ejection is stopped, the mold clamping cylinder 1 of the mold closing mechanism and the mold clamping mechanism is used to generate a slight mold clamping force which does not change the degree of the above position. When the servo motor is used, position control -28- (26) (26) 200843934 is performed and the stop position is stopped. When the movable mold 12 is stopped to form the mold cavities 14, 14 which are connected to the flow path (including the gate having a variable thickness), the inside of the cavities 14, 14 are air-sucked. In the air suction, the electromagnetic opening and closing valve between the vacuum device (not shown) and the air passages 34, 53 is opened, and the gap between the air passage 34 and the core portion 16 and the movable frame portion 19 connected thereto is The air in the cavity 14, 14 is attracted from the air passage 53 and the gap between the cavity forming block 42 and the abutting block 46 connected thereto. The purpose of forming a reduced pressure state in the cavity 14 and 14 before starting the injection is to rapidly flow the molten resin to the light in the cavity 14 and 14 without being resistant to air during the injection. The entrance surface forms the end on the side of the block 20, and the method is thinner (0. 2~1. The light guide plate P of 0 mm) is particularly effective in forming. In the present embodiment, since the nozzle 2b continues to abut against the sprue bushing 44, air is not sucked from the sprue bushing 44 side during decompression. Then, after a predetermined intermediate time (decompression time) has elapsed, the injection mechanism (not shown) of the injection device 3 is actuated to eject the molten resin before the screw in the heating cylinder 2a. The molten resin is ejected into the cavity 14 through the nozzle hole of the nozzle 2b and the runner P1, the flow path P2, and the gate P3 formed by the inner hole 44a of the sprue bushing 44. In the present embodiment, the peak value of the injection speed is set to 200 mm/seC, and the advance speed of the screw is controlled by the servo motor for the injection of the injection mechanism. The injection speed is preferably 150 to 400 mm/sec. When the sheet is formed by injection compression molding, the thickness is formed. 4~1. The same exit speed can also be used for a 0 mm light guide. The above-mentioned ejection speed is 150 to 400 mm/sec, which is lower than the number of 500 mm/sec or more at the time of general injection molding of the same molding -29-(27)(27)200843934. Since the injection holes are filled in the cavities 14 and 14 at such a low ejection speed, the internal stress in the vicinity of the gate of the formed light guide plate P can be reduced. At the time of injection molding, as described above, since the mold clamping force approaches 0, the core portion 16 and the movable disk 9 of the movable mold 12 can be retracted by the injection pressure, and the interval between the mold holes 14 and 14 can be changed. width. After the injection (at substantially the same time as the completion of the injection), the mold clamping cylinder 1 of the opening and closing mold and the mold clamping mechanism is actuated on the side of the mold clamping device 5, and the movable disk 9 and the movable mold 1 2 are moved in the mold closing direction. Thereby, the core portion 16 is advanced with respect to the movable frame portion 19, and the distance between the cavity forming portion 42a of the fixed mold 13 of the cavity 14, 14 and the cavity forming portion 16a of the movable mold 12 becomes short, and the cavity is formed. The molten resin in 14, 14 is compressed. At this time, pressure control is performed on the clamping cylinder 1 ,, and the oil pressure is detected and controlled to 400 KN of the setting 値. In this case, the resin pressure in the mold holes 14 and 14 is about 150 MPa. At this time, the speed of the boost is 〇. 〇 3 seconds high speed boost to set 値. The faster the boosting speed, the better, preferably 0. 02~0. 05 seconds boost. The faster the mold clamping speed is, the better the output is controlled to a peak value of 3 0 0~6 0 0 m m / s e c. Compared with a mechanism using a servo motor, the mechanism using the clamping cylinder 1 , can be started faster at the same scale, and a high-speed clamping speed can be achieved. In the embodiment of the present invention, a light guide plate having a diagonal size of 4 turns is formed, and the mold is clamped at 300 KN. Depending on the situation, it is also possible to perform the mold clamping at the same time as the start of the injection or during the injection (beginning of the injection). At this time, the intervals of the cavity portions 14 and 14 may be almost or completely constant. In addition, by the position control, the movable disk can be moved from the starting position of the opening and closing mold and the mold clamping mechanism to the predetermined position at which the compression is started, or the predetermined clamping force (or the resin can be detected) of 30-(28) (28)200843934. The position of the pressure) is then switched to pressure control. When the screw position reaches the predetermined pressure holding switching position by the injection device, the injection control is switched to the pressure control control of the pressure control. The pressure is preferably 5 to 20 MPa, so that the injection and pressure holding are almost completely free of buffering. In the present embodiment, when a predetermined time elapses, each gate cutting member 24 of the movable mold 1 is advanced by a gate cutting member driving device (not shown). 45~0. 8 mm, and the gates P3 and P3 are cut off. At this time, between the gate cutting tool 24a (cutter) of the gate cutting member 24 of the movable mold 12 and the gate cutting tool 45a (cutter) of the gate cutting member 45 of the fixed mold 13, respectively The gates P3 and P3 are cut. When the gate is cut, the molten resin of the gate P3 does not reach a state of complete hardening. Next, when the gate P 3 is cut by the runner cutting member 24, the runner cutting member 24 is held at the advanced position. In the present invention, even if the pressure holding is not performed by the injection device, the core portion 16 of the movable mold 12 is advanced by the driving of the opening and closing mold and the mold clamping mechanism (the mold clamping cylinder 10), so that the mold holes 14 and 14 can be moved. Since the molten resin in the inside is compressed, even if shrinkage occurs due to cooling, no depression occurs, and good transfer molding can be performed. Then, the core portion 16 advances and finally stops at the position of the plate thickness b of the light guide plate p. On the other hand, the injection device stops the holding pressure, and the measurement can be started after a predetermined time. Further, in the runner P1, since the holding pressure from the injection device 3 is stopped, the pressure in the runner P i can be lowered. Then, the runner P i is cooled and contracted by the cooling medium to be slightly recessed, and a gap is formed between the runner P 14 and the inner hole 44a of the sprue bushing 44, and is matched with the upper -31 (29) 200843934 The hole 44a is subjected to rough surface processing, and the runner P1 is easily released from the mold. In the present embodiment, since the draft angles θ of the runners P 1 with respect to the center line L are each 1 °, it is easier to release the runners P1. When the draft angle is 0, the ratio is too small.  5 ° small), the demolding of the runner P 1 cannot be performed; when the drafting angle Θ is too large (each ratio is larger than 2°), the cooling hardening of the runner P1 near the injection hole 44c progresses, and the flow path portion The cooling hardening of the runner P1 in the vicinity of 44d progresses slowly, so that when the sprue P1 is released from the mold, the possibility that the runner P1 is cut near the flow passage P2 is high. Further, the diameter Pla of the injection hole 44c is 2. 0mm prevents the sprue from being generated when the sprue P1 performs the film mold. When the diameter of the injection hole 44c exceeds 3. When 0 m m, the wire will occur, but it is 1. When the flow loss of the resin is smaller than 6 m m, the emission speed higher than that of the embodiment is required, and the possibility that the light guide plate P is defective is high. After a predetermined period of time, the mold clamping force is lowered, and the air passage 34 between the movable frame portion 19 and the core portion 16 of the movable mold 1 2, the abutting block 46 of the fixed mold 13 and the cavity forming block are formed. The air passage 53 between the 42 and the insert 43 sends the mold release air to the cavities 14, 14 and the flow path P2. Attached to the working and clamping device, the pressure is released and the mold is opened in sequence. At this time, since the flow path P2 integrated with the runner P1 is engaged with the bite portion 23a, when the runner P1 is released from the sprue bushing 44, the flow path P2 is held together with the flow path P2 to be held on the movable mold 1 side. take out. The light guide plates P and P which have been cut by the runner are also taken out while being held on the movable mold 1 side. Further, while the movable mold 12 is stopped at the mold opening completion position, the take-out robot (not shown) is operated, and the projecting pin 2 3 of the ejector unit is advanced. In the embodiment of the present invention, the robot for taking out, which is used in the form of the method of the present invention, can perform the holding of the runner P1 and the flow path P2 and the adsorption of the light guide plate. At the time of the aforementioned take-out, the gate cutting member 24 is in a stopped state at the advanced position. The light guide plate gate P 3 of the present embodiment can be used as a light guide plate even if it is not subjected to finishing processing because it is not a portion constituting the light incident surface. The runner P 1 and the runner P2 account for only a very small weight % as described above, but can be separately recovered and reused. At this time, since the diameter of the runner P1 is small, it can be pulverized by a small pulverizer, so that the ratio of the raw material (v i r g i n m a t e r i a 1) can be improved. Next, the relationship between the diagonal size of the light guide plate and the thickness of the light guide plate and the molding conditions will be described. The relationship between the diagonal size of the light guide plate and the thickness of the light guide plate, although some parts are related to the resin or the molding conditions, cannot be closely distinguished, but can be roughly distinguished as follows. The light guide plate with a diagonal size of 2 to 5 inches can be 0. 3~0. The 5mm range is formed, and depending on the conditions, it may be formed. 2mm or more. Incidentally, the diagonal size is 2吋 and the thickness is 0. The 3mm light guide plate is formed into two cases, the volume is 744mm3, and the weight gl of the molded product is 0. 89g. For a light guide plate with an angular size of 5 to 6 ,, based on the relationship between resin flow and cooling rate, the thickness of the plate should be 0. 3~0. 6mm; the light guide plate with a diagonal size of 6~7吋, the thickness of the plate should be 0. 4~0. 6mm. For example, a 7-inch light guide plate requires a higher injection speed and a higher mold clamping speed because the distance from the gate to the corner farthest from the gate is about 15 cm. When the light guide plate is larger, the temperature of the molten resin should be raised in order to make the resin flow well. Further, in the case of the mold clamping force, it is preferable that the light guide plate having a diagonal size of 2 to 5 Å is formed into one or two, and it is preferably 2 0 0 to 5 0 0 KN, and the case where one of the light guide plates of 6 inches or more is formed is preferably 5 00~1 000 KN. The mold clamping force is determined by considering the light guide plate. -33- (31) (31) 200843934 The shadow area is determined by the peak of the predetermined mold clamping speed of 300 to 600 mm/sec. The molding cycle time of the light guide plate will be described below. Diagonal size 2~5 吋, plate thickness 〇·2~0. 5mm light guide plate is formed in two cases, or the diagonal size is 5~7吋, the plate thickness is 0. 4~0. When a 6 mm light guide plate is formed, the time from the completion of the mold closing to the start of the mold opening (forming time) is 1.75 to 4. 0 seconds, the time from the start of the mold opening and the removal of the light guide plate to the completion of the mold closing (opening and closing time) is 〇.  7 5~2 · 2 seconds, the total forming cycle time can be within 2.6 seconds. Figure 15 shows the invention by compression forming to a minimum of 2. A flow chart of 5 seconds of cycle time to form a light guide plate. Among them, the opening and closing mode time (extraction time, intermediate time) is 0_75 seconds, the injection delay time (boosting time) is 〇·1 second, the injection time is 0 · 0 5 seconds, the holding time is 0 · 4 seconds, cooling The time is 1 · 2 seconds. Further, in the forming of the light guide plate of the present invention, the thickness of the light guide plate is at most 1. Below 0 mm, the dimension of the light guide plate in the planar direction does not affect the forming cycle time. The most influential to the forming cycle time is the thickest runner P 1 (especially the runner connection). If the forming cycle time is further shortened, the cooling time of the runner P 1 is insufficient to cause insufficient hardening and pouring occurs. The cut of the road P 1 . As shown in the flowchart of Figure 16, the diagonal size is 3吋 and the thickness is 〇.  6mm (uniform ^ plate thickness), the light guide plate with transfer pattern can be formed with a cycle time of 6. A 0 second shot was formed by compression molding, and the cooling time was 3 · 9 seconds. The larger the area and thickness of the formed light guide plate, the longer the molding cycle time tends to be. However, if the molding cycle time is further extended, economical problems may occur, for example, when it exceeds 9 to 10 seconds, Problems such as nozzle cooling and deterioration of the resin in the heating cylinder -34- (32) (32) 200843934 occur. According to the present invention, as shown in Fig. 8, the injection mold 61 of the light guide plate of another embodiment can be used for injection compression molding or injection molding. This molding die 61 is a so-called fitting mold. Specifically, after the convex portion of the movable mold 62 is fitted into the concave portion of the fixed mold 66, a slight gap is formed between the fitting surfaces 64b and 65a and the cavity side forming portion 7ia (the molten resin is not leaked), but A cavity 72 is formed between the two dies 62,66. The sprue bushing 69 of the fixed mold 66 can be the same as the embodiment shown in Fig. 2 and the like, and the range that can be changed is also the same. The present invention is not limited to the above-described embodiments, and variations made by those skilled in the art in accordance with the gist of the present invention are of course included in the present invention. In the present embodiment, a molding die for a light guide plate for a mobile phone having a diagonal size of 4 Å is described, but the shape and type of the light guide plate are not limited. Therefore, in addition to the light guide plate having a uniform thickness, a wedge-shaped light guide plate whose thickness is thinner from the light incident surface side to the other side may be used. The wedge-shaped light guide plate is formed at a portion other than the light incident surface to form a gate, and the thickness of the thin side portion can be formed at the above 0. 2~0. Within 6mm range. The incident light can be applied to a side light-type light guide plate that is incident from the side, a backlight-type light guide plate (including a light-diffusing sheet) that is incident from the rear surface and emitted from the front surface, and reflects the external light. Regarding the shapes of the reflecting surface and the light emitting surface, various combinations such as mirrors, pits, grooves, and holograms can be considered. The invention is also applicable to lenses, sheets, and the like that are associated with the incidence or exit of light. In short, the injection molding and the injection compression molding of the present invention are applied to at least one side of the transfer surface. -35- (33) (33) 200843934 The molding die 1 1 described in the present embodiment is an injection molding machine that opens and closes the mold in the horizontal direction. However, the molding die 1 1 can be applied to the opening and closing of the mold in the vertical direction. In the above embodiment, the distance between the cavity forming portion of the fixed mold and the cavity forming portion of the movable mold is changed by the opening and closing mold and the mold clamping mechanism of the injection molding machine to compress the molten resin; Or a hydraulic cylinder for injection molding is provided in the movable mold, and the core portion is moved by the hydraulic cylinder to perform compression of the molten resin. Although the resin used for the molding is only a polycarbonate (for example, Dufflon LC 1 500), other resins having excellent optical properties and fluidity may be used, for example, methacrylic resin (specific gravity 1) . 2), cycloolefin polymer resin (specific gravity 1. 0) Wait. The scope of the light guide plate of the present invention includes a light-transmitting resin plate such as a light diffusion plate. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a front view of an injection molding machine used in a method of molding a light guide plate of the present embodiment. Fig. 2 is a cross-sectional view showing a molding die used in the method of molding a light guide plate of the embodiment, showing a state in which the movable mold is stopped at a position before the start of ejection. Fig. 3 is a cross-sectional view showing a molding die used in the method of molding a light guide plate of the embodiment, showing a state in which the resin in the cavity is compressed. Fig. 4 is a cross-sectional view showing a molding die used in the method of molding a light guide plate of the embodiment, showing a state in which the gate is cut. Fig. 5 is an enlarged view of a main portion of the sprue bushing of Fig. 4. -36- (34) (34) 200843934 Fig. 6 is a flow chart showing a method of forming a light guide plate of the present embodiment. Fig. 7 is a perspective view showing a runner and a flow path obtained by the method for forming a light guide plate of the embodiment. Fig. 8 is a cross-sectional view showing a molding die used in a method of molding a light guide plate according to another embodiment. Fig. 9 is an enlarged side elevational view of the runner obtained by the method of forming a light guide plate of the embodiment. Fig. 10 is a view showing the relationship between the shape of the runner of the light-emitting plate of another embodiment and the shape of the runner and the molding cycle time. Fig. 1 is a view showing the relationship between the shape of the runner of the light-emitting plate of the other embodiment and the shape of the runner and the molding cycle time. Fig. 1 is a view showing the relationship between the shape of the runner of the light-emitting plate of another embodiment and the shape of the runner and the molding cycle time. Fig. 13 is a view showing the relationship between the shape of the runner of the light-emitting plate of another embodiment and the shape of the runner and the molding cycle time. Fig. 14 is a view showing the relationship between the shape of the runner of the light-emitting plate of another embodiment and the shape of the runner and the molding cycle time. Fig. 15 is a flow chart showing a method of forming a light guide plate according to another embodiment. Fig. 16 is a flow chart showing a method of forming a light guide plate according to another embodiment. [Main component comparison table] 1 : Injection molding machine -37- (35) (35) 200843934 3 : Injection device 5 : Clamping device 6 : Fixed plate 9 : Movable disk 1 〇 : Clamping cylinder 1 1 , 6 1 : Molding molds 12, 62: movable molds 13, 66: fixed molds 14, 72: mold holes 15 and 4: mold main body portion 16: core portions 16a, 42a: cavity forming portions 1 9 : movable frame portions 24 45: gate cutting members 44, 69: sprue bushing 44a: inner hole 44b: nozzle contact faces 44c, 69a: injection hole 44d: flow path connecting portions 17, 33, 50, 51, 68b, 70a: Cooling medium flow path P: light guide plate P1: runner P 1 a : diameter of injection hole P 1 b : diameter of flow path connection portion - 38 - (36) 200843934 P 1 c : full length P2 : flow path P 3 : poured Mouth-39

Claims (1)

  1. 200843934 (1) 十、申請專利範圍 1 · 一種導光板之成形模具,係在形成於固定模具和 可動模具間的模穴形成部內進行導光板的成形之導光板之 成形模具,其特徵在於:係具備·· 模穴形成部,可壓縮成形出成形品容積爲7.8cm3以 下的導光板; 澆道襯套,經由流道形成部連接於前述模穴形成部, f 其注入孔的直徑爲1.6〜2.6mm,流道連接部的直徑爲 3.6mm以下,且具備對中心線具有脫模傾斜角度之內孔; 冷卻媒體流路,配設於該澆道襯套的周圍,和用來冷 卻前述模穴形成部之冷卻媒體流路分別獨立形成。 2·如申請專利範圍第1項之導光板之成形模具,其 中,前述澆道襯套之內孔對中心線的脫模傾斜角度爲0.5° 〜2〇。 3 · —種導光板之成形模具,係在形成於固定模具和 可動模具間的模穴形成部內進行導光板的成形之導光板之 成形模具,其特徵在於:係具備: 模穴形成部,可壓縮成形出成形品容積爲7.8cm3以 下的導光板; 澆道襯套,經由流道形成部連接於前述模穴形成部, 其具備注入孔及流道連接部; 前述注入孔及流道連接部之至少一方爲非正圓形,其 面積在相當於根據申請專利範圍第1項所記載之注入孔直 徑所算出之注入孔面積的範圍內,或在相當於根據流道連 -40- (2) 200843934 接部之直徑所算出之流道連接部面積的範圍內。 4. 如申請專利範圍第1至3項中任一項之導光板之 成形模具,其中,前述澆道襯套的內孔係實施粗面化處 理。 5. 一種導光板之成形方法,係在形成於固定模具和 可動模具間的模穴形成部內進行導光板的成形之導光板之 成形方法,其特徵在於:係具備: 模穴形成部,可壓縮成形出成形品容積爲7.8cm3以 下的導光板; 澆道襯套,經由流道形成部連接於前述模穴形成部, 其注入孔的直徑爲1 . 6〜2.6 m m,流道連接部的直徑爲 3.6mm以下,且具備對中心線具有脫模傾斜角度之內孔; 冷卻媒體流路,配設於該澆道襯套的周圍,和用來冷 卻前述模穴形成部之冷卻媒體流路分別獨立形成; 經由前述澆道襯套射出熔融樹脂,藉由開閉模及合模 機構來壓縮模穴形成部內之熔融樹脂,並藉由前述獨立配 設之冷卻媒體流路來冷卻澆道。 6. 如申請專利範圍第5項之導光板之成形方法,其 中,送往前述獨立配設之冷卻媒體流路之冷卻媒體的溫 度,係設定爲送往用來冷卻模穴形成部之冷卻媒體流路之 冷卻媒體的溫度以下。 7. 如申請專利範圍第5或6項之導光板之成形方 法,其中,射出速度爲150〜400mm/sec。 8 .如申請專利範圍第5至7項中任一項之導光板之 -41 - 200843934 (3) 成形方法,其中,以射出裝置之噴嘴持續抵接於澆道襯套 的狀態進行連續成形。200843934 (1) X. Patent Application No. 1 A forming mold for a light guide plate is a forming mold for a light guide plate for forming a light guide plate in a cavity forming portion formed between a fixed mold and a movable mold, and is characterized in that: The cavity forming portion is configured to compress and form a light guide plate having a molded product volume of 7.8 cm 3 or less; the runner bushing is connected to the cavity forming portion via a flow path forming portion, and the diameter of the injection hole is 1.6 2.6 mm, the diameter of the flow path connecting portion is 3.6 mm or less, and has an inner hole having a relief angle to the center line; a cooling medium flow path disposed around the sprue bushing, and used to cool the mold The cooling medium flow paths of the hole forming portions are formed separately. 2. The molding die of the light guide plate of claim 1, wherein the inner hole of the sprue bush has a release angle of 0.5 to 2 对 to the center line. (3) A molding die for a light guide plate is a molding die for a light guide plate that forms a light guide plate in a cavity forming portion formed between a fixed mold and a movable mold, and is characterized in that: a cavity forming portion is provided a light guide plate having a molded product volume of 7.8 cm 3 or less is compressed and formed; the sprue bushing is connected to the cavity forming portion via a flow path forming portion, and includes an injection hole and a flow path connecting portion; and the injection hole and the flow path connecting portion At least one of them is a non-circular circle, and the area thereof is in a range corresponding to the area of the injection hole calculated according to the diameter of the injection hole described in the first item of the patent application range, or is equivalent to a flow-through--40- (2) ) 200843934 The area of the runner connection area calculated by the diameter of the joint. 4. The forming mold for a light guide plate according to any one of claims 1 to 3, wherein the inner hole of the sprue bushing is subjected to a roughening treatment. A method of forming a light guide plate, which is a method of forming a light guide plate for forming a light guide plate in a cavity forming portion formed between a fixed mold and a movable mold, comprising: a cavity forming portion, which is compressible a light guide plate having a molded product volume of 7.8 cm 3 or less is formed; a sprue bushing is connected to the cavity forming portion via a flow path forming portion, and a diameter of the injection hole is 1.6 to 2.6 mm, and a diameter of the flow path connecting portion It is 3.6 mm or less, and has an inner hole having a release angle to the center line; a cooling medium flow path disposed around the sprue bushing, and a cooling medium flow path for cooling the cavity forming portion, respectively The molten resin is injected through the sprue bushing, and the molten resin in the cavity forming portion is compressed by the opening and closing mold and the mold clamping mechanism, and the runner is cooled by the independently disposed cooling medium flow path. 6. The method of forming a light guide plate according to claim 5, wherein the temperature of the cooling medium sent to the independently disposed cooling medium flow path is set to be sent to a cooling medium for cooling the cavity forming portion. The temperature of the cooling medium of the flow path is below. 7. The method of forming a light guide plate according to claim 5 or 6, wherein the injection speed is 150 to 400 mm/sec. 8. The light guide plate according to any one of claims 5 to 7, wherein the nozzle is continuously formed while the nozzle of the injection device continues to abut against the sprue bushing.
TW96128222A 2007-05-15 2007-08-01 TWI318166B (en)

Priority Applications (2)

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JP2007129670 2007-05-15
JP2007185124A JP4047917B1 (en) 2007-05-15 2007-07-16 Light guide plate mold

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CN101659094B (en) * 2008-08-27 2012-06-13 鸿富锦精密工业(深圳)有限公司 Molding mould
KR101394846B1 (en) 2011-12-09 2014-05-13 더 재팬 스틸 워크스 엘티디 Molding method of thin molded article
CN102691511B (en) * 2011-03-21 2014-07-16 山东大学 Cavity forming apparatus for embedded chamber of underground engineering test model
US8944697B2 (en) 2012-09-28 2015-02-03 Positronic Industries, Inc. Fiber optic connector assembly
WO2016151437A1 (en) * 2015-03-23 2016-09-29 Sabic Global Technologies B.V. Part ejection system for injection molding apparatus
CN105751440A (en) * 2016-04-29 2016-07-13 荔浦华美塑料有限公司 Mold capable of promoting sorting of injection molding products

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