200935090 六、發明說明： 【發明所屬之技術領域】 本發明是有關於一種顯示系統，且特別是有關於一種 可消除鬼影之顯示系統。 【先前技術】 為了提高汽車駕駛者的行車安全，已經有汽車設計成 可以將車速或馬達轉速等行車資訊投射於擋風玻璃上，以 顯示給駕歇者。然而’現今之技術中，不管是以虛像成像 〇的方式，或是實像成像的方式，往往都會面臨到影像有鬼 影產生的問題，而造成駕駛者無法很清楚地辨識擔風玻璃 上所顯示的行車資訊。 目前已經有多種消除鬼影的技術被提出來。於美國專 利案號5,999,314中，係揭露了於擋風玻璃中間放置二分 之一波板，以消除鬼影的作法。此作法必須額外置入一片 布魯斯特(Brewster)膜以滿足亮度低損失的目的，而且必須 對擋風玻璃進行特殊之加工處理。 © 此外’於美國專利案號5,212,471揭露一種於擋風玻 璃中插入一片二分之一波板的作法。 而於美國專利案號7，123,418中提到一種於擋風玻璃 中放入反射式偏光片的作法。此反射式偏光片會阻隔從外 界進入的光線，而使得駕馱者無法看透（see through)反射 式偏光>1後方之景物。 【發明内容】 本發明提出一種顯示系統，包括一影像裝置、一透光 基板、及一位相差板。影像裝置用以產生一偏振影像光。 TW4268PA-C2 1 200935090 透光基板具有相對之一第一表面及一第二表面。位相差板 配置於透光基板之第一表面上。其中，部份之偏振影像光 經位相差板反射之後，係朝向一觀測方向射出，而其他部 份之偏振影像光穿透位相差板後，係大部分地由第二表面 射出。 本發明提出一種顯示系統，包括一影像裝置、一影像 反射元件及一偏光元件。影像裝置用以產生一偏振影像 光。影像反射元件包括一基板及一相位調變元件。相位調 變元件鄰接基板，相位調變元件具有一反射表面，用以接 收偏振影像光。其中當偏振影像光射向反射表面後，反射 表面反射部分之偏振影像光以產生一第一反射偏振影像 光，部分之偏振影像光射入相位調變元件，並由基板反射 後由反射表面射出，以產生一第二反射偏振影像光。第一 反射偏振影像光與第二反射偏振影像光之相位差實質上 為ηττ，η為正奇數。偏光元件用以接收並使第一反射偏 振影像光通過，且遮擔第二反射偏振影像光。 本發明提出一種顯示系統，包括一影像裝置、一透光 基板及一相位調變元件。影像裝置用以產生一偏振影像 光。相位調變元件鄰接透光基板，相位調變元件具有一反 射表面，用以接收偏振影像光。其中當偏振影像光射向反 射表面後’反射表面反射部分之偏振影像光以產生一反射 偏振影像光’部分之偏振影像光射入相位調變元件後成為 一入射偏振影像光《入射偏振影像光具有一所欲之偏振方 向’使得大部分之入射偏振影像光係穿透透光基板。 TW4268PA-C2 4 200935090 為讓本發明之上述内容能更明顯易懂，下文特舉較佳 實施例，並配合所附圖式，作詳細說明如下： 【實施方式】 本發明係揭露一種顯示系統，包括一影像裝置、一透 光基板、及一位相差板。影像裝置用以產生一偏振影像 光。透光基板具有相對之一第一表面及一第二表面。位相 差板配置於透光基板之第一表面上。其中，部份之偏振影 像光經位相差板反射之後，係朝向一觀測方向射出，而其 〇他部份之偏振影像光穿透位相差板後，係大部分地由第二 表面射出。 實施例一 請參照第1圖，其繪示乃本發明之第一實施例之顯示 系統之示意圖。本實施例係以位相差板為四分之一波板、 透光基板為玻璃基板、偏振影像光為圓偏振影像光或橢圓 偏振影像光為例做說明。如第1圖所示，顯示系統1〇〇包 ❹括影像裝置102、玻璃基板130及四分之一波板110。玻 璃基板130具有相對之一第一表面130A及一第二表面 130B。四分之一波板U0配置於玻璃基板130之第一表面 130A上。四分之一波板110具有相對之上表面110B與下 表面110A。 由影像裝置1〇2產生之圓偏振影像光或橢圓偏振影 像光將以入射角01為布魯斯特(Brewster)角之方式射向四 分之一波板β部份之圓偏振影像光或橢圓偏振影像光 TW4268PA-C2 5 200935090 經四分之一波板110之下表面110A反射之後，係朝向— 觀測方向D1射出，以讓觀測者104可以看到所對應之影 像。而其他部份之圓偏振影像光或橢圓偏振影像光會穿^ 四分之一波板11〇，並射向玻璃基板13〇。 經由四分之一波板110處理後之圓偏振影像光或橢 圓偏振影像光會轉變線性偏振光，例如是p偏振影像光。 P偏振影像光從四分之一波板11〇之上表面11〇B射出後， 會射入玻璃基板130。由於圓偏振影像光或橢圓偏振影像 光於四分之一波板110之入射角Θ1為布魯斯特角，且第 一表面130Α與第二表面130Β為實質上平行，因此射向破 璃基板130之第二表面130Β時，其入射角Θ2亦將為布魯 斯特角。如此，由四分之一波板110射向玻璃基板13〇之 第二表面130Β之Ρ偏振影像光將會大部分地穿過第二表 面130Β，以射出玻璃基板130。 如此，由於大部分之入射至玻璃基板130Ρ之偏振影 像光將從玻璃基板130射出，而由第二表面130Β反射的ρ 偏振影像光將會很少，如此，觀測者140將幾乎不會看到 由玻璃基板130反射之光線，而可以有效地避免鬼影的產 生。 更進一步，影像裝置102可以藉由能夠直接產生圓偏 振影像光或橢圓偏振影像光之顯示器來達成。或者，影像 裝置102可以由一顯示器120與一四分之一波板150來達 成。四分之一波板150係設置於顯示器120的影像光出光 側’於本實施例中，四分之一波板150係鄰近顯示器12〇 TW4268PA-C2 6 200935090 設置。由顯示器120射出之—原始影像光經由四分之一波 板150之後’係產生圓偏振影像光或橢圓偏振影像光以射 向四刀之一波板110。原始影像光例如為S偏振影像光。 由顯不器120射出之8偏振影像光經由四分之一波板15〇 處理之後，將產生上述之圓偏振影像光或橢圓偏振影像 光。 藉由四分之一波板150的使用，可以使得顯示器120 射出之S偏振影像光得到補償，而使得於玻璃基板GO中 ❹傳遞的P偏振影像光為較純的p偏振影像光，而使消除鬼 影的效果更佳。 顯示系統100更可包括一角度調整裝置1〇4，用以調 整四分之一波板150之一光學轴i5〇a相對於顯示器no 之影像偏振片之光學軸12〇a之角度。如第3圖所示，此 角度例如約為35度至55度之間。角度調整裝置1〇4可以 是旋轉機構，例如是可承載四分之一波板150之可旋轉圓 盤。角度調整裝置104也可以是夾持機構，例如是可夾持 ®四分之一波板150兩側以進行旋轉之夾持機構。 上述之四分之一波板110係為雙折射材質，其可藉由 緊靠、黏貼或濺鍍的方式配置於玻璃基板130上，並位於 玻璃基板130與觀察者140之間。四分之一波板110亦可 用與四分之一波板110具有類似功能之位相差板替代。與 傳統之需經由特殊之製程以將二分之一波板或反射式偏 光片插入擋風玻璃中間的作法相較，本實施例具有製程容 易且容易實現於產品上之優點。 TW4268PA-C2 7 200935090 實施例二 請參照第2圖’其繪示乃本發明之第二實施例之顯示 系統之示意圖。與第-實施例不同的是，本實施例係以位 相差板為二分之-波板、偏振影像光為線性偏振影像光為 例做說明。此線性偏振影像光例如是s偏振影像光。如第 2圖所示，顯示系統300包括影像裝置3〇2、玻璃基板33〇 及二分之一波板310。玻璃基板33〇具有相對之一第一表 面330A及一第二表面330B。二分之一波板31〇配置於玻 璃基板330之第一表面330A上。二分之一波板31〇具有❹ 相對之上表面310B與下表面310A。 由影像裝置302產生之S偏振影像光將以入射角θ3 為布魯斯特角之方式射向二分之一波板31〇 ^部份之S偏 振影像光經二分之一波板310之下表面31〇Α反射之後， 係朝向觀測方向D2射出，以讓觀測者3〇4可以看到所對 應之影像。而其他部份之S偏振影像光會穿透二分之一波 板310，並射向玻璃基板330。 經由二分之一波板310處理後之8偏振影像光會轉變 Ο Ρ偏振影像光。Ρ偏振影像光從二分之一波板310之上表 面310Β射出後，會射入玻璃基板33〇。由於s偏振影像 光於一分之一波板310之入射角Θ3為布魯斯特角，且第 一表面330Α與第二表面330Β為實質上平行，因此射向玻 璃基板330之第二表面330Β時’其入射角04亦將為布魯 斯特角。如此，由二分之一波板310射向玻璃基板330之 第一表面330Β之Ρ偏振影像光將會大部分地穿過第二表 TW4268PA-C2 8 200935090 面330B，以射出玻璃基板330。 如此，由於射入玻璃基板330之大部分的p偏振影像 光將從玻璃基板330射出，而由第二表面330B反射的p 偏振影像光將會很少，如此，觀測者340將幾乎不會看到 由玻璃基板330反射之光線，而可以有效地避免鬼影的產 生。 更進一步’影像装置302係由一顯示器320與一四分 之一波板350來達成。四分之一波板15〇係設置於顯示器 ❹120的影像光出光側，於本實施例’四分之一波板35〇係 鄰近顯示器320設置。由顯示器320射出之一原始影像光 經由四分之一波板350之後，係產生接近於s偏振態之糖 圓偏振影像光以射向二分之一波板310。原始影像光例如 為S偏振影像光。四分之一波板350將會使由顯示器320 射出之S偏振影像光得到補償效果，以使上述之二分之一 波板310中之P偏振影像光更為純化，而使消除鬼影的效 果更佳。 ® 顯示系統300更可包括一角度調整裝置3〇4，用以調 整四分之一波板350之一光學轴35〇a相對於顯示器320 之影像偏振片之光學軸320a之角度。如第4圖所示，此 角度例如約為-10度至1〇度之間。角度調整裝置可以 是旋轉機構，例如是可承載四分之一波板35〇之可旋轉之 圓盤。角度調整裝置304也可以是夾持機構，例如是可夾 持四分之一波板350兩側旋轉之夾持機構。 上述之一分之一波板310係為雙折射材質，其可藉由 TW4268PA-C2 9 200935090 緊靠、黏貼或濺鍍的方式配置於玻璃基板330上，並位於 玻璃基板330與觀察者340之間。二分之一波板310亦可 用與二分之一波板310具有類似功能之位相差板替代。與 傳統之需經由特殊之製程以將二分之一波板或反射式偏 光片插入擋風玻璃中間的作法相較，本實施例具有製程容 易且容易實現於產品上之優點。 實施例三 請參照第5圖，其繪示本發明實施例三的一種顯示系 統之示意圖。如第5圖所示，顯示系統500包括影像反射 元件510及偏光元件520。影像反射元件510包括基板512 及相位調變元件514，相位調變元件514鄰接基板512。 相位調變元件514具有一反射表面514a。 如第5圖所示，鬼影消除裝置500與影像裝置502組 成一顯示系統1。影像裝置502產生一偏振影像光pi。其 中’影像裝置502可以是一液晶顯示面板，偏振影像光pi 可以由液晶顯示面板所產生；影像裝置502也可以是一影 像偏光元件搭配一影像產生裝置，偏振影像光P1係由影 像產生裝置產生之影像光通過影像偏光元件後產生。反射 表面514a用以接收偏振影像光P1’偏振影像光pi經反射 表面514a反射後’反射表面514a反射部分之偏振影像光 P1以產生第一反射偏振影像光P2。部分之偏振影像光P1 射入相位調變元件514並由基板512反射後，由反射表面 514a射出以產生第二反射偏振影像光S2。 TW4268PA-C2 200935090 ，更進一步說明，偏振影像光pi為一線性偏振影像 光彳】如為p型線性偏振影像光，也就是光的偏振方向 f入射光及反射光之行進方向所構成之平面平行 ;也可以 疋或一 S型線性偏振影像光也就是光的偏振方向與入射 光及反射光之行進方向所構成之平面垂直。本實施例中， 偏振影像光P1係以P型線性偏振影像光為例作說明。但 本實施例不限於此，偏振影像光可以是不屬於p型或s型 之線性偏振影像光，也可以是圓偏振影像光或橢圓偏振影 ❹像光。 較佳地’基板512例如為一透光基板，例如透明玻璃 板或透明塑膠板。相位調變元件514例如為一貼附於基板 512上’由高分子材料形成之1/4波長板；或者是，相位 調變元件514可以是塗佈於基板512上之1/4波長塗層。 因此，當部分之偏振影像光P1進入相位調變元件514並 由基板512反射後射出相位調變元件514，所產生之第二 反射偏振影像光S2與原始偏振影像光pi之間產生18〇度 ® (π)的相位延遲或相位差；或者是，第二反射偏振影像光 S2與原始偏振影像光Ρ1之間產生n;r的相位延遲或相位 差’其中η為1、3、5…之正奇數。因此，第一反射偏振 影像光Ρ2與第二反射偏振影像光S2之偏振方向實質上相 互垂直。也就是說，第二反射偏振影像光S2係為S槊線 性偏振影像光。 如第5圖所示’第一反射偏振影像光Ρ2及第二反射 偏振影像光S2同時射向偏光元件520。較佳地，偏光元件 TW4268PA-C2 11 200935090 520例如為一 P型偏光板，因此可以允許第一反射偏振影 像光P2通過成為接收偏振影像光P3，同時遮擋第二反射 偏振影像光S2。同樣的，即使部分之偏振影像光ρι係通 過相位調變元件514,經由基板512反射表面512a反射並 通過相位調變元件514而產生一第三反射偏振影像光 S3 ’第三反射偏振影像光S3之偏振方向仍然和第一反射 偏振影像光P2之偏振方向實質上相互垂直，因此無法通 過偏光元件520。惟本實施例雖然以1/4波長板為例作說 明，但本發明不限於此。只要波長板的延遲波長滿足關係 式（1)’即可造成相同的相位延遲： 4λ+2Π'λ ⑴ 其中’ η為包含〇之非負整數，又表示第二反射偏振 影像光之波長。 此外，即使偏振影像光可以是不屬於Ρ型或S型之線 性偏振影像光’第一反射偏振影像光與通過1/4波長板兩 次的第二反射偏振影像光之偏振方向仍會相互垂直。因 此，只要調整偏光元件520的偏光轴與第一反射偏振影像 光之偏振方向一致，偏光元件520仍可讓第一反射偏振影 像光通過並遮擋第二反射偏振影像光。 另外，若偏振影像光為圓形或橢圓形偏振影像光，第 一反射偏振影像光與通過1/4波長板兩次的第二反射偏振 影像光的旋光方向會相反。因此，只要採用旋光方向與第 一反射偏振影像光相同的圓偏光板做為偏光元件，圓偏光 板仍可讓第一反射偏振影像光通過並遮擒第二反射偏振 TW4268PA-C2 ” 200935090 影像光。 此外，本實施例雖以線性偏振影像光為例做說明，但 亦可適用於圓形偏振影像光及橢圓偏振影像光。只要第一 反射光及第二反射光在通過偏光單元520時分別具有不同 之偏振方向’使得偏光單元520能夠讓第一反射偏振影像 光通過並濾除第二反射偏振影像光，皆落於本發明之保護 A-Ar rS] 範圍。 因此，只要是曾經通過相位調變元件514的反射偏振 ❹影像光’都可以經由偏光元件520濾除，避免多次反射光 形成鬼影影像。 此外，如果偏振影像光P1為彩色光，則相位調變元 件514之波長可以依相位調變元件對光波長的相位調變變 化的特性來選用適當的波長來進行相位調變量設計，以減 少色差的產生。 實施例四 請參照第6圖’其繪示本發明實施例二的一種顯示系 統之示意圖。如第3圖所示’鬼影消除裝置6〇〇包括透光 基板610及相位調變元件620，相位調變元件620鄰接透 光基板610 »相位調變元件620具有反射表面62〇a。 如第6圖所示，鬼影消除裝置600與影像裝置602組 成一顯示系統3’亦即為一抬頭顯示器。影像裝置602產 生偏振影像光TE1 ’反射表面620a用以接收偏振影像光 TE1，反射表面620a反射部分之偏振影像光TE1以產生反 TW4268PA-C2 13 200935090 射偏振影像光TE2。部分之偏振影像光TE1射入相位調變 元件620後成為入射偏振影像光TM2。入射低娘旦，你土 TM2被相位調變元件620調整成具有一所欲之偏振向， 使得大部分之該入射偏振影像光TM2係射入读本装把 仙。影像裝請可以是-液晶顯示面板射== TE1係由液晶顯示面板所產生；影像裝置6〇2也可以是一 影像偏光元件搭配一影像產生裝置’偏振影像光TE1係由 影像產生裝置產生之影像光通過影像偏光元件後產生。較 佳地’偏振影像光TE1係為線性偏振影像光。本實施例中 偏振影像光TE1同時亦屬於TE電磁波，也就是偏振方向 與入射平面垂直的電磁波。 較佳地，透光基板610係為一玻璃板及一透明塑膠板 其中之一。相位調變元件620係為設置於透光基板61〇上 之一 1/2波長板；或者是，相位調變元件62〇係為塗佈於 透光基板610上之一 1/2波長塗層^若反射偏振影像光TE2 屬於TE電磁波，如第3圖所示，部分之偏振影像光TE1 射入相位調變元件620後，入射偏振影像光TM2與反射 偏振影像光TE2之間產生η π的相位延遲或相位差，其中 η為1、3、5…之正奇數。經過相位調變元件62〇調變後 之入射偏振影像光ΤΜ2係屬於ΤΜ電磁波，也就是偏振方 向與入射平面平行的電磁波。 如第6圖所示，入射偏振影像光τμ2係以入射角<9 進入透光基板610。當入射偏振影像光ΤΜ2進入透光基板 610之入射角（9 ’與相位調變元件220及透光基板210間 TW4268PA-C2 14 200935090 之布魯斯特角（Brewster’s angle)之差距小於約15度時，由 於入射偏振影像光TM2係屬於TM電磁波，所以入射偏振 影像光TM2可在反射率極低的情沉下進入透光基板610， 並通過透光基板610射出。因此，大部分進入相位調變元 件620後之入射偏振影像光TM2不會再被透光基板610 反射進入觀賞者眼中，故可以有效消除多餘反射影像光所 造成之鬼影現象。 ❹ ❾ 更進一步說明，當入射角Θ接近相位調變元件620與 透光基板610間之布魯斯特角時，入射偏振影像光TM2 可在幾乎不反射的情況下通過透光基板61〇〇請參照第7 圖，其繪示本發明實施例二之鬼影消除裝置於不同入射角 下對於TE電磁波及TM電磁波之反射率。如第4圖所示， 區域I代表光由透光基板610進入相位調變元件62〇之情 境’區域II代表光由相位調變元件620進入透光基板61〇 之情境。本實施例中，相位調變元件020採用高分子材料， 透光基板610採用透明玻璃板。因此在區域π之情境時， 如曲線401所示，ΤΜ電磁波之布魯斯特角約為％度。 因此’當入射角Θ位於40-70度之間時，入射偏振影像&光 ΤΜ2由相位調變元件620進入透光基板61〇的反射率皆小 於10%。由此可知，影像裝置602可適當調整其位置使 入射偏振影像光ΤΜ2的入射角0盡量接近布魯斯特角Θ β ’以減少入射偏振影像光ΤΜ2反射的比例。當入射端介 質之折射係數為ni，出射端介質之折射係數為叫，布魯斯 特角0B可以公式(2)計算： TW4268PA-C2 15 (2) 200935090 ΘΒ =tan'* —200935090 VI. Description of the Invention: [Technical Field] The present invention relates to a display system, and more particularly to a display system capable of eliminating ghost images. [Prior Art] In order to improve the driving safety of motorists, cars have been designed to project driving information such as vehicle speed or motor speed on the windshield for display to the driver. However, in today's technology, whether it is a virtual image imaging method or a real image imaging method, the image has ghosting problems, and the driver cannot clearly recognize the display on the windshield glass. Driving information. A variety of techniques for eliminating ghosting have been proposed. In U.S. Patent No. 5,999,314, a half-wave plate is placed in the middle of the windshield to eliminate ghosting. This method requires an additional Brewster film to meet the low brightness loss and special handling of the windshield. A method of inserting a one-half wave plate into a windshield glass is disclosed in U.S. Patent No. 5,212,471. A method of placing a reflective polarizer in a windshield is mentioned in U.S. Patent No. 7,123,418. This reflective polarizer blocks light entering from the outside, making it impossible for the driver to see through the reflected polarized light behind the subject. SUMMARY OF THE INVENTION The present invention provides a display system including an image device, a light transmissive substrate, and a single phase difference plate. The imaging device is configured to generate a polarized image light. TW4268PA-C2 1 200935090 The light transmissive substrate has a first surface and a second surface. The phase difference plate is disposed on the first surface of the light transmissive substrate. Wherein, part of the polarized image light is reflected by the phase difference plate, and is emitted toward a direction of observation, and after the polarized image light of the other portion penetrates the phase difference plate, most of the light is emitted from the second surface. The present invention provides a display system including an image device, an image reflecting element, and a polarizing element. The imaging device is used to generate a polarized image light. The image reflecting element comprises a substrate and a phase modulation element. The phase modulation element is adjacent to the substrate, and the phase modulation element has a reflective surface for receiving polarized image light. After the polarized image light is incident on the reflective surface, the reflective surface reflects a portion of the polarized image light to generate a first reflected polarized image light, and part of the polarized image light is incident on the phase modulation element, and is reflected by the substrate and then emitted by the reflective surface. To generate a second reflected polarized image light. The phase difference between the first reflected polarized image light and the second reflected polarized image light is substantially ηττ, and η is a positive odd number. The polarizing element is configured to receive and pass the first reflected polarized image light and shield the second reflected polarized image light. The invention provides a display system comprising an image device, a light transmissive substrate and a phase modulation element. The imaging device is used to generate a polarized image light. The phase modulation element is adjacent to the light transmissive substrate, and the phase modulation element has a reflective surface for receiving polarized image light. When the polarized image light is incident on the reflective surface, the polarized image light of the portion of the reflected surface of the reflective surface is reflected to generate a reflected polarized image light. The polarized image light is incident on the phase modulation element and becomes an incident polarized image light. Having a desired polarization direction is such that most of the incident polarized image light penetrates the light transmissive substrate. TW4268PA-C2 4 200935090 In order to make the above description of the present invention more obvious, the following detailed description of the preferred embodiments, together with the accompanying drawings, will be described in detail as follows: [Embodiment] The present invention discloses a display system. The invention comprises an image device, a transparent substrate and a phase difference plate. The imaging device is used to generate a polarized image light. The light transmissive substrate has a first surface and a second surface. The phase difference plate is disposed on the first surface of the light transmissive substrate. Wherein, part of the polarized image light is reflected by the phase difference plate, and is emitted toward a direction of observation, and most of the polarized image light is transmitted through the phase difference plate, and is mostly emitted by the second surface. Embodiment 1 Referring to Figure 1, there is shown a schematic diagram of a display system in accordance with a first embodiment of the present invention. In this embodiment, the phase difference plate is a quarter-wave plate, the transparent substrate is a glass substrate, and the polarized image light is circularly polarized image light or elliptically polarized image light. As shown in Fig. 1, the display system 1 includes an image device 102, a glass substrate 130, and a quarter-wave plate 110. The glass substrate 130 has a first surface 130A and a second surface 130B opposite to each other. The quarter-wave plate U0 is disposed on the first surface 130A of the glass substrate 130. The quarter-wave plate 110 has a relatively upper surface 110B and a lower surface 110A. The circularly polarized image light or the elliptically polarized image light generated by the image device 1〇2 will be directed to the circularly polarized image light or elliptically polarized portion of the quarter wave plate β portion at an incident angle of 01 as a Brewster angle. The image light TW4268PA-C2 5 200935090 is reflected by the lower surface 110A of the quarter wave plate 110, and is emitted toward the observation direction D1 so that the observer 104 can see the corresponding image. The other part of the circularly polarized image light or the elliptically polarized image light will pass through the quarter-wave plate 11〇 and be directed to the glass substrate 13〇. The circularly polarized image light or the elliptically polarized image light processed by the quarter wave plate 110 converts linearly polarized light, such as p-polarized image light. The P-polarized image light is emitted from the upper surface 11〇B of the quarter-wave plate 11〇, and is incident on the glass substrate 130. Since the incident angle Θ1 of the circularly polarized image light or the elliptically polarized image light on the quarter wave plate 110 is a Brewster angle, and the first surface 130Α is substantially parallel to the second surface 130Β, the light is incident on the glass substrate 130. When the second surface 130 is Β, its incident angle Θ2 will also be the Brewster angle. Thus, the polarized image light that is directed by the quarter-wave plate 110 toward the second surface 130 of the glass substrate 13 will pass through the second surface 130A to emit the glass substrate 130. Thus, since most of the polarized image light incident on the glass substrate 130 is emitted from the glass substrate 130, the ρ-polarized image light reflected by the second surface 130Β will be small, and thus the observer 140 will hardly see it. The light reflected by the glass substrate 130 can effectively avoid the generation of ghosts. Furthermore, the image device 102 can be realized by a display capable of directly generating circularly polarized image light or elliptically polarized image light. Alternatively, imaging device 102 can be implemented by a display 120 and a quarter-wave plate 150. The quarter-wave plate 150 is disposed on the image light exit side of the display 120. In the present embodiment, the quarter-wave plate 150 is disposed adjacent to the display 12 TW4268PA-C2 6 200935090. The original image light emitted by the display 120 passes through the quarter wave plate 150 to generate circularly polarized image light or elliptically polarized image light to be directed to the four-blade wave plate 110. The original image light is, for example, S-polarized image light. The 8-polarized image light emitted by the display 120 is processed by the quarter-wave plate 15〇 to produce the above-described circularly polarized image light or elliptically polarized image light. By using the quarter-wave plate 150, the S-polarized image light emitted by the display 120 can be compensated, so that the P-polarized image light transmitted by the germanium in the glass substrate GO is purer p-polarized image light, so that The effect of eliminating ghosts is better. The display system 100 further includes an angle adjusting device 1〇4 for adjusting the angle of the optical axis i5〇a of one of the quarter wave plates 150 with respect to the optical axis 12〇a of the image polarizing plate of the display no. As shown in Fig. 3, this angle is, for example, approximately between 35 and 55 degrees. The angle adjusting device 1〇4 may be a rotating mechanism such as a rotatable disk that can carry the quarter-wave plate 150. The angle adjusting device 104 may also be a clamping mechanism, such as a clamping mechanism that can hold the sides of the quarter-wave plate 150 for rotation. The quarter-wave plate 110 is a birefringent material which can be disposed on the glass substrate 130 by abutting, pasting or sputtering, and located between the glass substrate 130 and the viewer 140. The quarter-wave plate 110 can also be replaced with a phase difference plate having a similar function to the quarter-wave plate 110. Compared with the conventional method of inserting a half-wave plate or a reflective polarizer into the middle of the windshield through a special process, the present embodiment has the advantages of easy process and easy realization on the product. TW4268PA-C2 7 200935090 Embodiment 2 Referring to Figure 2, there is shown a schematic diagram of a display system in accordance with a second embodiment of the present invention. Different from the first embodiment, the present embodiment is described by taking a phase difference plate as a two-wave plate and a polarized image light as a linearly polarized image light. This linearly polarized image light is, for example, s-polarized image light. As shown in Fig. 2, the display system 300 includes an image device 3A, a glass substrate 33A, and a half wave plate 310. The glass substrate 33 has a pair of first surface 330A and a second surface 330B. The one-half wave plate 31 is disposed on the first surface 330A of the glass substrate 330. The one-half wave plate 31 has a top surface 310B and a lower surface 310A. The S-polarized image light generated by the image device 302 is directed toward the half-wave plate 31 by the incident angle θ3 as the Brewster angle. The S-polarized image light passes through the lower surface of the half-wave plate 310. After the 31〇Α reflection, it is emitted toward the observation direction D2, so that the observer 3〇4 can see the corresponding image. The other portions of the S-polarized image light will penetrate the half-wave plate 310 and be directed toward the glass substrate 330. The 8-polarized image light processed by the half-wave plate 310 converts the Ο Ρ polarized image light. The pupil polarized image light is emitted from the upper surface 310 of the half-wave plate 310, and is incident on the glass substrate 33A. Since the incident angle Θ3 of the s-polarized image light on the one-wave plate 310 is a Brewster angle, and the first surface 330Α is substantially parallel to the second surface 330Β, when the second surface 330 of the glass substrate 330 is incident, Its angle of incidence 04 will also be the Brewster angle. Thus, the polarized image light from the first wave plate 310 of the first surface 330 of the glass substrate 330 will pass through the second surface TW4268PA-C2 8 200935090 face 330B to emit the glass substrate 330. Thus, since most of the p-polarized image light incident on the glass substrate 330 will be emitted from the glass substrate 330, the p-polarized image light reflected by the second surface 330B will be small, and thus the observer 340 will hardly see. The light reflected by the glass substrate 330 can effectively avoid the generation of ghosts. Further, the image device 302 is realized by a display 320 and a quarter-wave plate 350. The quarter-wave plate 15 is disposed on the image light exiting side of the display port 120, and is disposed adjacent to the display 320 in the embodiment 'quarter-wave plate 35'. After the original image light is emitted from the display 320 via the quarter-wave plate 350, the circularly polarized image light of the s-polarized state is generated to be directed toward the half-wave plate 310. The original image light is, for example, S-polarized image light. The quarter-wave plate 350 will compensate the S-polarized image light emitted by the display 320 to further purify the P-polarized image light in the one-half wave plate 310, thereby eliminating ghosting. The effect is better. The display system 300 can further include an angle adjustment device 〇4 for adjusting the angle of one of the optical axes 35〇a of the quarter wave plate 350 relative to the optical axis 320a of the image polarizer of the display 320. As shown in Fig. 4, this angle is, for example, approximately -10 degrees to 1 degree. The angle adjusting means may be a rotating mechanism such as a rotatable disc which can carry a quarter-wave plate 35 turns. The angle adjusting device 304 may also be a clamping mechanism, for example, a clamping mechanism that can rotate both sides of the quarter-wave plate 350. The one-by-one wave plate 310 is a birefringent material, which can be disposed on the glass substrate 330 by TW4268PA-C2 9 200935090 in close contact, pasting or sputtering, and is located on the glass substrate 330 and the observer 340. between. The one-half wave plate 310 can also be replaced with a phase difference plate having a similar function to the one-half wave plate 310. Compared with the conventional method of inserting a half-wave plate or a reflective polarizer into the middle of the windshield through a special process, the present embodiment has the advantages of easy process and easy realization on the product. Embodiment 3 Referring to Figure 5, a schematic diagram of a display system according to Embodiment 3 of the present invention is shown. As shown in FIG. 5, the display system 500 includes an image reflecting element 510 and a polarizing element 520. The image reflective element 510 includes a substrate 512 and a phase modulation element 514 that is adjacent to the substrate 512. Phase modulation element 514 has a reflective surface 514a. As shown in Fig. 5, ghost removal device 500 and video device 502 form a display system 1. Image device 502 produces a polarized image light pi. The image device 502 can be a liquid crystal display panel, and the polarized image light pi can be generated by the liquid crystal display panel. The image device 502 can also be an image polarizing element coupled with an image generating device. The polarized image light P1 is generated by the image generating device. The image light is generated after passing through the image polarizing element. The reflective surface 514a is configured to receive the polarized image light P1. The polarized image light pi is reflected by the reflective surface 514a and the reflective surface 514a reflects the partially polarized image light P1 to generate the first reflected polarized image light P2. Part of the polarized image light P1 is incident on the phase modulation element 514 and reflected by the substrate 512, and is then emitted by the reflective surface 514a to produce the second reflected polarized image light S2. TW4268PA-C2 200935090, further illustrating that the polarized image light pi is a linearly polarized image diaphragm] such as p-type linearly polarized image light, that is, the polarization direction of the light f is parallel to the plane of the direction of travel of the reflected light. It is also possible to 疋 or an S-type linearly polarized image light, that is, the polarization direction of the light is perpendicular to the plane formed by the direction of travel of the incident light and the reflected light. In this embodiment, the polarized image light P1 is exemplified by P-type linearly polarized image light. However, the embodiment is not limited thereto, and the polarized image light may be a linearly polarized image light that is not a p-type or an s-type, or may be a circularly polarized image light or an elliptically polarized image light. Preferably, the substrate 512 is, for example, a light transmissive substrate such as a transparent glass plate or a transparent plastic plate. The phase modulation element 514 is, for example, a quarter-wave plate formed of a polymer material attached to the substrate 512; or the phase modulation element 514 may be a quarter-wave coating coated on the substrate 512. . Therefore, when a part of the polarized image light P1 enters the phase modulation element 514 and is reflected by the substrate 512 and then exits the phase modulation element 514, the generated second reflected polarized image light S2 and the original polarized image light pi generate 18 degrees. ® (π) phase delay or phase difference; or, between the second reflected polarized image light S2 and the original polarized image pupil 1 produces n; r phase delay or phase difference 'where η is 1, 3, 5... Positive odd number. Therefore, the polarization directions of the first reflective polarized image aperture 2 and the second reflected polarized image light S2 are substantially perpendicular to each other. That is, the second reflected polarized image light S2 is S linearly polarized image light. As shown in Fig. 5, the first reflective polarized image stop 2 and the second reflected polarized image light S2 are simultaneously incident on the polarizing element 520. Preferably, the polarizing element TW4268PA-C2 11 200935090 520 is, for example, a P-type polarizing plate, so that the first reflected polarized image light P2 can be allowed to pass through the received polarized image light P3 while blocking the second reflected polarized image light S2. Similarly, even if part of the polarized image light ρι passes through the phase modulation element 514, it is reflected by the reflective surface 512a of the substrate 512 and passes through the phase modulation element 514 to generate a third reflective polarized image light S3 'the third reflected polarized image light S3. The polarization direction is still substantially perpendicular to the polarization direction of the first reflected polarized image light P2, and therefore cannot pass through the polarizing element 520. However, although the present embodiment is described by taking a 1/4 wavelength plate as an example, the present invention is not limited thereto. As long as the retardation wavelength of the wavelength plate satisfies the relationship (1)', the same phase delay can be caused: 4λ+2Π'λ (1) where 'η is a non-negative integer containing 〇 and represents the wavelength of the second reflected polarized image light. In addition, even if the polarized image light may be a linearly polarized image light that is not of a Ρ type or an S type, the polarization direction of the first reflected polarized image light and the second reflected polarized image light twice passed through the 1/4 wavelength plate will still be perpendicular to each other. . Therefore, as long as the polarization axis of the polarizing element 520 is adjusted to coincide with the polarization direction of the first reflected polarized image light, the polarizing element 520 can pass the first reflected polarized image light and block the second reflected polarized image light. In addition, if the polarized image light is circular or elliptical polarized image light, the direction of the first reflective polarized image light and the second reflected polarized image light passing through the quarter wave plate twice will be opposite. Therefore, as long as a circular polarizing plate having the same optical rotation direction as the first reflected polarized image light is used as the polarizing element, the circular polarizing plate can still pass the first reflected polarized image light and conceal the second reflective polarized light TW4268PA-C2" 200935090 image light In addition, although the linear polarization image light is taken as an example, the present embodiment is applicable to the circularly polarized image light and the elliptically polarized image light, as long as the first reflected light and the second reflected light pass through the polarizing unit 520 respectively. Having different polarization directions ′ such that the polarizing unit 520 can pass the first reflected polarized image light and filter out the second reflected polarized image light, all fall within the protection A-Ar rS] range of the present invention. The reflected polarization ❹ image light ′ of the modulating element 514 can be filtered through the polarizing element 520 to prevent the multi-reflected light from forming a ghost image. Further, if the polarized image light P1 is colored light, the wavelength of the phase modulating element 514 can be According to the characteristics of the phase modulation component changing the phase of the optical wavelength, the appropriate wavelength is selected to perform the phase modulation design to reduce Embodiment 4 Please refer to FIG. 6 for a schematic diagram of a display system according to Embodiment 2 of the present invention. As shown in FIG. 3, the ghost removal device 6 includes a transparent substrate 610 and phase adjustment. The variable element 620, the phase modulation element 620 is adjacent to the transparent substrate 610. The phase modulation element 620 has a reflective surface 62〇a. As shown in FIG. 6, the ghost removing device 600 and the imaging device 602 form a display system 3'. That is, a head-up display. The image device 602 generates a polarized image light TE1. The reflective surface 620a receives the polarized image light TE1, and the reflective surface 620a reflects a portion of the polarized image light TE1 to generate a reverse TW4268PA-C2 13 200935090 polarized image light TE2. Part of the polarized image light TE1 enters the phase modulation element 620 and becomes the incident polarized image light TM2. When the incident is low, the earth TM2 is adjusted by the phase modulation element 620 to have a desired polarization direction, so that most of the The incident polarized image light TM2 is incident on the reader. The image can be - liquid crystal display panel == TE1 is generated by the liquid crystal display panel; the image device 6〇2 can also be a shadow The polarizing image is combined with an image generating device 'polarized image light TE1>, and the image light generated by the image generating device is generated by the image polarizing element. Preferably, the 'polarized image light TE1 is linearly polarized image light. In this embodiment, the polarized image is polarized. The light TE1 also belongs to the TE electromagnetic wave, that is, the electromagnetic wave whose polarization direction is perpendicular to the incident plane. Preferably, the transparent substrate 610 is one of a glass plate and a transparent plastic plate. The phase modulation component 620 is disposed on the One of the 1/2 wavelength plates on the transparent substrate 61; or the phase modulation element 62 is a 1/2 wavelength coating applied on the transparent substrate 610. If the reflected polarized image light TE2 belongs to TE As shown in FIG. 3, after a part of the polarized image light TE1 is incident on the phase modulation element 620, a phase delay or phase difference of η π is generated between the incident polarized image light TM2 and the reflected polarized image light TE2, wherein η is Positive odd number of 1, 3, 5... The incident polarization image pupil 2 after being modulated by the phase modulation element 62 is a ΤΜ electromagnetic wave, that is, an electromagnetic wave whose polarization direction is parallel to the incident plane. As shown in Fig. 6, the incident polarized image light τμ2 enters the light-transmitting substrate 610 at an incident angle <9. When the incident angle of the incident polarized image stop 2 into the transparent substrate 610 (the difference between 9' and the Brewster's angle of the phase modulation element 220 and the transparent substrate 210 TW4268PA-C2 14 200935090 is less than about 15 degrees, Since the incident polarized image light TM2 belongs to the TM electromagnetic wave, the incident polarized image light TM2 can enter the transparent substrate 610 under the extremely low reflectance and is emitted through the transparent substrate 610. Therefore, most of the input phase modulation components are entered. The incident polarized image light TM2 after 620 is no longer reflected by the transparent substrate 610 into the viewer's eye, so the ghost phenomenon caused by the extra reflected image light can be effectively eliminated. ❹ ❾ Further explanation, when the incident angle Θ is close to the phase adjustment When the Brewster angle between the variable element 620 and the transparent substrate 610, the incident polarized image light TM2 can pass through the transparent substrate 61 with little reflection, please refer to FIG. 7 , which illustrates the second embodiment of the present invention. The reflectance of the ghost removing device for the TE electromagnetic wave and the TM electromagnetic wave at different incident angles. As shown in Fig. 4, the region I represents the phase in which the light enters the phase modulation from the transparent substrate 610. The situation of the variable element 62 区域 region II represents the situation where the light enters the transparent substrate 61 by the phase modulation element 620. In the embodiment, the phase modulation element 020 is made of a polymer material, and the transparent substrate 610 is made of a transparent glass plate. Therefore, in the context of the region π, as shown by the curve 401, the Brewster angle of the electromagnetic wave is about %. Therefore, when the incident angle Θ is between 40 and 70 degrees, the incident polarization image & The reflectance of the variable element 620 into the transparent substrate 61 is less than 10%. It can be seen that the image device 602 can appropriately adjust its position so that the incident angle 0 of the incident polarized image stop 2 is as close as possible to the Brewster angle Θ β ' to reduce incidence. The ratio of the reflection of the polarized image pupil 2. When the refractive index of the medium at the incident end is ni, the refractive index of the medium at the exit end is called, and the Brewster angle 0B can be calculated by the formula (2): TW4268PA-C2 15 (2) 200935090 ΘΒ =tan' * —
Hi 惟本實施例之相位調變元件雖然以l/2波長板為例作 說明，但本發明不限於此。只要波長板的延遲波長滿足關 係式（3) ’即可造成相同的相位延遲： 臺 λ+η.λ (3) 其中，η為包含〇之非負整數，λ表示入射偏振影像 光之波長。 另外，若偏振影像光係為一圓偏振影像光或一橢圓偏❹ 振影像光，相位調變元件可以是設置於透光基板61〇上之 一 1/4波長板，或者是塗佈於透光基板61〇上之一 1/4波 長塗層。因此，部分之偏振影像光射入相位調變元件後所 產生之入射偏振影像光轉變成線性偏振影像光，並調整其 偏振方向為ΤΜ電磁波。因此，只要保持入射偏振影像光 入射透光基板610的角度接近相位調變元件與透光基板 610間之布魯斯特角，亦可達到降低反射率之功效。 此外，即使偏振影像光TE1為彩色光，則相位調變 〇 70件614之波長可以依相位調變元件對光波長的相位調變 變化的特性來選用適當的波長來進行相位調變量設計，可 以減少色差的產生’同時維持大多數入射偏振影像光的低 反射率。 綜上所述，雖然本發明已以較佳實施例揭露如上然 其並非用以限定本發明。本發明所屬技術領域中具有通常 知識者，在不脫離本發明之精神和範圍内，當可作各種之 TW4268PAC2 1£ 200935090 更動與潤飾。因此，本發明之保護範圍當視後附之申請專 利範圍所界定者為準。 【圖式簡單說明】 第1圖繪示乃本發明之第一實施例之顯示系統之示 意圖。 第2圖繪示乃本發明之第二實施例之顯示系統之示 意圖。 第3圖繪示第1圖之四分之一波板之光學轴與顯示器 之影像偏振片之光學轴的關係之一例。 第4圖繪示第2圖之四分之一波板之光學軸與顯示器 之影像偏振片之光學轴的關係之一例。 第5圖繪示乃本發明之第三實施例之顯示系統之示 意圖。 第6圖繪示乃本發明之第四實施例之顯示系統之示 意圖。 第7圖繪示本發明實施例四之鬼影消除裝置於不同 入射角下對於TE電磁波及TM電磁波之反射率。 TW4268PA-C2 17 200935090 【主要元件符號說明】 100、300、500、600 :顯示系統 102、202、502、602 :影像裝置 104、304 :角度調整裝置 110、310 :四分之一波板 IIOA、 310A :下表面 IIOB、 310B ··上表面 120、320 :顯示器 130、330 :玻璃基板 130A、330A :第一表面 130B、330B :第二表面 140、340 :觀察者 150、350 :四分之一波板 150a、350a :四分之一波板之光學轴 120a、320a :顯示器之影像偏振片之光學轴 514a、620a :反射表面 502、602 :影像裝置 100、200 :鬼影消除裝置 510 :影像反射元件 512 :基板 514、620 :相位調變元件 520 :偏光元件 210 :透光基板 401 :曲線 TW4268PA-C2 18Hi Although the phase modulation element of the present embodiment is exemplified by a l/2 wavelength plate, the present invention is not limited thereto. As long as the retardation wavelength of the wavelength plate satisfies the relationship (3)', the same phase delay can be caused: λ + η. λ (3) where η is a non-negative integer containing 〇, and λ represents the wavelength of the incident polarized image light. In addition, if the polarized image light is a circularly polarized image light or an elliptically polarized image light, the phase modulation component may be a quarter-wave plate disposed on the transparent substrate 61 or coated with light. One 1/4 wavelength coating is applied to the substrate 61. Therefore, part of the polarized image light is incident on the phase modulation element, and the incident polarization image light is converted into linearly polarized image light, and the polarization direction thereof is adjusted to be a ΤΜ electromagnetic wave. Therefore, as long as the incident polarized image light is incident on the transparent substrate 610 at an angle close to the Brewster angle between the phase modulation element and the transparent substrate 610, the effect of reducing the reflectance can be achieved. In addition, even if the polarized image light TE1 is colored light, the wavelength of the phase modulation 〇70 614 can be selected according to the phase modulation characteristic of the phase modulation element to change the phase of the optical wavelength, and the phase modulation variable can be selected. Reduce the generation of chromatic aberrations while maintaining the low reflectivity of most incident polarized image light. In view of the above, the present invention has been disclosed in the preferred embodiments, which are not intended to limit the invention. TW4268PAC2 1£ 200935090 can be modified and retouched without departing from the spirit and scope of the present invention. Therefore, the scope of the invention is defined by the scope of the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a view showing a display system of a first embodiment of the present invention. Fig. 2 is a view showing the display system of the second embodiment of the present invention. Fig. 3 is a view showing an example of the relationship between the optical axis of the quarter-wave plate of Fig. 1 and the optical axis of the image polarizing plate of the display. Fig. 4 is a view showing an example of the relationship between the optical axis of the quarter-wave plate of Fig. 2 and the optical axis of the image polarizing plate of the display. Fig. 5 is a view showing the display system of the third embodiment of the present invention. Fig. 6 is a view showing the display system of the fourth embodiment of the present invention. Figure 7 is a diagram showing the reflectance of the ghost removing device of the fourth embodiment of the present invention for TE electromagnetic waves and TM electromagnetic waves at different incident angles. TW4268PA-C2 17 200935090 [Description of main component symbols] 100, 300, 500, 600: display systems 102, 202, 502, 602: imaging devices 104, 304: angle adjustment devices 110, 310: quarter-wave plate IIOA, 310A: lower surface IIOB, 310B · upper surface 120, 320: display 130, 330: glass substrate 130A, 330A: first surface 130B, 330B: second surface 140, 340: observer 150, 350: quarter Wave plates 150a, 350a: optical axes 120a, 320a of the quarter wave plate: optical axes 514a, 620a of the image polarizer of the display: reflective surfaces 502, 602: image devices 100, 200: ghost removal device 510: image Reflecting element 512: substrate 514, 620: phase modulation element 520: polarizing element 210: transparent substrate 401: curve TW4268PA-C2 18