200914876 九、發明說明： 【發明所屬之技術領域】 ' 本發明關於一種投影光學系統，尤其係一種具有高 對比度之立體投影光學系統。 【先前技術】 近年來，圖像投影儀，尤其數位投影儀，作為向觀 眾顯示複數訊息的工具已經逐漸流行。一般，這些投影 儀用於將由電腦生成之圖像投影到螢幕上。對觀看者來 說，圖像投影儀投影之圖像通常看起來係平面二維圖 像，除圖像本身外無法顯示任何圖像景深訊息。這種顯 示可以適用於顯示複數訊息。但是，在某些情況下，觀 看者希望能有比二維顯示能夠更大程度地顯示圖像之景 深或結構特徵之投影儀。 使二維顯示之圖像能給出圖像景深之一種方式係通 過立體地顯示圖像。立體圖像，通常稱為“三維”或 “3D”圖像，在觀看者看來具有深度尺寸。這些圖像包 ' 括分開的、疊合之左眼及右眼圖像，這些圖像設置成模 仿人之左右眼觀看時，由於人眼睛間隔引起之三維物體 表面之微小差別，而具有之景深圖像。左眼及右眼圖像 係這樣顯不的’即觀看者之右眼看不到左眼圖像’左眼 看不到右眼圖像。這種顯示方式一般借助於觀看者佩戴 之光學濾光鏡。 通常之立體投影光學系統都包括有一用於將入射光 分解成不同偏振方向之偏振分束器以及用於通過不同偏 200914876 振光產生左眼圖像及右眼圖像之左圖像產生元件及右圖 像產生元件。通過將左、右圖像產生元件產生之左、右 • 眼圖像投射到螢幕上，當人之左右眼戴上不同偏振方向 的眼鏡，便可看到立體之圖像。 但是當光從偏振分束器中射出後，在出射光中含有 雜亂光，該雜亂光之存在，部分原因係所有之實光學元 件所固有之光學特徵所導致之圖像雜訊，如偏振分束器 在接收高水準之光通量時，其一般變成熱負荷並且發生 : 物理扭曲而引起應力雙折射，這種應力雙折射會導致光 的去偏振及對比度之降低，還有一原因係所述偏振光分 別在各自之左、右圖像產生元件上接收空間訊息外，還 會接收到由所述偏振光光路上之其他光，如偏振光束分 離器等光學元件材料中之雙折射所產生之雜亂空間訊 息’而這些雜亂光沒有在被投射到顯7F器之前有效地將 其雜訊分離並排除，這些圖像雜訊及雜亂空間訊息會降 低投影到螢幕之出射光之對比度。 、 【發明内容】 有鑒於此，有必要提供一種能夠提高對比度之立體 投影光學系統。 一種立體投影光學系統，其包括依光路設置之： 一圖像吸收器，用於接收入射光，對該入射光進行 調制並載入空間訊息，並出射經調制並載入有空間訊息 之偏振方向垂直之第一偏振光及第二偏振光； 一檢偏器，其設置於所述圖像吸收器出射之第一偏 8 200914876 振光之出射光路上，用於使特定偏振方向之光通過； 一穿透式光調制器，設置於所述檢偏器出射之第一 偏振光之出射光路上，該穿透式光調制器具有開啟及截 止兩個交替之工作狀態，該穿透式光調制器處於開啟狀 態時，所述第一偏振光穿過所述穿透式光調制器，該穿 透式光調制器處於截止狀態時，所述穿透式光調制器將 入射的所述第一偏振光調制為第二偏振光並出射。 上述立體投影光學系統使用時可通過為穿透式光調 f 制器輸入訊號使得該穿透式光調制器具有開啟及截止兩 個交替之工作狀態，使得觀看者之左、右眼交替獲得不 同偏振狀態之影像，當該輸入訊號之頻率足夠快時，觀 看者之左右眼分別戴上檢偏方向相互垂直之兩片偏振 片，就可以觀察到立體之圖像訊息。同時利甩光路上設 置之檢偏器，在該檢偏器之作用下，允許特定偏振方向 之光通過而分離並排除了由實光學元件所固有之光學特 徵所導致之圖像雜訊以及由所述偏振光光路中之光學元 ' 件材料中之雙折射所產生之雜亂空間訊息，從而提昇了 所投影之出射光之對比度。 【實施方式】 下面將結合附圖，舉以下較佳實施例並配合圖式詳 細描述如下。 請參閱圖1及圖2，為本發明提供之第一實施例之立 體投影光學系統100之結構示意圖。該立體投影光學系 統100包括沿光路方向依次設置之一光源元件11、一圖 9 200914876 像吸收器12、-設置於所述圖像吸收器i2之一條出射 路上之檢偏H 13、-設置於所述檢偏器13出射光路上之 穿透式光調制器14以及一投影鏡頭15。 所述光源元件11包括依光路設置之-照明光源 111 &輪_112以及-積分器113。所述照明光源山 發射包括顯示彩色时所需之紅光(R)、綠光(g)及藍 之白光。^光源U可以為_素燈、金屬函化物燈、氙燈 或LED等。在本實施例中，該光源u為南素燈。所^ = '包括紅、綠、藍三色區，其可在電機(圖 的π動下而速旋轉，以給投影光路配以各種色彩。所成 積分i§ m用來均勻化及有效地使用光源u發出之光= 所述圖像吸收器12包括依光路設置之_偏振分束器 121及一反射式空間光調制器122。所述偏振分束器 (Polarization Beam Splitter，PBS) m 用於將來自光源元 件11之非偏振光變成第一偏振光及第二偏振光，在本實 靶例中所第一偏振光為s偏振光，第二偏振光為P偏振 光。該S偏振光被該偏振分束器121反射，而p偏振光 透過該偏振分束器121。該偏振分束器121可以為金屬柵 格型偏振片（Wire Grid Polarizer，簡稱WGP偏振片也 可以為偏振分光棱鏡，在本實施例中，該偏振分束器ΐ2ι 為偏振分光棱鏡。該偏振分束器l2l根據對8偏振光和p 偏振光之作用不同，可以分為反射S偏振光而透過p偏 振光’與透過S偏振光而反射P偏振光兩種形式。在本 實施例中，所述偏振分束器23反射S偏振光，而可以讓 200914876 p偏振光透過。 所述反射式空間光調制器122可以為石夕基液曰 (Liquid Crystal on Silicon, LCoS)顯示面板。該石夕基液曰 顯示面板工藝結構結合了液晶技術與半導體積體電路技 術。LCoS面板利用半導體制程製作驅動面板，然後在帝 晶體上採用研磨技術磨平，並鍍上鋁或銀等當作反射 鏡，形成CMOS基板，再將CM0S基板與含有透明電極 的玻璃基板貼全後灌入液晶分子並封裝測試，形成Lc〇s 面板。LCoS面板通過控制光的偏振狀態來調制入射光並 給入射光加入空間訊息，形成包括該入射光及該空間訊 息訊息經過調制之出射光。所述空間訊息可以為該LCoS 所載入之控制訊號電壓，該控制訊號電壓直接控制薄膜 電曰=體之開關狀態’再利用該薄膜電晶體來控制所述液 曰曰/刀子之偏轉狀態，而液晶分子具有明顯之光學各向異 性，忐夠控制來自入射光之光線，從而實現為入射光載 p 入圖像訊號之目的。在本實施例中，該反射式空間光調 益 2姆S偏振光進行調制並載入空間訊息，並將經 調制及载入有空間訊息之P偏振光反射出去，該P偏振 光透過偏振分束器121並發射出去。 所述偏器13可以為一偏光片，其可以讓一定偏振 方向之光通過，而吸收其他偏振方向之光。例如讓p偏 振光通過，而吸收s偏振光或者讓S偏振光通過，而吸 爲振光。在本實施例中，該檢偏5| 13吸收S偏振光 而讓P偏振光通過。 ° 11 200914876 所述穿透式光調制器14可以為液晶顯示裝置（Liquid Crystal Dispaly，LCD)。通過為該穿透式光調制器14輸入 脈衝訊號來控制該穿透式光調制器14之開啟與截止。如 圖3所示，為輸入穿透式光調制器14之輸入訊號以及相 對於左右眼輸出光之偏振狀態之波形圖。在本實施例 中，所述穿透式光調制器14按照圖3所示之輸入訊號波 形圖開啟或截止，從而交替為左右眼提供不同偏振方向 的S偏振光及P偏振光。當為該穿透式光調制器輸入該 訊號時，該穿透式光調制器14便可交替輸出S偏振光或 P偏振光以提供觀看者左右眼之不同偏振方向之光。可以 理解的是，該輸入訊號之週期係可以調整的。通過穿透 式光調制器14之開啟與截止可以控制所輸入偏振光之偏 振方向，在本實施例中，輸入穿透式光調制器14的係P 偏振光，下以P偏振光為例，來說明該穿透式光調制器 14的作用原理。當然，可以想到的是，對S偏振光之作 用係與P偏振光相同。 在該穿透式光調制器14開啟時，如圖1所示，該P 偏振光直接穿過該穿透式光調制器14而不會對該P偏振 光之偏振狀態進行調制。但是，在穿透式光調制器14截 止時，如圖2所示，就會對穿過之P偏振光進行調制， 即把輸入之P偏振光調制為S偏振光輸出，從而可以交 替地為觀看者提供左右眼之不同偏振方向之光。 所述投影鏡頭15設置於穿透式光調制器14之出射光 之光路上，用於將出射光所形成之圖像放大，並將放大 12 200914876 之圖像投影到螢幕（圖未示）上。 圖4為本發明提供之第二實施例之立體投影光學系 統200之結構示意圖。該立體投影光學系統200包括沿 光路方向依次設置之一光源元件21、一圖像吸收器22， 一設置於所述圖像吸收器22之一條出射光路上之檢偏器 23、一設置於所述檢偏器23出射光路上之穿透式光調制 器24以及一投影鏡頭25。 該第二實施例與第一實施例之不同在於所述圖像吸 收器22之組成結構不同，第二實施例之圖像吸收器22 包括一偏振分束器221及一穿透式空間光調制器222。該 穿透式空間光調制器222可以為液晶顯示裝置（Liquid Crystal Dispaly，LCD)。所述穿透式空間光調制器222通 過控制輸入光之偏振狀態來調制入射光並給入射光加入 空間訊息，形成包括該空間訊息之經過調制之出射光。 所述空間訊息可以為所述穿透式空間光調制器222所載 入的控制訊號電壓，該控制訊號電壓直接控制薄膜電晶 體之開關狀態，再利用該薄膜電晶體來控制所述液晶分 子之偏轉狀態，而液晶分子具有明顯之光學各向異性， 能夠控制來自入射光之光線，從而實現為入射光載入圖 像訊號之目的。在本實施例中，該所述穿透式空間光調 制器222對入射之S偏振光進行調制，並在所述S偏振 光上疊加空間訊息，以產生一包括空間訊息之出射光， 即包括有空間訊息之P偏振光。該P偏振光穿過該穿透 式空間光調制器222後發射出去。 13 200914876 因所述檢偏器23可以讓一定偏振方向之光通過，而 吸收其他偏振方向之光。例如讓P偏振光通過，而吸收s 偏振光或者讓S偏振光通過，而吸收P偏振光。所以當 該檢偏器23讓P偏振光通過，而吸收S偏振光時，該檢 偏器23設置在穿透式空間光調制器222之S偏振光之出 射光路上。t該檢偏器23讓s偏振光通過，而 振光時:錢^ 23設置在穿透式"光㈣器== 射光路上。在本實施例中，該檢偏器13設 上。而該光調制器222之S偏振光之出射光路 光調制器24 S偏振光在其他光學元件如穿透式 、、 〒之傳輪光路相同。 制器輸ί i:: „統使用時可通過為穿透式光調 個交替之工作:該牙透式光調制器具有開啟及截止兩 同偏振狀’使传觀看者之左、右眼交替獲得不 看者之左右目/ #該輪人訊號之頻枝夠快時，觀 片，就可以=職上檢偏方向相互垂直之兩片偏振 置之檢偏器， 圖像吼息。同時利用光路上設 之光通過而分該檢偏&之作用下，允許特定偏振方向 徵所導致之圖且排除了由實光學元件所固有之光學特 件材料中之雙折雜/以及由所述偏振光光路中之光學元 所投影之出二丄射所產生之雜亂空間訊息，從而提昇了 綜上所先之對比度。 專利申請。惟\合發料利要件，：!；依法提出 ' 述者僅為本發明之較佳實施方式， 200914876 本發明之範圍並不以上述實施方式為限，舉凡熟悉本案 技藝之人士援依本發明之精神所作之等效修飾或變化， 皆應涵蓋於以下申請專利範圍内。 【圖式簡單說明】 圖1係本發明第一實施例之立體投影光學系統在所 述穿透式光調制器開啟時之結構示意圖。 圖2係本發明第一實施例之立體投影光學系統在所 述穿透式光調制器截止時之結構示意圖。 圖3係圖1的所述穿透式光調制器之輸入訊號以及 相對於左右眼輸出之光之偏振狀態之波形圖。 圖4係本發明提供之第二實施例之立體投影光學系 統之結構不意圖。 【主要元件符號說明】 立體投影光學糸統 100 、 200 光源組件 11、21 照明光源 111 色輪 112 積分器 113 圖像吸收器 12>22 偏振分束器 121 、 221 檢偏裔 13、23 穿透式光調制器 14、24 投影鏡頭 15、25 反射式空間光調制器 122 、 222 15200914876 IX. Description of the invention: [Technical field to which the invention pertains] The present invention relates to a projection optical system, and more particularly to a stereoscopic projection optical system having high contrast. [Prior Art] In recent years, image projectors, especially digital projectors, have become popular as tools for displaying plural messages to viewers. Typically, these projectors are used to project a computer-generated image onto a screen. For the viewer, the image projected by the image projector usually looks like a flat two-dimensional image, and no image depth of field information can be displayed except the image itself. This display can be used to display complex messages. However, in some cases, the viewer desires to have a projector that can display the depth of field or structural features of the image to a greater extent than the two-dimensional display. One way to enable an image of a two-dimensional display to give an image depth of field is to display the image stereoscopically. Stereoscopic images, often referred to as "three-dimensional" or "3D" images, have a depth dimension to the viewer. These image packs include separate, superimposed left and right eye images that are set to mimic the small differences in the surface of the three-dimensional object caused by the separation of the human eye when viewed from the left and right eyes of the person. image. The left eye and right eye images are displayed such that the viewer's right eye does not see the left eye image. The left eye does not see the right eye image. This type of display is generally by means of an optical filter worn by the viewer. A typical stereoscopic projection optical system includes a polarization beam splitter for splitting incident light into different polarization directions and a left image generation element for generating a left eye image and a right eye image by different polarizations of 200914876 and The right image produces components. By projecting the left and right eye images generated by the left and right image generating elements onto the screen, stereoscopic images can be seen when the left and right eyes of the person wear glasses of different polarization directions. However, when the light is emitted from the polarizing beam splitter, the emitted light contains disordered light, and the presence of the disordered light is partly due to image noise caused by the optical characteristics inherent in all the real optical components, such as polarization. When a beamer receives a high level of luminous flux, it generally becomes a thermal load and occurs: physical distortion causes stress birefringence, which causes depolarization of light and a decrease in contrast, and for some reason the polarized light Receiving spatial information on the respective left and right image generating elements, respectively, and receiving the chaotic space generated by the birefringence in the optical material of the polarized light path, such as a polarizing beam splitter. The message 'and these messy lights are not effectively separating and eliminating their noise before being projected onto the display, these image noise and cluttered spatial information will reduce the contrast of the projected light projected onto the screen. SUMMARY OF THE INVENTION In view of the above, it is necessary to provide a stereoscopic projection optical system capable of improving contrast. A stereoscopic projection optical system comprising: an image absorber for receiving incident light, modulating the incident light and loading a spatial message, and emitting a modulated polarization and loading a polarization direction of the spatial information a first polarized light and a second polarized light; an analyzer disposed on the exiting light path of the first polarizer 8 200914876 emitted by the image absorber for passing light of a specific polarization direction; a transmissive optical modulator disposed on an outgoing optical path of the first polarized light emitted by the analyzer, the transmissive optical modulator having two alternating working states of opening and closing, the transmissive optical modulation When the device is in an on state, the first polarized light passes through the transmissive light modulator, and when the transmissive light modulator is in an off state, the penetrating light modulator will be incident on the first The polarized light is modulated into a second polarized light and emitted. The stereoscopic projection optical system can be used to input signals for the transmissive optical modulator, so that the transmissive optical modulator has two alternating working states of opening and closing, so that the left and right eyes of the viewer alternately obtain different signals. In the image of the polarization state, when the frequency of the input signal is fast enough, the left and right eyes of the viewer respectively wear two polarizing plates whose detection directions are perpendicular to each other, and the stereoscopic image information can be observed. At the same time, the analyzer disposed on the light path of the Ricoh allows the light of a specific polarization direction to pass through and separates and excludes the image noise caused by the optical characteristics inherent in the real optical component. The chaotic spatial information generated by the birefringence in the optical element material in the polarized light path enhances the contrast of the projected outgoing light. [Embodiment] Hereinafter, the following preferred embodiments will be described in detail with reference to the accompanying drawings. 1 and 2 are schematic structural views of a stereo projection optical system 100 according to a first embodiment of the present invention. The stereoscopic projection optical system 100 includes one light source element 11 disposed in the optical path direction, a FIG. 9 200914876 image absorber 12, a detection offset H 13 disposed on one of the image absorbers i2, and is disposed on The analyzer 13 emits the transmissive light modulator 14 on the optical path and a projection lens 15. The light source element 11 includes an illumination source 111 & wheel_112 and an integrator 113 arranged in accordance with the optical path. The illumination source emits red light (R), green light (g), and blue white light required to display color. ^The light source U can be a sinus lamp, a metallization lamp, a xenon lamp or an LED. In this embodiment, the light source u is a south lamp. ^ = 'includes red, green, and blue three-color zones, which can be rotated at the speed of the motor (the π motion of the figure to match the projection light path with various colors. The integral i§ m is used to homogenize and effectively The light emitted by the light source u = the image absorber 12 includes a polarization beam splitter 121 disposed along the optical path and a reflective spatial light modulator 122. The polarization beam splitter (PBS) m is used. The unpolarized light from the light source element 11 is converted into a first polarized light and a second polarized light. In the actual target example, the first polarized light is s-polarized light, and the second polarized light is P-polarized light. The polarizing beam splitter 121 is reflected by the polarization beam splitter 121, and the p-polarized light beam is transmitted through the polarization beam splitter 121. The polarization beam splitter 121 can be a metal grid polarizer (Wire Grid Polarizer, or a WGP polarizer or a polarization beam splitting prism). In the present embodiment, the polarization beam splitter ΐ2ι is a polarization beam splitting prism. The polarization beam splitter 111 can be divided into reflective S-polarized light and transmitted through p-polarized light according to different effects on 8-polarized light and p-polarized light. Reflecting P-polarized light through S-polarized light In this embodiment, the polarizing beam splitter 23 reflects S-polarized light, and can transmit 200914876 p-polarized light. The reflective spatial light modulator 122 can be Liquid Crystal on Silicon (LCoS). Display panel. The Shihki liquid helium display panel process structure combines liquid crystal technology and semiconductor integrated circuit technology. The LCoS panel uses a semiconductor process to fabricate the driving panel, and then is ground on the crystal of the emperor crystal and plated with aluminum or Silver is used as a mirror to form a CMOS substrate, and the CMOS substrate and the glass substrate containing the transparent electrode are attached to the liquid crystal molecules and packaged and tested to form an Lc〇s panel. The LCoS panel modulates the incident by controlling the polarization state of the light. And adding a spatial message to the incident light to form an outgoing light including the incident light and the spatial information message. The spatial information may be a control signal voltage loaded by the LCoS, and the control signal voltage directly controls the thin film power = switch state of the body 'reuse the thin film transistor to control the deflection state of the liquid helium/knife, and the liquid crystal molecule has Obvious optical anisotropy, which can control the light from the incident light, thereby achieving the purpose of inputting the image signal into the incident light. In this embodiment, the reflective spatial light is modulated by 2 S-polarized light for modulation. And loading the spatial information, and reflecting the P-polarized light modulated and loaded with the spatial information, the P-polarized light is transmitted through the polarizing beam splitter 121 and emitted. The polarizer 13 may be a polarizer, which may Let light of a certain polarization direction pass, and absorb light of other polarization directions. For example, let p-polarized light pass, absorb s-polarized light or let S-polarized light pass, and absorb into vibrating light. In the present embodiment, the detection bias 5|13 absorbs the S-polarized light and allows the P-polarized light to pass. ° 11 200914876 The transmissive light modulator 14 can be a liquid crystal display device (LCD). The turn-on and turn-off of the transmissive light modulator 14 is controlled by inputting a pulse signal to the transmissive light modulator 14. As shown in Fig. 3, it is a waveform diagram of the input signal input to the transmissive optical modulator 14 and the polarization state of the output light with respect to the left and right eyes. In the present embodiment, the transmissive light modulator 14 is turned on or off according to the input signal waveform pattern shown in Fig. 3, thereby alternately providing S-polarized light and P-polarized light of different polarization directions for the left and right eyes. When the signal is input to the transmissive light modulator, the transmissive light modulator 14 alternately outputs S-polarized or P-polarized light to provide light of different polarization directions of the left and right eyes of the viewer. It can be understood that the period of the input signal can be adjusted. The polarization direction of the input polarized light can be controlled by the turn-on and turn-off of the transmissive light modulator 14. In the present embodiment, the P-polarized light of the transmissive light modulator 14 is input, and the P-polarized light is taken as an example. The principle of operation of the transmissive light modulator 14 will be described. Of course, it is conceivable that the effect on S-polarized light is the same as that of P-polarized light. When the transmissive light modulator 14 is turned on, as shown in Fig. 1, the P-polarized light passes directly through the transmissive light modulator 14 without modulating the polarization state of the P-polarized light. However, when the transmissive optical modulator 14 is turned off, as shown in FIG. 2, the P-polarized light that passes through is modulated, that is, the input P-polarized light is modulated into an S-polarized light output, so that it can be alternately The viewer provides light of different polarization directions for the left and right eyes. The projection lens 15 is disposed on the optical path of the outgoing light of the transmissive light modulator 14 for amplifying the image formed by the emitted light, and projecting the image of the enlarged 12 200914876 onto a screen (not shown) . 4 is a schematic structural view of a stereoscopic projection optical system 200 according to a second embodiment of the present invention. The stereoscopic projection optical system 200 includes a light source component 21, an image absorber 22, an analyzer 23 disposed on one of the image exiters 22, and an optical detector 22 disposed in the optical path. The transmissive optical modulator 24 and a projection lens 25 on the optical path are detected by the analyzer 23. The second embodiment differs from the first embodiment in that the image absorber 22 is different in composition. The image absorber 22 of the second embodiment includes a polarization beam splitter 221 and a transmissive spatial light modulation. 222. The transmissive spatial light modulator 222 can be a liquid crystal display (LCD). The transmissive spatial light modulator 222 modulates the incident light by controlling the polarization state of the input light and adds spatial information to the incident light to form modulated modulated light including the spatial information. The spatial information may be a control signal voltage loaded by the transmissive spatial light modulator 222, the control signal voltage directly controls a switching state of the thin film transistor, and the thin film transistor is used to control the liquid crystal molecules. The deflection state, while the liquid crystal molecules have obvious optical anisotropy, can control the light from the incident light, thereby achieving the purpose of loading the image signal into the incident light. In this embodiment, the transmissive spatial light modulator 222 modulates incident S-polarized light and superimposes spatial information on the S-polarized light to generate an outgoing light including a spatial message, that is, includes P-polarized light with spatial information. The P-polarized light is transmitted through the transmissive spatial light modulator 222 and emitted. 13 200914876 The analyzer 23 can pass light of a certain polarization direction and absorb light of other polarization directions. For example, P-polarized light is passed, and s-polarized light is absorbed or S-polarized light is passed, and P-polarized light is absorbed. Therefore, when the analyzer 23 passes the P-polarized light and absorbs the S-polarized light, the analyzer 23 is disposed on the outgoing light path of the S-polarized light of the transmissive spatial light modulator 222. t The analyzer 23 allows the s-polarized light to pass, and when oscillating: the money ^ 23 is set on the transmissive "light(4) device== illuminating path. In the present embodiment, the analyzer 13 is provided. The S-polarized light of the light modulator 222 is the same as the optical path of the other optical elements, such as the transmissive and the transmissive.输 i:: „ can be used to alternate the work for the transmissive light: the tooth-operated light modulator has the same polarization as the opening and closing, so that the left and right eyes of the viewer are alternated. Obtaining the left and right eyes of the unobserved person / # When the frequency of the round signal is fast enough, the film can be used as the analyzer with two polarizations perpendicular to each other and the image is suffocated. The light passing through the optical path passes through the detection of the bias & the image caused by the specific polarization direction sign and excludes the double-fold in the optical component material inherent to the real optical component and The interfering spatial information generated by the two-projection projected by the optical element in the polarized light path enhances the contrast of the first one. Patent application. Only the appropriate requirements, :!; The present invention is not limited to the above-described embodiments, and equivalent modifications or variations made by those skilled in the art in light of the spirit of the present invention should be included in the following applications. Within the scope of the patent. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view showing the structure of a stereoscopic projection optical system according to a first embodiment of the present invention when the transmissive optical modulator is turned on. FIG. 2 is a perspective view of the stereoscopic projection optical system according to the first embodiment of the present invention. FIG. 3 is a waveform diagram of the input signal of the transmissive optical modulator of FIG. 1 and the polarization state of the light outputted from the left and right eyes. FIG. 4 is a waveform diagram of the present invention. The structure of the stereoscopic projection optical system of the second embodiment is not intended. [Description of main component symbols] Stereoscopic projection optical system 100, 200 Light source assembly 11, 21 Illumination light source 111 Color wheel 112 Integrator 113 Image absorber 12> 22 Polarization Beamsplitters 121, 221 Detectives 13, 23 Transmissive Light Modulators 14, 24 Projection Lenses 15, 25 Reflective Spatial Light Modulators 122, 222 15