200827796 (1) 九、發明說明 【發明所屬之技術領域】 本發明係關於小型導光板之射出壓縮成形方法、射出 壓縮成形模具、以及小型導光板，特別是關於行動電話用 的導光板之射出壓縮成形方法、射出壓縮成形模具、以及 小型導光板。 【先前技術】 液晶、電漿、有機EL等的顯示裝置所使用之導光板 ，一般係藉由射出成形或其中之射出壓縮成形來進行。當 藉由射出壓縮成形來進行導光板之成形時，爲了提高生產 效率，期望能縮短成形循環時間。導光板之成形循環時間 ，係取決於其大小與板厚。專利文獻1之1 8吋、厚1 2mm 之導光板，必須1 60秒以上的成形循環時間。另一方面， 行動電話用之小型導光板，一般必須1 〇數秒的成形循環 時間。幾乎沒有任何公知文獻提到小型導光板之成形循環 時間，只有專利文獻2提到一點點。專利文獻2係成形出 1〜8吋的導光板，其揭示「保壓較佳爲，以峰値壓力之 2/3〜1/3左右的壓力施加0.3〜1.5秒後，進一步用更低的 壓力施加數秒」。通常除保壓時間以外，必須花更長的冷 卻時間，又再加上射出時間、開閉模時間、取出時間等等 ，整個成形循環時間據推測必須1 〇數秒。特別是小型導 光板的情形，關於將模具構造和各種冷卻媒體流路組合以 對澆道等各部位進行冷卻之構想，以往未曾出現。 -4 - 200827796 (2) 〔專利文獻1〕日本特開2005- 349646號公報（段落 〔0027〕，表 1) 〔專利文獻2〕日本特開2004- 161975號公報（段落 (0130 ]〜〔0133〕) 【發明內容】 本發明係有鑑於上述問題點而構成者，其目的係提供 一種射出壓縮成形方法以及射出壓縮成形模具，在藉由射 出壓縮成形來成形出小型導光板時，能縮短小型導光板之 成形循環時間。另一目的係提供一種小型導光板之射出壓 縮成形方法以及射出壓縮成形模具，可縮短小型導光板之 成形循環時間並成形出光學性能優異的導光板。另一目的 係提供一種小型導光板之射出壓縮成形方法，可縮短小型 導光板之成形循環時間，並提昇導光板相對模具之脫模性 〇 本發明之請求項1所記載之小型導光板之射出壓縮成 形方法，係對角尺寸1吋〜5吋、最厚部分之板厚〇.25mm 〜1.0mm以下之小型導光板之射出壓縮成形方法，其特徵 在於：藉由固定模具之模穴形成面及可動模具之模穴形成 面來形成容積及板厚可變之模穴，前述固定模具之模穴形 成面及可動模具之模穴形成面係藉由冷卻媒體流路進行冷 卻，且任一方之模穴形成面上具有轉印面；澆道襯套或澆 口部形成面之至少一方係藉由與前述模穴形成面之冷卻媒 體流路不同的冷卻媒體流路進行冷卻；用前述模穴以1成 -5- 200827796 (3) 形循環時間2 · 5秒〜6秒來成形出小型導光板。 依據本發明之小型導光板之射出壓縮成形方法，係對 角尺寸1吋〜5吋、最厚部分之板厚0.25mm〜l.〇mm以下 之小型導光板之射出壓縮成形方法，藉由固定模具之模穴 形成面及可動模具之模穴形成面來形成容積及板厚可變之 模穴，前述固定模具之模穴形成面及可動模具之模穴形成 面係藉由冷卻媒體流路進行冷卻，且任一方之模穴形成面 上具有轉印面；澆道襯套或澆口部形成面之至少一方係藉 由與前述模穴形成面之冷卻媒體流路不同的冷卻媒體流路 進行冷卻；用前述模穴以1成形循環時間2 · 5秒〜6秒來 成形出小型導光板。因此，能大幅縮短成形循環時間。 【實施方式】 參照第1圖至第14圖來說明本發明的小型導光板之 射出壓縮成形方法。第1圖係本實施形態之小型導光板之 射出壓縮成形方法所使用之射出壓縮成形模具之截面圖， 其顯示合模力尙未作用時的狀態。第2圖係本實施形態之 小型導光板之射出壓縮成形方法所使用之射出壓縮成形模 具之截面圖，其顯示合模力作用後的狀態。第3圖係顯示 本實施形態之小型導光板之射出壓縮成形方法所使用之射 出壓縮成形模具之可動模具之前視圖。第4圖係本實施形 態之小型導光板之射出壓縮成形方法所使用之射出壓縮成 形模具之固定模具之前視圖。第5圖係本實施形態之小型 導光板之射出壓縮成形方法所成形出之小型導光板之立體 -6 - 200827796 (4) 圖。第6圖至第8圖係顯示本實施形態的小型導光板之射 出壓縮成形方法之流程圖。第9圖係顯示本實施形態的小 型導光板之射出壓縮成形模具之澆道襯套之放大截面圖。 第1 〇圖至第1 4圖係顯示本實施形態的小型導光板之射出 壓縮成形模具之澆道形狀和成形循環時間的關係。 未圖示之射出壓縮成形機，係將具備加熱筒（內設螺 桿）、噴嘴之射出裝置以及合模裝置，配設於機床上。合 模裝置，係在固定於機床之固定盤（裝設有固定模具13) 和配設於機床之受壓盤之間，配設4根繫桿。裝設有可動 模具1 2之可動盤，係以可移動的方式組裝於前述繫桿。 在受壓盤上，配設用來進行開閉模及合模之合模汽缸（開 閉模及合模機構），前述合模汽缸之衝柱係固定在可動盤 的背面。本實施形態之合模汽缸，係藉由伺服閥之控制將 壓送油送往助力汽缸（截面積較小）而使可動盤能以高速進 行閉模。在開模時，藉由伺服閥之控制將壓送油送往開模 側油室（截面積較小）而能以高速進行開模。在本實施形態 ，其最高規格爲在開模閉模側都能以〇. 3秒進行開閉模。 在本實施形態之開閉模及合模機構，雖是使用藉由伺服閥 控制之合模汽缸，但也能使用含有伺服馬達（起動旋轉驅 動速度及停止速度優異）和滾珠螺桿之肘節機構。這時也 能實現前述速度。又關於射出裝置，其射出速度可在 100mm/s〜400mm/s之間，且能以〇·〇5秒進行射出。 本實施形態之小型導光板之射出壓縮成形模具11，係 用來進行對角尺寸2吋、板厚〇 · 6mm之行動電話用側光型 200827796 (5) 導光板之成形。射出壓縮成形，係在成形開始時至成形結 束時的期間可改變可動模具1 2和固定模具1 3間的距離。 因此，在閉模位置射出熔融樹脂後，使可動模具前進而進、 行壓縮之所謂「射出模壓」形式，也屬於射出壓縮成形。 在射出壓縮成形，相較於成形完成時，由於開始射出前或 開始射出後模穴呈稍打開的狀態，故不須使用具有高速射 出能力之射出裝置，而能以較低速、低壓來射出熔融樹脂 。由於能以較低速、較低壓來射出熔融樹脂，故在澆口附 近不會發生內部應力。又在開始射出後，使可動模具朝合 模方向移動以壓縮熔融樹脂，因此在模穴之離澆口部較遠 的位置能加快熔融樹脂的流動，以良好地進行微細圖案的 轉印。又由於利用合模力來壓縮模穴內之熔融樹脂，可縮 短保壓時間，能使射出裝置在保壓後儘快轉移至計量步驟 ，而能縮短成形循環時間。這種射出壓縮成形，特別適用 於板厚較薄（相較於平面部的面積）之小型導光板（以下簡稱 、 導光板）的成形。 第1圖、第2圖係本發明的射出壓縮成形模具1 1之 截面圖，分別爲第3圖、第4圖之A - A線截面圖。如前 述第1圖至第4圖所示，射出壓縮成形模具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所組成，在 合模後之兩模具1 2、1 3之間形成容積及板厚可改變之模 穴1 4。在安裝於未圖示的射出壓縮成形機之可動盤的可動 模具1 2上，設置模具本體部丨5、模芯部1 6、可動框部1 7 。在模具本體部1 5之可動盤側安裝隔熱板1 8，在內部配 -8- 200827796 (6) 設頂出用汽缸2 1，其能透過頂出片1 9使突出銷20進行前 後移動。在本實施形態，在突出銷20的前端設置截面Z 字形的咬入部20a，以使導光板P(包含澆口部P1、澆道 P2)容易保持於突出銷20。又頂出用汽缸21係藉由油壓汽 缸或伺服馬達而作動。 在模具本體部1 5之固定模具側的面之上下四部位’ 形成有凹部2 2，彈簧2 3以朝向前述固定模具側的方式安 裝於該凹部22內。又前述彈簧23之前述固定模具側，係 抵接於支持板24 (構成可動框部17的一部分）。又在模具 本體部1 5之前述固定模具側面之前述凹部22的內側，在 上下四部位形成導孔25。從支持板24朝模具本體部1 5設 置之導桿26，係插設於前述導孔25中。因此，設置成與 模具本體部15平行之可動框部17(包含支持板24)，係受 前述導桿26和導孔25之導引，並藉由彈簧32來改變兩 者的間隔。 k 在模具本體部15之固定模具側面之大致中央，固設 模芯部1 6。本實施形態之模芯部1 6，係呈與導光板p的 本體部P4相同之大致四角形（具有去角部分及凸部）。模 芯部1 6之與固定模具丨3相對向的面，係形成光出射面之 面’而構成鏡面之模穴形成面2 7。在模芯部1 6的內部， 形成與前述模穴形成面27平行之複數條的冷卻媒體流路 2 8。在第1圖、第2圖，模芯部1 ό係由一體的塊體所形 成’但形成模穴形成面的部分和其他部分也能由獨立的塊 體所形成。又模穴形成面2 7雖揭示鏡面的例子，但也能 -9- 200827796 (7) 是實施凹槽或粗面加工等而構成者。 在支持板24之固定模具側的面上，以包圍前述模芯 部16周圍的方式配設框體部29。換言之，在由可動部 17(支持板24及框體部29)所形成之空洞部中配設模芯部 1 6。藉由前述彈簧23，能使可動框部1 7全體相對於模具 本體部15及模芯部16在開閉模方向進行移動。第1圖顯 示合模力尙未作用，彈簧23伸長時之可動模具1 2的狀態 ;第2圖顯示合模力作用時，彈簧23收縮後之可動模具 1 2的狀態。 如第1圖至第3圖所示，框體部29係由4個框體部 3 0、3 1、3 2、3 3所構成。其中，第1框體部3 0、第2框 體部3 1，係朝與開閉模方向正交的方向移動之框體；第3 框體部3 2、第4框體部3 3，係無法移動而固定於支持板 24之框體。第3圖之位於模芯部16上方之第1框體部3 0 的移動機構，係在支持板24的上面，以朝向固定模具側 . 的方式突設汽缸安裝部34，在該汽缸安裝部34的上面固 設2個汽缸3 5的汽缸部。又貫穿汽缸安裝部3 4之各孔而 朝下設置各汽缸3 5之桿部，各桿部都安裝在第1框體部 3 0的上面。因此，第1框體部3 0，藉由汽缸3 5之作動能 朝與開閉模方向正交的方向移動，亦即能從模穴形成位置 向後退。 第3圖之位於模芯部1 6右側之第2框體部3 1之移動 機構，係在支持板24之固定模具側之一方’朝向固定模 具側突出固設彈簧安裝部3 6。在前述彈簧安裝部3 6之內 -10- 200827796 (8) 側形成凹部3 7、3 7，在該凹部3 7、3 7內以朝向第2框體 部31的方式安裝彈簧38、38。第2框體部31，係受未圖 示之導槽所導引，且支持板24或第4框體部33的一部分 係構成前進側之制動件，使其在第3圖之左右方向只能稍 微移動。第2框體部3 1，受到彈簧3 8、3 8之彈壓而持續 位於模穴形成位置。設計成能用彈簧來移動第2框體部3 1 的理由在於，爲了避免熔融樹脂造成之模具（特別是模芯 部16)的熱膨脹而使可動部發生咬接。 第3圖中之位於模芯部1 6左側之第3框體部3 2，係 固設於與第2框體部31形成左右對稱的位置。在第3圖 中位於模芯部1 6下方之第4框體部3 3，形成有連續於模 穴形成面27的中央下側之澆口部形成面3 9。又在前述澆 口部形成面39之中央部形成貫通孔40，在該貫通孔40以 能前後移動的方式配設頂出用之突出銷20，又在第4框體 部3 3之突出銷20的周圍，在澆口部形成面3 9之附近形 成冷卻媒體流路46。 如第3圖所示，前述第1框體部3 0、第2框體部3 1 、第3框體部3 2、第4框體部3 3之與固定模具13相對向 的面中，與模穴14鄰接之對向面30a、31a、32a、33a， 在合模而形成模穴時，爲了避免產生毛邊並形成可讓空氣 流通之小間隔，係高精度地加工成比其他部分的平面度更 高。又在前述對向面3 0 a、3 1 a、3 2 a、3 3 a之外側，以包 圍模穴14及後述之獨立塊體43的方式形成空氣通路30b 、3 1 b、3 2b、3 3 b。其外側部分係構成和固定模具1 3抵接 -11 - 200827796 Ο) 之面。又前述第1框體部30、第2框體部31、第3框體 部3 2、第4框體部3 3之鄰接於模芯部1 6且順沿開閉模方 向之內側面，係構成模穴形成面30c、31c、32c、33c(用 來形成第5圖所示導光板P之側面P9)。模穴形成面33c 係包含形成導光板P的澆口部P 1之面3 3 e。前述模穴形 成面3 0 c、3 1 c、3 2 c、3 3 c之連接於固定盤側之內側面， 係和模芯部1 6的外側面隔著些微間隔相對向，以避免發 生咬接。 在第1框體部30之模穴形成面30c中，用來形成導 光板P的光入射面P3之光入射面形成面42，係設於獨立 的塊體43，藉由螺栓將該塊體43以可拆裝的方式固接於 第1框體部3 0之其他部分。在本實施形態，構成模具之 模穴的構件係硬質不鏽鋼製，其熱傳導率爲20〜24 W/(m • K)。 本實施形態之導光板P，係在2處形成有從本體部P4 稍微突出之光入射部P 5，光入射部P 5之端面，係在板厚 方向形成凹槽（縱槽）P3a而構成光入射面P3。在本實施形 態，光入射面P3之凹槽P3a之山部頂點和谷部的高度差（ 深度）爲80 μιη。因此形成光入射面P3之塊體43，也在2 處具有光入射面形成面42、42(形成與模穴14的壓縮方向 (開閉模方向）平行之凹槽）。又在塊體4 3之光入射面形成 面42之凹槽形成部分在壓縮方向之長度，係和導光板ρ 之入射光面Ρ3的板厚Ρ6相同。換言之，僅在射出壓縮完 成時從模芯部1 6之模穴形成面2 7露出於模穴側的部分形 -12- 200827796 (10) 成凹槽。又在射出壓縮完成時模芯邰1 6的側面和塊體4 3 的側面之相對向部分，兩者皆由平面構成。其理由在於， 若在模芯部1 6之側面也形成凹槽’爲了和塊體43之凹槽 嚙合兩者都必須要求高加工精度；又當塊體43之側面全 面都形成凹槽，模芯部1 6之側面全面都形成平面時，在 前述凹槽和前述平面所形成之間隙會發生毛邊。 又在本實施形態，光入射面形成面42雖是由凹槽構 成，但也能選自：凸點、形成有多數個三角錐或四角錐的 面；經實施噴砂加工之粗面；曲面等等平面以外之非平面 所構成者。 如第3圖所示，在可動模具12形成有空氣通路44、 45，以在射出前吸引模穴14內的空氣，並在包含排壓之 脫模時將壓縮空氣噴吹至模穴14內。空氣通路44、45, 係經由未圖示之各閥部連接至真空裝置及壓縮空氣供應裝 置。空氣通路44，係從第1框體部30之孔44a連通於對 向面上所形成之空氣通路30b。空氣通路30b，係連通於 同樣在對向面上所形成之空氣通路3 lb、32b、3 3b。因此 ，空氣通路30b、31b、32b、33b之壓縮空氣，通過由鄰 接的對向面 30a、31a、32a、33a、43a和後述之固定模具 1 3的對向面5 3 a、對向面5 5 a等所形成之間隙（分模面）， 可向模穴1 4內噴吹，或從前述間隙進行吸引。又壓縮空 氣之一部分，會從第1框體部3 0和塊體4 3所形成之間隙 噴吹。形成於第3框體部32之空氣通路45，係連通於模 芯部1 6和各框體部3 0、3 1、3 2、3 3間所形成之空氣通路 -13- 200827796 (11) 30d、31d、32d、33d。因此，空氣通路 30d、31d、32d、 3 3 d之壓縮空氣，通過模芯部1 6之外側面和各框體部3 0 、31、32、33的內側面及塊體43之光入射面形成面42等 所形成之間隙，可向模穴14內噴吹，或從前述間隙進行 吸引。因此，壓縮空氣可從鄰接於光入射面形成面42之 間隙向模穴1 4內噴吹。 在本實施形態，設計成第1框體部3 0可從模穴形成 位置（抵接於第2框體部13而在模穴14周圍形成連續框 體的位置）向外側後退移動之目的在於，爲了容易使導光 板P容易從可動模具1 2進行脫模，而避免弄傷導光板P 之光入射面P 3。在本實施形態，僅使具有光入射面形成 面42之塊體43相對於第1框體部30形成拆裝自如的理 由在於，藉由更換塊體43以謀求降低成本。本實施形態 ，雖是採用框體部29相對於模芯部1 6可在開閉模方向移 動之所謂平抵型模具，但也能採用所謂嵌合型模具，亦即 1 在模穴側模具（具有凹部的模具）能嵌合模芯側模具（具有凸 部的模具）之形式。 其次說明固定模具13，如第1圖、第2圖及第4圖所 示，固定模具1 3係具備：模具本體部5 1、冷卻媒體流路 形成塊52、第1抵接塊53、模穴形成塊54、第2抵接塊 55、澆道襯套56等等。在模具本體部51之固定盤側安裝 隔熱板57，在中央部形成供插入射出裝置噴嘴（未圖示）之 孔58，在其周圍安裝定位環59。在模具本體部51之可動 模具側安裝：冷卻媒體流路形成塊52、澆道襯套56之嵌 -14- 200827796 (12) 塊（第2抵接塊55)。在模具本體部51，設有供插入可動模 具12的導桿41之導孔60。第9圖係澆道襯套56之放大 截面圖，澆道襯套5 6之內孔56b，係從噴嘴抵接側之注入 孔56a朝向流道連接部56c(連接於流道部）形成錐狀擴徑 。在本實施形態，相對於一點鏈線所代表之中心線L之錐 角（脫模傾斜角度）0爲Γ。 冷卻媒體流路形成塊52，係以和模穴1 4平行的方式 在內部形成複數條的冷卻媒體流路6 1。在冷卻媒體流路形 成塊52之可動模具側固設第1抵接塊53，其具有與可動 模具1 2之第1框體部3 0等相對向之對向面5 3 a。又在冷 卻媒體流路形成塊52之可動模具側且在前述第1抵接塊 53之內側，藉由螺栓將模穴形成塊54固定成拆裝自如。 模穴形成塊54之與可動模具1 2相對向的面，係構成模穴 形成面62(用來形成導光板P的反射面（背面）P8)，在本實 施形態，於模穴形成面62上施加有微細的凹凸加工。具 體而言係藉由噴砂而加工成，越靠近固定模具13之塊體 43側（上側）形成更多的凹凸’亦即在反射面P8上，越靠 近光入射面P 3側形成更高密度之微細凹凸。又關於模穴 形成面62，可形成凹槽亦可形成鏡面。採用可拆裝自如的 塊體作爲模穴形成面62的理由在於，和入射光面形成面 42之塊體43同樣的，藉由更換模穴形成塊54即可對應於 模穴形成面62之摩耗或各種導光板P之反射面形狀的測 試。此外，可在固定模具1 3之模穴形成面6 2、可動模具 12之模穴形成面27中至少一方安裝壓模。藉由模穴形成 -15- 200827796 (13) 面27、62之任一方來形成光出射面或反射面亦可。 第2抵接塊55之對向面55a及第1抵接塊53之對向 面5 3 a，係和可動模具丨2之第1框體部3 0、第2框體部 3 1、第3框體部32、第4框體部3 3相對向。在第2抵接 塊55的內部，配設有圓筒形之澆道襯套56。澆道襯套56 之固定盤側面對前述模具本體部5 1的孔5 8，可動模具側 則和突出銷20相對向。在前述澆道襯套56和其外周側之 第2抵接塊55之間，圍繞澆道襯套56周圍之用來冷卻澆 道部P2之冷卻媒體流路63，係藉由和冷卻媒體流路6 1 不同的系統來控制，其兩側被0型環密封而形成冷流道（ 包含澆道）形式。又澆道襯套56之內周面，係藉由噴砂實 施粗面加工，以使澆道P2之脫模變容易。關於固定模具 1 3之澆口部形成面，雖可用其他的冷卻媒體流路來進行冷 卻，但以在澆道襯套5 6周圍設置冷卻媒體流路63之效率 較佳。 又在模穴形成塊54形成有空氣通路64，以在射出前 對模穴14內之空氣進行吸引，並在脫模時（包含排壓時）噴 吹壓縮空氣。空氣通路64係經由未圖示之各閥而連接於 真空吸引裝置及壓縮空氣供應裝置。空氣通路64係連通 於空氣通路64 a(形成於模穴形成塊54和第1抵接塊53之 間）和空氣通路64b(形成於模穴形成塊54和第2抵接塊55 之間）。經由前述空氣通路64a、64b，從模穴形成塊54與 第1抵接塊53及第2抵接塊55之間隙對模穴14噴吹壓 縮空氣，又在射出前吸引模穴1 4內的空氣。藉由使模穴 -16- 200827796 (14) 形成塊5 4之外緣形成比導光板P的外形小，可對轉印面 之模穴形成面62噴吹更多的壓縮空氣。 其次說明使用本實施形態的射出壓縮成形模具1 1之 射出壓縮成形方法。如前述般本發明能藉由一般的射出成 形方法來據以實現，但以其中之射出壓縮成形方法爲最佳 的實施形態。如第6圖所示，在本實施形態，係以4秒的 成形循環時間來成形出對角尺寸2吋、板厚0.6mm之導光 板。其中，開閉模時間（包含取出時間、中間時間）1_3 5秒 ，射出時間0.05秒，保壓時間0.4秒，冷卻時間2.2秒（ 實質上冷卻是從射出開始才進行）。因此在本實施形態’ 在可動模具1 2之模芯部1 6之冷卻媒體流路2 8、突出銷 20及澆口部形成面3 9附近之冷卻媒體流路46、固定模具 1 3之冷卻媒體流路形成塊52之冷卻媒體流路6 1、澆道襯 套5 6附近之冷卻媒體流路63，係流過被調溫器控制成 1 00 °C之冷卻媒體（冷卻水）。又關於冷卻水的溫度，宜爲 50〜1 1 0 °C，較佳爲比成形用樹脂之聚碳酸酯的玻璃轉化 溫度Tg(145°C〜150°C )低40〜100°C。亦即如第 1 1圖所 示，當流過澆道襯套56之冷卻媒體流路63的冷卻水溫度 爲40 °C時，在7秒以上的成形循環時間，澆道襯套56會 過度冷卻而發生在成形品中混入冷料塊之問題。又在與固 定模具1 3之模穴形成塊5 4間之溫度差過大時，除發生熱 膨脹差的問題外，且會有轉印上的問題，因此不宜在40 °c 以下成形。又當流過前述冷卻媒體流路63之冷卻水溫度 爲1 20°C時，在成形循環時間4秒的情形會發生澆道切斷 -17- 200827796 (15) ，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。又在以往一般的導光板成形 模具，並未在澆口 P 1附近或澆道P2附近進行冷卻。然而 在本實施形態，針對澆口部P2及澆道部P2，係用和模穴 形成面27、62大致相同溫度來進行冷卻。又在本發明， 相對於模穴形成面27、62，使澆口部P1及澆道部P2具 有-60 °C〜+20 °C之溫度差，以確保射出時熔融樹脂之流 動性，並減少導光板P之澆口附近部P1 1和澆口遠方部 P 1 2之板厚差，而謀求成形循環時間之縮短。 當澆口 P 1之冷卻溫度低於模穴成形面27、62之冷卻 溫度的程度超過-60 °C時，射出時樹脂的流動變差，會對 模穴14內之射出充塡造成阻礙，而如前述般在導光板p 之澆口部附近P 1 1和澆口遠方部P 1 2之板厚發生差距。相 對於模穴形成面之冷卻溫度，當澆口部形成面3 9及澆道 襯套56之冷卻溫度超過+20°C時，澆道部P2之冷卻硬化 % 變慢，當可動模具12進行開模後將澆道部P2從澆道襯套 5 6拔出時’可能造成澆道部P2之切斷，結果導致成形循 環時間延長。又澆口部形成面3 9及澆道襯套5 6之冷卻溫 度，較佳爲比模穴形成面之冷卻溫度更低溫。在本發明， 除模穴形成面27、62以外，固定模具13之澆道襯套56 和可動模具1 2之澆口部形成面3 9之至少一方，係藉由和 冷卻媒體流路28、6 1不同系統之冷卻媒體流路63 ' 46施 以冷卻，以確保澆口部P1之樹脂流動性。然而當澆道襯 套及澆口部形成面並未另外設置冷卻媒體流路時，和澆口 -18- 200827796 (16) 部形成面及澆道襯套之冷卻溫度過高的情形同樣的’會造 成成形循環時間延長；又在降低模具全體的冷卻溫度時’ 會導致模穴形成面之轉印不足。此外，亦可改變固定模具 1 3之冷卻媒體流路及可動模具1 2之冷卻媒體流路2 8的溫 度，以調整導光板P之彎曲及雙折射率等。另外’亦可在 可動模具設置能前後移動之澆口切斷具，在開模前進行澆 口切斷，以將小型導光板P和澆口部P 1分離。 又射出裝置之前部區域（最接近噴嘴之區域）的溫度設 定爲310 °C，並進行聚碳酸酯之熔融樹脂之計量。在使用 聚碳酸酯的情形，前述射出裝置之前部區域的溫度設定宜 爲3 00〜3 80 °C。接著使未圖示之合模裝置作動，使安裝於 可動盤之可動模具12(第1圖所示的狀態）抵接於安裝在固 定盤之固定模具13。這時，固定模具13之第1抵接塊53 和第2抵接塊5 5所形成之框狀部分，係和可動模具1 2之 第1框體部3 0、第2框體部3 1、第3框體部3 2、第4框 ί 體部33所構成之框體部29抵接，在其內部形成含有澆口 部形成面39(連接於澆道部Ρ2)之模穴14。在形成模穴14 時，將閥打開以使空氣通路44、45、64連通於真空吸引 裝置，並對模穴1 4內的空氣進行吸引。又在本實施形態 ，爲了縮短成形循環時間，未圖示之射出裝置的噴嘴係持 續抵接於澆道襯套5 6。 關於模具抵接後射出開始前之合模力，必須是克服彈 簧23之彈壓力而使可動模具12之模具本體部15和可動 框部1 7之支持板24相抵接之模合力，在本實施形態爲5 〇 -19- 200827796 (17) 部 具 而 可 13 隔 14 寬 置 後 12 熔 對 量 動 更 至 供 lb 定 〜lOOkN。如第2圖所示使支持板24抵接於模具本體 1 5，這時相對於模芯部1 6框體部29位於最後退的位置 接著從未圖示之射出裝置的噴嘴透過澆道襯套5 6以1 00 400mm/SeC的射出速度射出熔融樹脂。可動盤、可動模 1 2之模具本體部1 5以及模芯部1 6，受到射出時的壓力 再度後退至第1圖所示之位置。藉此，可動模具12之 動框部1 7相對於模芯部16位於前方，對於固定模具 之模穴形成面62和可動模具12之模穴形成面27之間 變寬後之模穴1 4，能進行熔融樹脂之射出。這時模穴 之板厚，相較於第2圖所示之合模力作用的位置，係加 最大爲50〜200μπι左右。 當藉由射出裝置使螺桿位置到達既定的保壓切換位 後，從射出控制切換成保壓控制。在進行保壓切換之前 或同時，將合模力減壓成20〜50kN。接著將可動模具 之模穴形成面27朝固定模具側移動，而對模穴1 4內的 融樹脂（從模穴形成面27、62側開始硬化）施以壓縮。相 於開模方向之移動量’是以1/3的移動量至同量的移動 來進行壓縮。在本實施形態’係藉由可動模具1 2之移 來對熔融樹脂施以壓縮，因此能比通常的射出成形進行 良好的凹槽及凸點之轉印。 在本實施形態，從開始開模前（排壓前），就將連通 空氣通路44、45、64之閥打開’從未圖示之壓縮空氣 應源對前述空氣通路44、45、64以及空氣通路3 0b、3 、32b、33b、64a、64b等等供應壓縮空氣。又當經過既 -20- 200827796 (18) 的合模時間後，從合模裝置進行排壓。經由排壓，使來自 各空氣通路64、64a、64b之空氣作用於導光板p和模穴 形成面之間，而促進導光板P相對於可動模具1 2之脫模 〇 之後，藉由合模裝置使可動盤及可動模具1 2朝開模 方向移動。這時在模穴14內所形成之導光板P，藉由前 述澆道襯套56內面之粗面加工及突出銷20之前端加工等 ，而使澆道部P2容易從澆道襯套56拔出，又將模具設計 成在澆道襯套56內不致發生澆道部P2之切斷。因此，即 使澆道部P2之澆口部P 1附近的冷卻媒體流路46或澆道 部P2附近之冷卻媒體流路63所流過的冷卻媒體溫度較高 溫，仍不致發生問題。又在可動模具12側，充滿於前述 空氣通路44、45之壓縮空氣，在打開模具後，係經由模 穴形成面30c、31c、32c、33c、33e和側面P9之間隙等 而噴向外部，以促進導光板P之脫模。又在進行開模之同 C 時或稍晚，對前述移動機構之汽缸35的桿部側室供應空 氣，使包含塊體43之第1框體部3 0向外側（第1圖至第3 圖中之上方）移動，而使其離開導光板P之包含光入射面 P3的部分。 然後用圖示之取出機的把持部把持澆道部P2，並作 動頂出用汽缸21而使突出銷20突出，將澆道部P2的背 面側向前頂，而使導光板P(包含澆口部P1及澆道部P2) 相對於可動模具1 2完全地脫模後取出，再移動至其他的 裝載位置。 -21 - 200827796 (19) 當從可動模具1 2取出導光板p後’進行下一個成形 ，本實施形態之成形循環時間僅4秒’比起習知之導光板 的成形循環時間須花費1 〇數秒’在時間上可大幅縮短。 其理由包括··對於固定模具1 3之模穴形成面62、澆道襯 套56、可動模具12之模穴形成面27、澆口部形成面39 分別藉由冷卻媒體來進行冷卻控制，以及藉由進行射出壓 縮成形來縮短保壓時間等等。又藉由1次成形1個之模具 來同時進行1片導光板P的成形，不須像藉由1次成形複 數個之模具來同時成形出複數片導光板時那樣還要考慮樹 脂之均一充塡等問題，僅須追求1片導光板之成形條件即 可，因此幾乎不會發生不良品。 在本實施形態，係以4秒的成形循環時間來成形出對 角尺寸2吋、板厚0.6mm之導光板P ;本發明，對於對角 尺寸1吋〜5吋（換算成面積包含75cm2以下者，也包含在 四隅沒有角部但在前述面積範圍內者）、板厚均一之 、 〇.25mm〜1.0mm的導光板P，能用2·5秒〜6秒的成形循 環時間進行成形。成形循環時間2·5秒中，如第7圖之小 型導光板之射出壓縮成形方法之流程圖所示，開閉模時間 (取出時間、中間時間及射出遲延時間（包含增壓時間 ))0.85秒，射出時間0.05秒，保壓時間0.4秒，冷卻時間 1 ·2秒。只要小型導光板的尺寸在此範圍內，就不會對成 形循環時間造成太大影響，但若進一步縮短成形循環時間 時，冷卻時間會不足，厚度最厚之澆道部Ρ2之硬化不足 ，這時無法拔取澆道部Ρ2而會發生澆道切斷。 -22- 200827796 (20) 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9圖所示之澆道部P2的直 徑及錐角（脫模傾斜角度）0。在本實施形態，射出裝置之 噴嘴之噴嘴孔（未圖示）的直徑爲1.5mm。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56的 噴嘴孔側的注入孔56a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10圖至第14圖係顯示出 ，使用能取出 2個導光板P(對角尺寸 2.8吋、板厚 0.4mm)之小型導光板P的射出壓縮成形模具進行測試的結 果，其測試條件爲：用來冷卻模穴形成面27、62之冷卻 媒體通路28、61的冷卻水溫度各90°C，噴嘴溫度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10圖係顯示，使用注入孔56a的直徑1.6mm、第9 圖中放大顯示之錐角0爲1°、長度25 mm的澆道襯套56 、 時之數據。在本例，當澆道襯套56之冷卻溫度爲70°C、 8 0 °C的情形，當成形循環時間變長（5秒以上）時澆道襯套 56之注入孔56a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等的問題。當澆道襯套 56的冷卻溫度爲90°C的情形，在6秒以上時也會發生不 良。因此，澆道襯套56之注入孔56a的直徑爲1.6mm時 ，其實用範圍變得極窄，當其數値更小時，將無法進行符 合實用之設定調整。 第1 1圖係顯示，使用注入孔56a的直徑2.0mm、第9 -23- 200827796 (21) 圖所示之錐角0爲1°、長度25 mm的澆道襯套56時之數 據。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、澆道切斷的情形 ，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40t的情形，由於成形品中 會混入冷料塊，故成形採用之冷卻溫度宜爲50°C以上。又 在1 20 °C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 〇 °C以下。 第12圖係顯示，使用注入孔56a的直徑2.3mm、第9 圖所示之錐角0爲1°、長度25 mm的澆道襯套56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80°C、90°C的情形， 在成形循環時間5秒時會發生澆道切斷。 第1 3圖係顯示，使用注入孔5 6 a的直徑2 · 6 m m、第9 圖所示之錐角0爲Γ、長度25mm的澆道襯套56時之數 據。在本例，由於流道連接部56c之直徑爲3.47mm，該 部分的冷卻硬化很耗時間。在本例，當冷卻溫度爲70 °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 °C的情形，在成形循環時間6秒時也會 發生繞道切斷。因此，當注入孔5 6 a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 -24- 200827796 (22) 說是上限的直徑。 第14圖係顯示，使用注入孔56a的直徑分 1.6mm、2.0mm、2.3mm、2.6mm，錐角 0 爲 1.5°、 25mm的澆道襯套56時，以冷卻溫度70°C進行測試 數據。在本例，流道連接部5 6c之直徑，分別對應於 注入孔尺寸而形成 2.9mm、3.3mm、3.6mm、3.9mm， 厚的部分之冷卻硬化特別會發生過慢的問題。在注 56a的直徑2.6mm、流道連接部64c直徑3.9mm、錐 爲1.5°的例子，在冷卻溫度70°C的情形，在成形循環 5秒時會發生澆道切斷，在6秒時會發生澆道之伸長 曲，因此判斷成不符實用。又關於其他注入孔5 6a之 尺寸，相較於澆道襯套56的內孔56b之錐角0爲厂 形，若不將最短的成形循環時間予以延長則會發生成 良。因此，在成形循環時間限定爲6秒以內的情形， 最慢的澆道襯套56(具有內孔56b)之流道連接部56c 徑3.6mm，乃實用範圍最大的直徑。 關於澆道襯套5 6的內孔5 6b之較佳錐角0，從 孔5 6a朝流道連接部56c宜以0· 5〜2.0°擴徑。然而， 道連接部56c的直徑超過3.6mm時，即使成形循環時 6秒（冷卻時間3.9秒），流道連接部56c附近之冷卻 仍過慢，在開模時可能會發生澆道部P2之切斷。一 道部P2在澆道襯套5 6內殘留時，除必須中斷連續成 業外，熟練的作業員必須在狹小空間內作業以取出澆 P2，如此可能造成模具損傷。在澆道襯套5 6的小徑 別爲 長度 時之 前述 此最 入孔 角0 時間 或彎 直徑 的情 形不 冷卻 的直 注入 當流 間爲 硬化 旦澆 形作 道部 部之 -25- 200827796 (23) 冷卻媒體流路6 3設置部分的壁厚5 6 d宜: 右。 又在本發明，如第8圖之流程圖所示 3吋、板厚0.6mm(均一板厚）之具有轉印 能以成形循環時間6.0秒進行射出壓縮成 時的冷卻時間爲3 · 9秒。所成形之導光板 大時成形循環時間有越長的傾向，但若更 時間，除伴隨經濟性的問題等外，當例如丨 ，也會發生噴嘴冷卻、加熱筒內之樹脂劣 在第8圖之小型導光板之射出壓縮成形方 和本實施形態相同之澆道襯套56。 所成形出的導光板Ρ，將澆口部Ρ 1 行精加工處理，作爲側光型導光板組裝於 施形態所成形出之導光板Ρ，澆口附近部 部Ρ12之板厚Ρ6差在ΙΟμχη以內而屬於良 板Ρ和光源之LED等組合後進行測試時 及將光出射面9等分時各部之平均亮度， 顯示良好的結果。 關於本發明，雖未逐一列舉，但並不 態，當然也包括熟習此技藝人士根據本發 改變。在本實施形態，雖是針對對角尺寸 用的導光板之射出壓縮成形模具作說明， 的小型導光板（1吋〜5吋，板厚0.2 5 m m〜 在本實施形態所說明的例子，係針對 爲 1 5〜3 0mm左 ，對於對角尺寸 圖案的導光板， 形而成形出，這 的面積、板厚越 加延長成形循環 g過9〜1 0秒時 化等的問題。又 法中，也是使用 的部分切斷後進 顯示裝置。本實 P 1 1和澆口遠方 品。將則述導尤 ，其均一度、以 均符合目標値而 限於上述實施形 明的要旨所做的 2吋之行動電話 但也能製造其他 1.0mm)。 能同時成形出1 -26- 200827796 (24) 片行動電話用導光板之射出壓縮成形模具（1次成形1片） 作說明，但也適用於例如同時成形出2片導光板的情形。 又在本實施形態，係針對在水平方向進行開閉模之射出壓 縮成形機上所裝設之射出壓縮成形模具作說明，但也能適 用於在垂直方向進行開閉模者。 本實施形態之導光板P，由於板厚〇. 6mm而採用射出 壓縮成形方法，但在板厚0.25〜0.5mm左右的情形，可使 用射出壓縮成形中之射出模壓方法。射出模壓方法，由於 在閉模位置其模穴之間隔寬廣，即使板厚極薄的情形仍能 以較低速低壓來進行射出，在射出後可動模具會前進而進 行壓縮。這時之合模速度宜爲高速。例如前述般導光板板 厚爲0.25〜0.5mm的情形，若在到達50%〜100%板厚之射 出前進一步加寬模穴之間隔，熔融樹脂之充塡變得更容易 且板厚變得更均一。又當板厚較薄時，可將澆口部加寬。 第1 5圖所示之小型導光板之射出模壓方法之流程圖，係 ( 以4.2秒的成形循環時間成形出對角尺寸3吋、板厚 0.3 mm(均一板厚）之具有轉印圖案的導光板。這時的冷卻 時間爲2.2秒。 又關於成形所使用之樹脂，雖僅記載聚碳酸酯（例如 出光興產之達夫隆LC 1 5 00)的例子，但只要光學性能優異 即可，例如可使用甲基丙烯酸樹脂、環烯烴聚合物樹脂等 等。甲基丙烯酸樹脂之玻璃轉化溫度爲90 °C，在使用甲基 丙烯酸樹脂時，冷卻媒體溫度宜爲40〜80 °C。由於依樹脂 的種類，熔融樹脂之溫度及玻璃轉化溫度會有不同，當然 -27- 200827796 (25) 冷卻媒體之溫度、成形循環時間等等也會有所不同。又本 發明之導光板之範圍，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圖係本實施形態之小型導光板之射出壓縮成形方 法所使用之射出壓縮成形模具之截面圖，其顯示合模力尙 未作用時的狀態。 第2圖係本實施形態之小型導光板之射出壓縮成形方 法所使用之射出壓縮成形模具之截面圖’其顯示合模力作 用後的狀態。 第3圖係顯示本實施形態之小型導光板之射出壓縮成 形方法所使用之射出壓縮成形模具之可動模具之前視圖。 第4圖係本實施形態之小型導光板之射出壓縮成形方 法所使用之射出壓縮成形模具之固定模具之前視圖° , 第5圖係本實施形態之小型導光板之射出壓縮成形方 法所成形出之小型導光板之立體圖° 第6圖係顯示本實施形態的小型導光板之射出壓縮成 形方法之流程圖。 — 第7圖係顯示其他實施形態的小型導光板之射出壓縮 成形方法之流程圖。 第8圖係顯示其他實施形態的小型導光板之射出壓縮 成形方法之流程圖。 第9圖係顯示本實施形態的小型導光板之射出壓縮成 -28- 200827796 (26) 形模具之澆道襯套之放大截面圖。 第1 〇圖係顯示本實施形態的小型導光板之射出壓縮 成形模具之澆道形狀和成形循環時間的關係。 第11圖係顯示本實施形態的小型導光板之射出壓縮 成形模具之澆道形狀和成形循環時間的關係。 第1 2圖係顯示本實施形態的小型導光板之射出壓縮 成形模具之澆道形狀和成形循環時間的關係。 第1 3圖係顯示本實施形態的小型導光板之射出壓縮 成形模具之澆道形狀和成形循環時間的關係。 第i4圖係顯示本實施形態的小型導光板之射出壓縮 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小型導光板之射出模 壓方法之流程圖。 【主要元件符號說明】 1 1 :射出壓縮成形模具 1 2 :可動模具 1 3 :固定模具 1 4 :模穴 1 5、5 1 :模具本體部 1 6 :模芯部 1 7 :可動框部 27、 30c、 31c、 32c、 33c、 62:模穴形成面 28、 46、61、63 :冷卻媒體流路 -29 - 200827796 (27) 3 0 :第1框體部 3 1 :第2框體部 3 2 :第3框體部 3 3 :第4框體部 30a、31a、32a、33a、43a、53a、55a:對向面 42 :光入射面形成面 43 :塊體 30b、 30d 、 31b、 31d、 32b、 32d、 33b、 33d、 44、 45、 64 、64a、64b:空氣通路 5 3 :第1抵接塊 54 :模穴形成塊 5 5 :第2抵接塊 56 :澆道襯套 P :導光板 P 3 :光入射面 P3a :凹槽 P8 :反射面 P 1 〇 :光出射面 -30-200827796 (1) EMBODIMENT OF THE INVENTION [Technical Field] The present invention relates to an injection compression molding method, an injection compression molding die, and a small light guide plate for a small light guide plate, and more particularly to an injection compression of a light guide plate for a mobile phone. A molding method, an injection compression molding die, and a small light guide plate. [Prior Art] A light guide plate used for a display device such as a liquid crystal, a plasma, or an organic EL is generally formed by injection molding or injection compression molding thereof. When the light guide plate is formed by injection compression molding, it is desirable to shorten the molding cycle time in order to improve the production efficiency. The forming cycle time of the light guide plate depends on its size and thickness. The light guide plate of 8 吋 and 12 mm thick of Patent Document 1 must have a molding cycle time of 1 60 seconds or longer. On the other hand, a small light guide for a mobile phone generally requires a forming cycle time of 1 〇 seconds. There is hardly any known document mentioning the forming cycle time of a small light guide plate, and only a few points are mentioned in Patent Document 2. Patent Document 2 is a light guide plate in which 1 to 8 inches is formed, and it is revealed that "the pressure holding is preferably applied by a pressure of about 2/3 to 1/3 of the peak pressure. 3~1. After 5 seconds, it is further applied with a lower pressure for a few seconds. Usually, in addition to the dwell time, it takes a longer cooling time, plus the injection time, the opening and closing time, the take-out time, etc., and the entire forming cycle time is supposed to be 1 〇 seconds. In particular, in the case of a small light guide plate, the concept of combining the mold structure and various cooling medium flow paths to cool each portion such as a runner has not been known. -4 - 200827796 (2) [Patent Document 1] Japanese Laid-Open Patent Publication No. 2005-349646 (paragraph [0027], Table 1) [Patent Document 2] Japanese Patent Laid-Open Publication No. 2004-161975 (paragraph (0130) to [0133] OBJECTS OF THE INVENTION The present invention has been made in view of the above problems, and an object thereof is to provide an injection compression molding method and an injection compression molding die, which can be shortened when a small light guide plate is formed by injection compression molding. Another object is to provide an injection compression molding method and an injection compression molding die for a small light guide plate, which can shorten the molding cycle time of a small light guide plate and form a light guide plate excellent in optical performance. Provided is an injection compression molding method for a small light guide plate, which can shorten the molding cycle time of the small light guide plate and improve the mold release property of the light guide plate with respect to the mold, and the injection compression molding method of the small light guide plate described in claim 1 of the present invention, The diagonal size is 1吋~5吋, and the thickness of the thickest part is 〇. 25mm ~1. An injection compression molding method for a small light guide plate of 0 mm or less, characterized in that a mold cavity having a variable volume and a plate thickness is formed by fixing a cavity forming surface of a mold and a cavity forming surface of a movable mold, and the mold of the fixed mold The hole forming surface and the cavity forming surface of the movable mold are cooled by the cooling medium flow path, and the transfer surface is formed on any one of the cavity forming faces; at least one of the runner bushing or the gate forming surface is by Forming a small light guide plate by using a cooling medium flow path different from the cooling medium flow path of the cavity forming surface; and using the cavity to form a small light guide plate with a cycle time of 1.5 to 6 seconds to 6 seconds. . The injection compression molding method of the small light guide plate according to the present invention has a diagonal size of 1 吋 5 5 吋 and a thickness of the thickest portion 0. 25mm~l. An injection compression molding method for a small light guide plate of 〇mm or less, forming a cavity having a variable volume and a plate thickness by fixing a cavity forming surface of the mold and a cavity forming surface of the movable mold, and forming a cavity forming surface of the fixed mold And the cavity forming surface of the movable mold is cooled by the cooling medium flow path, and one of the cavity forming faces has a transfer surface; at least one of the runner bushing or the gate forming surface is formed by the mold The cooling medium flow path of the hole forming surface is cooled by different cooling medium flow paths; the small light guide plate is formed by the molding cavity with a molding cycle time of 2 · 5 seconds to 6 seconds. Therefore, the molding cycle time can be greatly shortened. [Embodiment] An injection compression molding method for a small light guide plate of the present invention will be described with reference to Figs. 1 to 14 . Fig. 1 is a cross-sectional view showing an injection compression molding die used in the injection compression molding method of the small light guide plate of the embodiment, showing a state in which the mold clamping force 尙 is not applied. Fig. 2 is a cross-sectional view showing an injection compression molding die used in the injection compression molding method of the small light guide plate of the embodiment, showing a state in which the mold clamping force is applied. Fig. 3 is a front view showing a movable mold of an injection compression molding die used in the injection compression molding method of the small light guide plate of the embodiment. Fig. 4 is a front view showing a fixed mold for ejecting a compression molding die used in the injection compression molding method of the small light guide plate of the present embodiment. Fig. 5 is a perspective view of a small light guide plate formed by the injection compression molding method of the small light guide plate of the embodiment -6 - 200827796 (4). Fig. 6 through Fig. 8 are flowcharts showing an injection compression molding method of the small light guide plate of the embodiment. Fig. 9 is an enlarged cross-sectional view showing a sprue bush of a small-sized light guide plate of the present embodiment which is taken out of a compression molding die. Figs. 1 to 14 show the relationship between the runner shape and the molding cycle time of the injection compression molding die of the small light guide plate of the present embodiment. An injection compression molding machine (not shown) is provided with a heating cylinder (with a screw), an injection device for a nozzle, and a mold clamping device, and is disposed on a machine tool. The mold clamping device is provided between a fixed plate fixed to the machine tool (with a fixed mold 13) and a pressure plate disposed on the machine tool, and is provided with four tie bars. A movable disk equipped with a movable mold 12 is movably assembled to the aforementioned tie bar. A clamping cylinder (opening mold and clamping mechanism) for opening and closing the mold and clamping is disposed on the pressure plate, and the punching cylinder of the mold clamping cylinder is fixed to the back surface of the movable plate. In the mold clamping cylinder of the present embodiment, the pressure feed oil is sent to the assist cylinder (the cross-sectional area is small) by the control of the servo valve, so that the movable disk can be closed at a high speed. At the time of mold opening, the pressure feed oil is sent to the mold opening side oil chamber (small cross-sectional area) by the control of the servo valve, and the mold can be opened at a high speed. In this embodiment, the highest specification is that the mold can be opened on the mold closing side. The mold was opened and closed in 3 seconds. In the opening and closing mold and the mold clamping mechanism of the present embodiment, a mold clamping cylinder controlled by a servo valve is used. However, a toggle mechanism including a servo motor (which is excellent in starting rotation driving speed and stopping speed) and a ball screw can be used. At this time, the aforementioned speed can also be achieved. Further, with respect to the injection device, the injection speed can be between 100 mm/s and 400 mm/s, and can be emitted in 5 seconds. The injection molding die 11 of the small light guide plate of the present embodiment is used for the side light type of a mobile phone having a diagonal size of 2 吋 and a thickness of 〇 6 mm. 200827796 (5) Forming of a light guide plate. The injection compression molding can change the distance between the movable mold 1 2 and the fixed mold 13 during the start of the forming to the end of the forming. Therefore, in the form of "injection molding" in which the molten resin is injected at the closed position and the movable mold is advanced and compressed, the injection molding is also injection compression molding. In the injection compression molding, since the cavity is slightly opened before the start of injection or after the start of injection, it is not necessary to use an injection device having a high-speed injection capability, and can be ejected at a lower speed and a lower pressure. Molten resin. Since the molten resin can be ejected at a lower speed and a lower pressure, internal stress does not occur near the gate. Further, after the start of the injection, the movable mold is moved in the mold clamping direction to compress the molten resin. Therefore, the flow of the molten resin can be accelerated at a position far from the gate portion of the cavity, and the transfer of the fine pattern can be favorably performed. Further, since the mold clamping force is used to compress the molten resin in the cavity, the dwell time can be shortened, and the injection device can be transferred to the measuring step as soon as possible after the pressure is maintained, and the molding cycle time can be shortened. This injection compression molding is particularly suitable for forming a small light guide plate (hereinafter referred to as a light guide plate) having a thin plate thickness (compared to the area of a flat portion). Fig. 1 and Fig. 2 are cross-sectional views of the injection compression molding die 1 of the present invention, which are cross-sectional views taken along line A - A of Figs. 3 and 4, respectively. As shown in the above-mentioned first to fourth figures, the injection compression molding die 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 molds 1 2 after mold clamping. Between 1 and 3, a cavity 1 4 in which the volume and the thickness of the plate can be changed is formed. The mold main body portion 5, the core portion 16 and the movable frame portion 17 are attached to a movable mold 1 2 attached to a movable plate of an injection compression molding machine (not shown). A heat insulating plate 18 is attached to the movable disk side of the mold main body portion 15. The inside is equipped with a -8-200827796 (6). The ejector cylinder 2 1 is provided, and the protruding pin 20 can be moved back and forth through the ejector piece 19. . In the present embodiment, the bite portion 20a having a zigzag cross section is provided at the tip end of the protruding pin 20 so that the light guide plate P (including the gate portion P1 and the runner P2) can be easily held by the protruding pin 20. The jacking cylinder 21 is also actuated by a hydraulic cylinder or a servo motor. A recess 2 2 is formed in the lower four portions of the surface of the mold main body portion 15 on the fixed mold side, and the spring 2 3 is mounted in the recess 22 so as to face the fixed mold side. Further, the fixed mold side of the spring 23 abuts against the support plate 24 (constituting a part of the movable frame portion 17). Further, on the inner side of the concave portion 22 on the side surface of the fixed mold of the mold main body portion 15, guide holes 25 are formed in the upper and lower portions. The guide rod 26 provided from the support plate 24 toward the mold main body portion 15 is inserted into the above-described guide hole 25. Therefore, the movable frame portion 17 (including the support plate 24) disposed in parallel with the mold main body portion 15 is guided by the guide rod 26 and the guide hole 25, and the interval between the two is changed by the spring 32. k The core portion 16 is fixed substantially at the center of the side surface of the fixed mold of the mold main body portion 15. The core portion 16 of the present embodiment has a substantially square shape (having a chamfered portion and a convex portion) similar to the main portion P4 of the light guide plate p. The surface of the core portion 16 opposed to the fixed mold 丨3 is a surface forming surface of the light exit surface constituting the mirror surface forming surface 27 of the mirror surface. Inside the core portion 16, a plurality of cooling medium flow paths 28 which are parallel to the cavity forming surface 27 are formed. In the first and second figures, the core portion 1 is formed of an integral block, but the portion where the cavity forming surface is formed and other portions can be formed of independent blocks. Further, although the cavity forming surface 2 7 discloses an example of a mirror surface, it can also be constructed by performing groove or rough surface processing, etc. -9-200827796 (7). The frame portion 29 is disposed on the surface on the side of the fixed mold of the support plate 24 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 portion 17 (the support plate 24 and the frame portion 29). By the spring 23, the entire movable frame portion 17 can be moved in the opening and closing direction with respect to the mold main body portion 15 and the core portion 16. Fig. 1 shows the state in which the mold clamping force 尙 is not applied, the movable mold 1 2 when the spring 23 is extended, and Fig. 2 shows the state of the movable mold 12 after the spring 23 is contracted when the mold clamping force acts. As shown in Figs. 1 to 3, the frame portion 29 is composed of four frame portions 30, 3 1 , 3 2, and 3 3 . The first frame body portion 30 and the second frame body portion 3 1 are frames that move in a direction orthogonal to the opening and closing mold direction, and the third frame body portion 3 2 and the fourth frame body portion 3 3 are The frame that is fixed to the support board 24 cannot be moved. The moving mechanism of the first frame portion 30 located above the core portion 16 in Fig. 3 is on the upper surface of the support plate 24 so as to face the fixed mold side. The cylinder mounting portion 34 is protruded, and the cylinder portions of the two cylinders 35 are fixed to the upper surface of the cylinder mounting portion 34. Further, the rod portions of the respective cylinders 35 are placed downward through the respective holes of the cylinder mounting portion 34, and the respective rod portions are attached to the upper surface of the first frame portion 30. Therefore, the first frame body portion 30 is moved in the direction orthogonal to the opening and closing mold direction by the kinetic energy of the cylinder 35, that is, it can be retracted from the cavity forming position. In the moving mechanism of the second frame portion 31 on the right side of the core portion 16 in Fig. 3, the spring mounting portion 36 is protruded toward the fixed mold side on one side of the fixed mold side of the support plate 24. Inside the spring attachment portion 36, the recesses 3, 7 and 7 are formed on the side of the 10-200827796 (8) side, and the springs 38, 38 are attached to the recesses 37, 37 so as to face the second frame portion 31. The second frame body portion 31 is guided by a guide groove (not shown), and a part of the support plate 24 or the fourth frame body portion 33 constitutes a stopper on the forward side so that it is only in the left-right direction of FIG. Can move a little. The second frame body portion 3 1, is biased by the springs 38, 38 and continues to be in the cavity forming position. The reason why the second frame body portion 3 1 can be moved by a spring is to prevent the movable portion from being caught by the thermal expansion of the mold (particularly, the core portion 16) caused by the molten resin. The third frame portion 3 2 located on the left side of the core portion 16 in Fig. 3 is fixed to a position which is bilaterally symmetrical with the second frame portion 31. In the fourth frame portion 33 located below the core portion 16 in Fig. 3, a gate portion forming surface 39 which is continuous on the lower side of the center of the cavity forming surface 27 is formed. Further, a through hole 40 is formed in a central portion of the gate portion forming surface 39, and the protruding pin 20 for ejector is disposed so as to be movable forward and backward, and the protruding pin of the fourth frame portion 3 3 is further provided. Around the gate 20, a cooling medium flow path 46 is formed in the vicinity of the gate portion forming surface 39. As shown in FIG. 3, among the surfaces of the first frame body portion 30, the second frame body portion 3 1 , the third frame body portion 3 2 , and the fourth frame body portion 3 3 that face the fixed mold 13 , The opposing faces 30a, 31a, 32a, and 33a adjacent to the cavity 14 are processed to be more accurately processed than other portions in order to avoid generation of burrs and to form a small space through which air can flow when the cavity faces are formed by clamping. The flatness is higher. Further, air passages 30b, 3 1 b, and 3 2b are formed on the outer sides of the opposing faces 30 a, 3 1 a, 3 2 a, and 3 3 a so as to surround the cavity 14 and the independent block 43 to be described later. 3 3 b. The outer portion is formed to abut the surface of the fixed mold 13 to -11 - 200827796 Ο). Further, the first frame body portion 30, the second frame body portion 31, the third frame body portion 3, and the fourth frame body portion 3 3 are adjacent to the core portion 16 and are adjacent to the inner side surface of the mold opening and closing direction. The cavity forming faces 30c, 31c, 32c, 33c (for forming the side face P9 of the light guide plate P shown in Fig. 5) are formed. The cavity forming surface 33c includes a surface 3 3 e that forms the gate portion P 1 of the light guide plate P. The cavity forming faces 3 0 c, 3 1 c, 3 2 c, 3 3 c are connected to the inner side of the fixed disk side, and the outer faces of the core portions 16 are opposed to each other with a slight interval to avoid occurrence. Bite. In the cavity forming surface 30c of the first frame body portion 30, the light incident surface forming surface 42 for forming the light incident surface P3 of the light guide plate P is attached to the independent block 43 and the block is bolted. 43 is detachably attached to the other part of the first frame body portion 30. In the present embodiment, the member constituting the cavity of the mold is made of hard stainless steel and has a thermal conductivity of 20 to 24 W/(m • K). In the light guide plate P of the present embodiment, the light incident portion P 5 slightly protruding from the main portion P4 is formed at two places, and the end surface of the light incident portion P 5 is formed by forming a groove (longitudinal groove) P3a in the thickness direction. Light incident surface P3. In the present embodiment, the height difference (depth) between the apex and the valley portion of the groove P3a of the light incident surface P3 is 80 μm. Therefore, the block 43 which forms the light incident surface P3 has the light incident surface forming faces 42, 42 at two places (the grooves which are formed in parallel with the compression direction (opening and closing mold direction) of the cavity 14). Further, the length of the groove forming portion of the light incident surface forming surface 42 of the block 43 in the compression direction is the same as the thickness Ρ6 of the incident light surface Ρ3 of the light guide plate ρ. In other words, the portion -12-200827796 (10) exposed from the cavity forming surface 27 of the core portion 16 is formed into a groove only when the injection compression is completed. Further, when the injection compression is completed, the side faces of the core 邰 16 and the opposite sides of the side faces of the block 430 are formed by planes. The reason is that if the groove is formed on the side of the core portion 16 and the groove is engaged with the groove of the block 43, both of them must require high machining precision; and when the side of the block 43 is completely formed with grooves, the mold When the sides of the core portion 16 are all formed in a plane, burrs may occur in the gap formed between the groove and the plane. Further, in the present embodiment, the light incident surface forming surface 42 is formed of a groove, but may be selected from a bump, a surface on which a plurality of triangular pyramids or a quadrangular pyramid are formed, a rough surface subjected to sandblasting, a curved surface, or the like. A non-planar component other than a plane. As shown in Fig. 3, air passages 44, 45 are formed in the movable mold 12 to attract the air in the cavity 14 before the injection, and to blow the compressed air into the cavity 14 at the time of demolding including the discharge. . The air passages 44, 45 are connected to the vacuum device and the compressed air supply device via respective valve portions (not shown). The air passage 44 communicates with the air passage 30b formed on the opposite surface from the hole 44a of the first frame body portion 30. The air passage 30b communicates with the air passages 3 lb, 32b, 33b which are also formed on the opposite faces. Therefore, the compressed air of the air passages 30b, 31b, 32b, and 33b passes through the opposing faces 30a, 31a, 32a, 33a, and 43a and the opposing faces 53a and the facing faces 5 of the fixed mold 13 which will be described later. The gap formed by the 5 a or the like (the split surface) can be blown into the cavity 14 or sucked from the gap. Further, one of the compressed air portions is blown from the gap formed by the first frame body portion 30 and the block body 4 3 . The air passage 45 formed in the third frame portion 32 communicates with the air passage formed between the core portion 16 and each of the frame portions 30, 31, 3 2, and 3 3 - 200827796 (11) 30d, 31d, 32d, 33d. Therefore, the compressed air of the air passages 30d, 31d, 32d, and 3d passes through the outer side surface of the core portion 16 and the inner side surfaces of the frame portions 3 0 , 31 , 32 , 33 and the light incident surface of the block 43 . The gap formed by the formation surface 42 or the like can be blown into the cavity 14 or sucked from the gap. Therefore, the compressed air can be blown into the cavity 14 from the gap adjacent to the light incident surface forming surface 42. In the present embodiment, the first frame body portion 30 is designed to be retracted outward from the cavity forming position (the position in which the second frame body portion 13 is in contact with the second frame body portion 13 to form a continuous frame around the cavity 14). In order to easily facilitate the release of the light guide plate P from the movable mold 12, the light incident surface P3 of the light guide plate P is prevented from being damaged. In the present embodiment, only the block body 43 having the light incident surface forming surface 42 is detachably attached to the first frame body portion 30, and the block body 43 is replaced to reduce the cost. In the present embodiment, a so-called flat mold in which the frame portion 29 is movable in the mold opening and closing direction with respect to the core portion 16 is used. However, a so-called fitting mold, that is, a mold side mold ( The mold having the concave portion can be in the form of a mold core mold (a mold having a convex portion). Next, the fixed mold 13 will be described. As shown in FIG. 1, FIG. 2, and FIG. 4, the fixed mold 13 includes a mold main body portion 51, a cooling medium flow path forming block 52, a first abutting block 53, and a mold. The hole forming block 54, the second abutting block 55, the sprue bushing 56, and the like. A heat insulating plate 57 is attached to the fixed disk side of the mold main body portion 51, and a hole 58 for inserting an injection device nozzle (not shown) is formed at the center portion, and a positioning ring 59 is attached around the hole 58. Mounted on the movable mold side of the mold main body portion 51: the cooling medium flow path forming block 52 and the sprue bushing 56 are embedded in a block (second abutting block 55). A guide hole 60 through which the guide rod 41 of the movable mold 12 is inserted is provided in the mold main body portion 51. Fig. 9 is an enlarged cross-sectional view of the sprue bushing 56. The inner hole 56b of the sprue bushing 56 is tapered from the injection hole 56a on the nozzle abutting side toward the flow path connecting portion 56c (connected to the flow path portion). Expand the diameter. In the present embodiment, the taper angle (release angle) 0 with respect to the center line L represented by the one-dot chain line is Γ. The cooling medium flow path forming block 52 is formed with a plurality of cooling medium flow paths 61 in a manner parallel to the cavity 14 . The first abutting block 53 is fixed to the movable mold side of the cooling medium flow path forming block 52, and has a facing surface 53a opposed to the first frame portion 30 of the movable mold 12. Further, on the movable mold side of the cooling medium flow path forming block 52 and inside the first abutting block 53, the cavity forming block 54 is fixed by detachment. The surface of the cavity forming block 54 opposed to the movable mold 12 constitutes a cavity forming surface 62 (a reflecting surface (back surface) P8 for forming the light guiding plate P). In the present embodiment, the cavity forming surface 62 is formed. Fine concavo-convex processing is applied to the upper surface. Specifically, it is processed by sand blasting, and the closer to the block 43 side (upper side) of the fixed mold 13, the more unevenness is formed, that is, on the reflecting surface P8, the closer to the light incident surface P3 side, the higher density is formed. Fine bumps. Further, with respect to the cavity forming face 62, a groove can be formed to form a mirror surface. The reason why the detachable block is used as the cavity forming face 62 is that, similarly to the block 43 of the incident face forming face 42, the die forming face 62 can be replaced by the cavity forming block 54. Wear or test the shape of the reflective surface of various light guide plates P. Further, at least one of the cavity forming surface 6 of the fixed mold 13 and the cavity forming surface 27 of the movable mold 12 may be attached to the stamper. It is also possible to form a light exit surface or a reflection surface by forming one of the surfaces 27 and 62 by cavity formation -15-200827796 (13). The opposing surface 55a of the second abutting block 55 and the opposing surface 5 3 a of the first abutting block 53 are the first housing portion 30 and the second housing portion 3 1 of the movable mold 2 The third frame portion 32 and the fourth frame portion 33 are opposed to each other. A cylindrical sprue bushing 56 is disposed inside the second abutting block 55. The side of the fixed disk of the sprue bushing 56 faces the hole 5 of the mold main body portion 51, and the movable mold side faces the protruding pin 20. Between the sprue bushing 56 and the second abutting block 55 on the outer peripheral side thereof, the cooling medium flow path 63 around the sprue bushing 56 for cooling the sprue portion P2 is cooled by the cooling medium flow. Road 6 1 is controlled by a different system, the sides of which are sealed by a 0-ring to form a cold runner (including runner). Further, the inner peripheral surface of the sprue bushing 56 is subjected to rough surface processing by sand blasting to facilitate the demolding of the runner P2. Although the gate portion forming surface of the fixed mold 13 can be cooled by another cooling medium flow path, it is preferable to provide the cooling medium flow path 63 around the sprue bushing 56. Further, an air passage 64 is formed in the cavity forming block 54 to attract the air in the cavity 14 before the ejection, and to blow the compressed air at the time of demolding (including when the pressure is discharged). The air passage 64 is connected to the vacuum suction device and the compressed air supply device via valves (not shown). The air passage 64 communicates with the air passage 64a (formed between the cavity forming block 54 and the first abutting block 53) and the air passage 64b (formed between the cavity forming block 54 and the second abutting block 55) . The compressed air is blown into the cavity 14 from the gap between the cavity forming block 54 and the first abutting block 53 and the second abutting block 55 via the air passages 64a and 64b, and is sucked into the cavity 14 before being ejected. air. By forming the outer edge of the cavity -16 - 200827796 (14) forming block 5 4 to be smaller than the outer shape of the light guide plate P, more compressed air can be blown to the cavity forming surface 62 of the transfer surface. Next, an injection compression molding method using the injection compression molding die 1 of the present embodiment will be described. As described above, the present invention can be realized by a general injection molding method, but an injection compression molding method is preferred. As shown in Fig. 6, in the present embodiment, a diagonal dimension of 2 吋 and a plate thickness of 0 are formed by a molding cycle time of 4 seconds. 6mm light guide plate. Among them, the opening and closing mode time (including the take-out time, the intermediate time) 1_3 5 seconds, the injection time 0. 05 seconds, holding time 0. 4 seconds, cooling time 2. 2 seconds (substantially cooling is done from the beginning of the shot). Therefore, in the present embodiment, cooling of the cooling medium flow path 46 and the fixed mold 13 in the vicinity of the cooling medium flow path 28, the protruding pin 20, and the gate portion forming surface 39 of the core portion 16 of the movable mold 1 2 The cooling medium flow path 61 of the media flow path forming block 52 and the cooling medium flow path 63 in the vicinity of the sprue bushing 56 flow through a cooling medium (cooling water) controlled by a temperature regulator to 100 °C. Further, the temperature of the cooling water is preferably 50 to 110 ° C, preferably 40 to 100 ° C lower than the glass transition temperature Tg (145 ° C to 150 ° C) of the polycarbonate of the molding resin. That is, as shown in Fig. 1, when the temperature of the cooling water flowing through the cooling medium flow path 63 of the sprue bushing 56 is 40 ° C, the sprue bushing 56 is excessive in the molding cycle time of 7 seconds or longer. The problem of mixing the cold block in the molded article occurs by cooling. Further, when the temperature difference between the cavity forming blocks 54 of the fixed mold 13 is too large, in addition to the problem of poor thermal expansion, there is a problem in transfer, and therefore it is not suitable to form at 40 ° C or lower. Further, when the temperature of the cooling water flowing through the cooling medium flow path 63 is 1200 ° C, sprue cutting occurs in the case of the forming cycle time of 4 seconds, -17-200827796 (15), actually at this temperature, Since the sprue cutoff may occur, it makes no sense to form at this temperature. Further, in the conventional light guide plate forming mold, cooling is not performed in the vicinity of the gate P1 or in the vicinity of the runner P2. However, in the present embodiment, the gate portion P2 and the runner portion P2 are cooled at substantially the same temperature as the cavity forming surfaces 27 and 62. Further, in the present invention, the gate portion P1 and the runner portion P2 have a temperature difference of -60 ° C to +20 ° C with respect to the cavity forming faces 27 and 62 to ensure the fluidity of the molten resin at the time of injection, and The plate thickness difference between the gate P1 1 of the light guide plate P and the gate distal portion P 1 2 is reduced, and the molding cycle time is shortened. When the cooling temperature of the gate P1 is lower than the cooling temperature of the cavity forming faces 27, 62 by more than -60 ° C, the flow of the resin at the time of ejection deteriorates, which hinders the injection of the cavity 14 . As described above, the thickness of the plate P 1 1 in the vicinity of the gate portion of the light guide plate p and the gate distal portion P 1 2 are different. With respect to the cooling temperature of the cavity forming surface, when the cooling temperature of the gate portion forming surface 39 and the sprue bushing 56 exceeds +20 ° C, the cooling hardening % of the runner portion P2 becomes slow, when the movable mold 12 performs When the sprue portion P2 is pulled out from the sprue bushing 56 after the mold opening, the sprue portion P2 may be cut off, resulting in an increase in the forming cycle time. Further, the cooling temperature of the gate portion forming surface 39 and the sprue bushing 56 is preferably lower than the cooling temperature of the cavity forming surface. In the present invention, in addition to the cavity forming faces 27, 62, at least one of the sprue bushing 56 of the fixed mold 13 and the gate portion forming surface 39 of the movable die 12 is formed by the cooling medium flow path 28, 6 1 The cooling medium flow path 63' 46 of the different systems is cooled to ensure the resin flowability of the gate portion P1. However, when the runner bushing and the gate portion forming surface are not provided with a separate cooling medium flow path, the same as the case where the gate -18-200827796 (16) portion forming surface and the sprue bushing have a too high cooling temperature. This will cause the molding cycle time to be prolonged; and when the cooling temperature of the entire mold is lowered, the transfer of the cavity forming surface will be insufficient. Further, the temperature of the cooling medium flow path of the fixed mold 13 and the cooling medium flow path 28 of the movable mold 12 may be changed to adjust the bending and birefringence of the light guide plate P and the like. Further, it is also possible to provide a gate cutter which can move forward and backward in the movable mold, and perform gate cutting before the mold opening to separate the small light guide plate P from the gate portion P1. Further, the temperature in the front region (the region closest to the nozzle) of the injection device was set to 310 ° C, and the measurement of the molten resin of the polycarbonate was carried out. In the case of using polycarbonate, the temperature of the front portion of the injection device is preferably set to be 300 to 3 80 °C. Then, the mold clamping device (not shown) is actuated to bring the movable mold 12 (the state shown in Fig. 1) attached to the movable disk into contact with the fixed mold 13 attached to the fixed disk. At this time, the frame-shaped portion formed by the first abutting block 53 and the second abutting block 55 of the fixed mold 13 is the first frame portion 30 and the second frame portion 31 of the movable mold 12. The frame body portion 29 composed of the third frame body portion 3 and the fourth frame body portion 33 is in contact with each other, and a cavity 14 including a gate portion forming surface 39 (connected to the runner portion 2) is formed therein. Upon formation of the cavity 14, the valve is opened to communicate the air passages 44, 45, 64 to the vacuum suction means and to attract air within the cavity 14. Further, in the present embodiment, in order to shorten the molding cycle time, the nozzle of the injection device (not shown) is continuously abutted against the sprue bushing 56. The mold clamping force before the start of the injection after the mold is abutted must be the mold force that abuts the mold main body portion 15 of the movable mold 12 and the support plate 24 of the movable frame portion 17 against the elastic pressure of the spring 23, in this embodiment. The form is 5 〇 -19- 200827796 (17) The part can be 13 隔 14 宽 宽 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 As shown in Fig. 2, the support plate 24 is brought into contact with the mold body 15 at this time, and the frame portion 29 is positioned at the final retracted position with respect to the core portion 16 and then passed through the sprue bushing from the nozzle of the injection device (not shown). 5 6 The molten resin was injected at an injection speed of 100 00 mm/SeC. The mold main body portion 15 and the core portion 16 of the movable plate and the movable mold 12 are again retracted to the position shown in Fig. 1 by the pressure at the time of injection. Thereby, the movable frame portion 17 of the movable mold 12 is positioned forward with respect to the core portion 16, and the cavity 14 is widened between the cavity forming surface 62 of the fixed mold and the cavity forming surface 27 of the movable mold 12. It is possible to eject the molten resin. At this time, the thickness of the cavity is increased by about 50 to 200 μm compared to the position at which the mold clamping force shown in Fig. 2 is applied. When the screw position reaches the predetermined pressure holding switching position by the injection device, the injection control is switched to the pressure holding control. The mold clamping force is reduced to 20 to 50 kN before or at the same time as the pressure holding switch is performed. Next, the cavity forming surface 27 of the movable mold is moved toward the fixed mold side, and the molten resin in the cavity 14 (hardened from the side of the cavity forming faces 27, 62) is compressed. The amount of movement ' with respect to the mold opening direction is compressed by a movement of 1/3 to the same amount. In the present embodiment, the molten resin is compressed by the movement of the movable mold 12, so that the grooves and the bumps can be transferred better than the usual injection molding. In the present embodiment, the valve connecting the air passages 44, 45, and 64 is opened before the start of the mold opening (before the pressure discharge). The compressed air from the unillustrated source is supplied to the air passages 44, 45, 64 and the air. The passages 3 0b, 3, 32b, 33b, 64a, 64b, etc. supply compressed air. After passing the clamping time of -20-200827796 (18), the pressure is released from the mold clamping device. The air from each of the air passages 64, 64a, 64b acts between the light guide plate p and the cavity forming surface via the pressure discharge, and facilitates the mold release of the light guide plate P with respect to the movable mold 1 2 by clamping The device moves the movable plate and the movable mold 12 in the mold opening direction. At this time, the light guide plate P formed in the cavity 14 is easily cut from the sprue bushing 56 by the rough surface processing of the inner surface of the sprue bushing 56 and the front end processing of the protruding pin 20. Further, the mold is designed such that the sprue portion P2 is not cut in the sprue bushing 56. Therefore, even if the temperature of the cooling medium flowing through the cooling medium flow path 46 in the vicinity of the gate portion P1 of the runner portion P2 or the cooling medium flow path 63 in the vicinity of the runner portion P2 is relatively high, no problem occurs. Further, on the side of the movable mold 12, the compressed air filled in the air passages 44 and 45 is sprayed to the outside through the gap between the cavity forming surfaces 30c, 31c, 32c, 33c, and 33e and the side surface P9 after the mold is opened. To promote the release of the light guide plate P. Further, when the mold is opened at the same time C or later, air is supplied to the rod side chamber of the cylinder 35 of the moving mechanism, and the first frame portion 30 including the block 43 is outward (Fig. 1 to Fig. 3). Moving upward, leaving it away from the portion of the light guide plate P that includes the light incident surface P3. Then, the runner portion P2 is gripped by the grip portion of the unloader shown in the drawing, and the ejector cylinder 21 is actuated to project the projecting pin 20, and the back side of the runner portion P2 is pushed forward to allow the light guide plate P to be poured. The mouth portion P1 and the runner portion P2) are completely released from the movable mold 1 2, taken out, and moved to another loading position. -21 - 200827796 (19) When the light guide plate p is taken out from the movable mold 1 2, the next molding is performed, and the molding cycle time of the present embodiment is only 4 seconds. It takes 1 〇 seconds compared to the conventional molding cycle time of the light guide plate. 'In terms of time, it can be greatly shortened. The reason for this includes that the cavity forming surface 62 of the fixed mold 13 , the sprue bushing 56 , the cavity forming surface 27 of the movable mold 12 , and the gate forming surface 39 are respectively cooled by a cooling medium, and The pressure holding time and the like are shortened by performing injection compression molding. Further, by molding one mold once in a single pass, one sheet of the light guide plate P is simultaneously formed, and it is not necessary to consider the uniform charge of the resin as in the case of forming a plurality of light guide plates simultaneously by forming a plurality of molds one time. For example, it is only necessary to pursue the molding conditions of one light guide plate, so that defective products hardly occur. In the present embodiment, the diagonal dimension is 2 吋 and the plate thickness is 0. 6mm light guide plate P; the present invention, for a diagonal size of 1 吋 to 5 吋 (converted to an area including 75 cm 2 or less, also included in the four ridges without a corner but within the aforementioned area), uniform thickness, 〇. 25mm~1. The 0 mm light guide plate P can be formed by a forming cycle time of 2.5 seconds to 6 seconds. In the forming cycle time of 2.5 seconds, as shown in the flow chart of the injection compression molding method of the small light guide plate of Fig. 7, the opening and closing mode time (the take-out time, the intermediate time, and the injection delay time (including the pressurization time)) is 0. 85 seconds, shooting time 0. 05 seconds, holding time 0. 4 seconds, cooling time 1 · 2 seconds. As long as the size of the small light guide plate is within this range, the molding cycle time will not be greatly affected. However, if the molding cycle time is further shortened, the cooling time will be insufficient, and the thickest runner portion 2 will be insufficiently hardened. If the sprue section 2 cannot be removed, the sprue cutoff will occur. -22- 200827796 (20) As described above, the most influential factor determining the cooling time in the molding cycle time of the present invention is the diameter and taper angle of the runner portion P2 as shown in Fig. 9 (released) Tilt angle) 0. In the present embodiment, the diameter of the nozzle hole (not shown) of the nozzle of the injection device is 1. 5mm. When the sprue is demolded, in order to remove the resin at the tip end of the nozzle well, the diameter of the injection hole 56a on the nozzle hole side of the sprue bushing 56 must be larger than the diameter of the nozzle hole, and it is preferable to form 1. Injection hole of 6mm or more. Figures 10 to 14 show that the use of two light guide plates P can be taken out (diagonal size 2. 8吋, plate thickness 0. The test results of the injection compression molding die of the small light guide plate P of 4 mm) were tested under the following conditions: the cooling water temperature of the cooling medium passages 28, 61 for cooling the cavity forming faces 27, 62 was 90 ° C each, and the nozzle temperature 3 25 °C, the front temperature of the heating cylinder is 3 5 5 °C, the middle temperature of the heating cylinder is 3 70 °C, the temperature of the rear part of the heating cylinder is 3 60 °C, and the injection speed is 300 mm/sec. Figure 10 shows the diameter of the injection hole 56a using 1. In the 6mm and ninth figures, the data of the sprue bushing 56 with a taper angle 0 of 1° and a length of 25 mm is shown. In this example, when the cooling temperature of the sprue bushing 56 is 70 ° C or 80 ° C, the injection hole 56a of the sprue bushing 56 and the nozzle of the nozzle are formed when the forming cycle time becomes longer (5 seconds or more). When the pores are excessively cooled, there is a problem in that the next shot cannot be performed, and the cold block is mixed in the molded article. When the cooling temperature of the sprue bushing 56 is 90 ° C, defects may occur even when it is 6 seconds or longer. Therefore, the diameter of the injection hole 56a of the sprue bushing 56 is 1. At 6mm, the practical range becomes extremely narrow, and when the number is smaller, it will not be able to perform practical setting adjustments. Figure 11 shows the diameter of the injection hole 56a. 0mm, 9th -23-200827796 (21) The data shown in the figure is 0 when the taper angle 0 is 1° and the length is 25 mm. 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 runner may be cut, but the 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 40 t, since the cold block is mixed in the molded article, the cooling temperature for forming is preferably 50 ° C or higher. Also, at 10 ° C, the runner is cut off at 4 seconds, so the cooling temperature for forming is preferably 1 1 〇 ° C or less. Figure 12 shows the diameter of the injection hole 56a. The data of the runner bushing 56 having a cone angle 0 of 1° and a length of 25 mm shown in Fig. 9 is shown in Fig. 9. In this case, when the cooling temperature is 70 °C, sprue cutting occurs at a molding cycle time of 3 seconds, and occurs at a cooling temperature of 80 ° C and 90 ° C at a molding cycle time of 5 seconds. The sprue is cut. Fig. 13 shows the data obtained when the diameter of the injection hole 5 6 a is 2 · 6 m m and the taper angle 0 shown in Fig. 9 is the sprue bushing 56 of Γ and length 25 mm. In this example, the diameter of the flow path connecting portion 56c is 3. 47mm, this part of the cooling hardening is time consuming. In this case, when the cooling temperature is 70 °C, sprue cutting and wire drawing occur at a molding cycle time of 5 seconds, at a cooling temperature of 80 ° C, 90 ° C, and a forming cycle time of 6 seconds. A bypass cut will also occur. Therefore, when the diameter of the injection hole 5 6 a is 2. In the case of 6 mm, in order to achieve the ideal forming cycle time within 6 seconds, it can be -24-200827796 (22) is the upper limit diameter. Figure 14 shows the diameter of the injection hole 56a. 6mm, 2. 0mm, 2. 3mm, 2. 6mm, cone angle 0 is 1. When the sprue bushing 56 of 5° and 25 mm was used, the test data was carried out at a cooling temperature of 70 °C. In this example, the diameters of the flow path connecting portions 56c are respectively formed corresponding to the size of the injection holes. 9mm, 3. 3mm, 3. 6mm, 3. 9mm, the thickening of the hardening of the thick part is particularly slow. In the diameter of note 56a 2. 6mm, the runner connection portion 64c has a diameter of 3. 9mm, cone is 1. In the case of 5°, in the case where the cooling temperature is 70 ° C, the runner is cut off at the time of the molding cycle for 5 seconds, and the run length of the runner occurs at 6 seconds, so that it is judged to be inconsistent with practical use. Further, regarding the size of the other injection hole 516a, the taper angle 0 of the inner hole 56b of the sprue bushing 56 is a factory shape, and it is improved if the shortest molding cycle time is not extended. Therefore, in the case where the molding cycle time is limited to 6 seconds, the runner connection 56c having the slowest sprue bushing 56 (having the inner hole 56b) has a diameter of 3. 6mm, the largest diameter in the practical range. The preferred taper angle 0 of the inner hole 5 6b of the sprue bushing 56 is preferably 0·5~2 from the hole 5 6a toward the flow path connecting portion 56c. 0° expansion. However, the diameter of the land connecting portion 56c exceeds 3. At 6mm, even for 6 seconds during the forming cycle (cooling time 3. 9 seconds), the cooling in the vicinity of the flow path connecting portion 56c is still too slow, and the sprue portion P2 may be cut off during mold opening. When the P2 remains in the sprue bushing 56, in addition to having to interrupt the continuous manufacturing, the skilled worker must work in a small space to take out the pour P2, which may cause mold damage. When the small diameter of the sprue bushing 56 is not the length, the above-mentioned maximum inlet angle 0 time or the curved diameter is not cooled, and the direct injection is between the flow and the hardening is performed. -25-2727796 (23) The wall thickness of the cooling medium flow path 6 3 is set to 5 6 d: right. In the present invention, as shown in the flowchart of FIG. 3, the thickness is 0. 6mm (uniform plate thickness) has a transfer energy with a forming cycle time of 6. The cooling time for injection compression at 0 seconds is 3 · 9 seconds. When the formed light guide plate is large, the molding cycle time tends to be longer. However, if it is more time-consuming, in addition to economical problems, for example, the nozzle may be cooled, and the resin in the heating cylinder may be inferior in the eighth drawing. The small light guide plate is injection-molded and formed into a sprue bushing 56 of the same embodiment. The formed light guide plate 精 is finished by finishing the gate portion Ρ, and is assembled as a side light type light guide plate in the light guide plate 成形 formed by the application form, and the thickness Ρ6 of the portion Ρ12 near the gate is ΙΟμχη The average brightness of each part when the test was performed after combining the LEDs of the good board and the light source, and the light exit surface 9 was equally divided, and showed good results. The present invention has not been enumerated one by one, but it is not a matter of course, and it is of course also included by those skilled in the art in accordance with the present invention. In the present embodiment, a small light guide plate (1 吋 to 5 吋, plate thickness 0.) for explaining the injection compression molding die of the light guide plate for the diagonal size is described. 2 5 mm〜 In the example described in the present embodiment, the light guide plate having a diagonal size pattern is formed in a shape of 15 to 30 mm left, and the area and the thickness of the sheet are increased. 9~1 0 second time and other issues. In addition, the method is also used to cut off the rear display device. The real P 1 1 and the gate far away. It will be described as a mobile phone that is uniform and consistent with the goal and is limited to the gist of the above-mentioned implementation. However, it can also manufacture other 1. 0mm). It is possible to simultaneously form an injection compression molding die (one piece for one molding) of a light guide plate for a mobile phone of 1 -26-200827796 (24), but it is also applicable to, for example, a case where two light guide plates are simultaneously formed. Further, in the present embodiment, the injection compression molding die mounted on the injection compression molding machine that opens and closes the mold in the horizontal direction will be described. However, the present invention can also be applied to the opening and closing of the mold in the vertical direction. The light guide plate P of this embodiment has a thick plate thickness. 6mm and injection compression molding method, but the thickness is 0. 25~0. In the case of about 5 mm, the injection molding method in injection compression molding can be used. According to the injection molding method, since the interval of the cavity is wide at the closed position, even if the thickness is extremely thin, the injection can be performed at a lower speed and a lower pressure, and the movable mold advances and compresses after the injection. At this time, the clamping speed should be high speed. For example, the thickness of the light guide plate is 0. 25~0. In the case of 5 mm, if the interval between the cavities is further widened before reaching the 50% to 100% plate thickness, the filling of the molten resin becomes easier and the plate thickness becomes more uniform. When the thickness of the plate is thin, the gate portion can be widened. A flow chart of the injection molding method of the small light guide plate shown in Fig. 5 is (4. The forming cycle time of 2 seconds formed a diagonal size of 3 吋 and a plate thickness of 0. 3 mm (uniform plate thickness) light guide plate with transfer pattern. The cooling time at this time is 2. 2 seconds. Further, although the resin used for the molding is only an example of a polycarbonate (for example, Duffon LC 1 500), it is preferable that the resin is excellent in optical performance, and for example, a methacrylic resin or a cycloolefin polymer can be used. Resin and so on. The glass transition temperature of the methacrylic resin is 90 ° C, and when the methacrylic resin is used, the cooling medium temperature is preferably 40 to 80 °C. The temperature of the molten resin and the glass transition temperature vary depending on the type of resin. Of course, the temperature of the cooling medium, the molding cycle time, and the like may vary. Further, the range of the light guide plate of the present invention includes a light-transmitting resin plate such as a light diffusing plate. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a cross-sectional view showing an injection compression molding die used in the injection compression molding method of the small light guide plate of the embodiment, showing a state in which the mold clamping force 尙 is not applied. Fig. 2 is a cross-sectional view showing an injection compression molding die used in the injection compression molding method of the small light guide plate of the embodiment, showing a state after the mold clamping force is applied. Fig. 3 is a front view showing a movable mold of an injection compression molding die used in the method of injection compression molding of the small light guide plate of the embodiment. Fig. 4 is a front view of a fixed mold for injection compression molding die used in the injection compression molding method of the small light guide plate of the embodiment. Fig. 5 is a view showing the injection compression molding method of the small light guide plate of the embodiment. Stereoscopic view of a small light guide plate Fig. 6 is a flow chart showing a method of injection compression molding of the small light guide plate of the present embodiment. — Fig. 7 is a flow chart showing a method of injection compression molding of a small light guide plate of another embodiment. Fig. 8 is a flow chart showing an injection compression molding method of a small light guide plate of another embodiment. Fig. 9 is an enlarged cross-sectional view showing the sprue bush of the small-sized light guide plate of the present embodiment which is compressed and compressed into a -28-200827796 (26) mold. Fig. 1 is a view showing the relationship between the shape of the runner of the injection-molding mold of the small-sized light guide plate of the present embodiment and the molding cycle time. Fig. 11 is a view showing the relationship between the runner shape of the injection compression molding die of the small light guide plate of the present embodiment and the molding cycle time. Fig. 1 is a view showing the relationship between the runner shape of the injection compression molding die of the small light guide plate of the present embodiment and the molding cycle time. Fig. 13 is a view showing the relationship between the runner shape of the injection compression molding die of the small light guide plate of the present embodiment and the molding cycle time. Fig. i4 is a view showing the relationship between the runner shape and the molding cycle time of the injection compression molding die of the small light guide plate of the embodiment. Fig. 15 is a flow chart showing a method of injection molding of a small light guide plate of another embodiment. [Explanation of main component symbols] 1 1 : Injection compression molding die 1 2 : Movable die 1 3 : Fixed die 1 4 : Mold hole 1 5, 5 1 : Mold main body portion 1 6 : Core portion 1 7 : movable frame portion 27 , 30c, 31c, 32c, 33c, 62: cavity forming faces 28, 46, 61, 63: cooling medium flow path -29 - 200827796 (27) 3 0 : first frame body 3 1 : second frame body 3 2 : third frame body portion 3 3 : fourth frame body portions 30 a , 31 a , 32 a , 33 a , 43 a , 53 a , 55 a : opposite surface 42 : light incident surface forming surface 43 : blocks 30 b , 30 d , 31 b , 31d, 32b, 32d, 33b, 33d, 44, 45, 64, 64a, 64b: air passage 5 3 : first abutment block 54 : cavity forming block 5 5 : second abutment block 56 : sprue bushing P: light guide plate P 3 : light incident surface P3a: groove P8: reflective surface P 1 〇: light exit surface -30-