200912381 九、發明說明： 【發明所屬之技術領域】 本發明關於-種投影光學系統，尤其係—種具有立 體投影顯示功能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 讀示多種訊息之工具已經逐漸流行。—般，這些投聲 ί用於將由電腦生成之圖像投影到螢幕上。對觀看者來 =圖像才又衫儀投影之圖像通常看起來係平面二維圖 像’除圖像本身外紐顯示任何圖像景深 : = 顯示多種訊息。但是，在某些情況“ 、、果有比—維顯不能夠更大程度地顯示圖像之景 冰或結構特徵之投影儀。 維顯示之圖像能給出圖像景深之—種方式係通 過立體地顯示圖像。立體圖像，通常稱為“三維，，或 «像’在鮮者看來具有較 括分開的、疊人的m ^ 且口的左眼及右眼圖像，這些圖像設置成模 之左右眼觀麵，由於人眼睛間隔引起之三維物體 係這==別’具有之景深圖像。左眼及右眼圖像 看不到切不’即觀看者之右眼看不到左眼圖像，左眼 之光學濾、=像。這種顯示方式—般借助於觀看者佩戴 影系方式係使用兩個分開之圖像投 技衫左眼圖像及右眼圖像。而這種系統在 200912381 成功地用於形成立體圖像之同時，系統之成本和重量則 比單個投景>儀要高很多。而且，兩個投影儀要求光學對 準相對困難並比較費時。還有，由於這兩個系統之重量 及體積，使這種系統在兩個位置之間移動起來特別困 難，還有存在潛在之圖像對準之問題。 【發明内容】 有鑒於此，有必要提供一種單個的能夠投影立體 的立體投影光學系統。 豕 一種立體投影光學系統，其包括： f偏振分束器’該第—偏振分束器用於將入射光 刀成—偏振方向垂直之第一偏振光及第二偏振光； 之第設置於所述第一偏振分束器出射 _射光路上，該穿透式光調制器具有開 啟及截止兩個交替的 ’、百開 開啟狀態時，所_ 丨牙透式光調制器處於 器，該穿透―光調制 :制器將人射之所述第-偏振光_第==: 固诼吸收器，該圖像吸九 制器之出射光路上，其包括—^7 ;料穿透式光 反射式空間光調制器 振分束器及-第. 所、十、笛 及弟一反射式空間光碉告丨哭， 所述第—偏振分 ]九益， 啟狀態之穿透式光 、 偏振光穿過所述月 在弟-反射式空間光調制器上，束器後照4 °亥弟™反射式空間光言j 200912381 制器將該第一偏振光調制成第二偏振光反射出去，調制 後反射之該第二偏振光經過第二偏振分束器後發射出 去； 所述第一偏振分束器出射之第一偏振光入射到所述 截止狀態之穿透式光調制器，並經該穿透式光調制器將 該弟·一偏振光调制成弟·一偏振光後出射5调制後出射之 該第二偏振光經過第二偏振分束器後照射在第二反射式 空間光調制器上，該第二反射式空間光調制器將該第二 偏振光調制成第一偏振光反射出去，該調制後反射之第 一偏振光經過第二偏振分束器後發射出去。 上述之立體投影光學系統使用時可通過為穿透式光 調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。 【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，為本發明所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 第一偏振分束器12, 一設置於所述第一偏振分束器12 之一條出射光路上之穿透式光調制器13，一設置於穿透 9 200912381 式光凋制器13出射光路上之圖像吸收器14,以及一設置 於圖像吸收器14出射光路上之投影鏡頭15。 所述光源元件n包括依光路設置的一照明光源 、—色輪112以及一積分器n3。所述照明光源U1 發射包括顯轉色®像所需之紅細)、綠光(G)及藍光⑻ =白光。該光源11可以為鹵素燈、金屬鹵化物燈或氙燈 々 本貝施例中，該光源11為鹵素燈。所述色輪112 G括紅、綠、監三色區，其可在電機（圖未示）之帶動下高 逮方疋轉，以給投影光路配以各種色彩。所述積分器113 用來均句化及有效地使用光源11發出之光。 L 弟偏振刀束态（P〇larizati〇n Beam Splitter，PBS) 12,用於將來自光源元件u之非偏振光變成第—偏振光 ，第二偏振在本實施例中所第-偏振光為S偏振光， ^-偏振光為P偏振^該s偏振光被該第—偏振分束 器12反射r^P偏振光透過該第一偏振分束器n該第 -偏振分束器可以為金屬柵格型偏振片(衞二 Polarizer’簡稱WGP偏振片），也 在本實施^第―偏振分束器12:;= 所述牙透式光調制器13可以設置於所述第— 束器12之S偏振光之出射光路上，也可以設置於所= :偏== 之P偏振光之出射光路上’可以想到的 疋La置方法之立體投影絲系統之結構及 原理是基本相_。在本實_.中，該穿透式光調制号 13設置於所衫-偏振分束器12之？偏振光之出射光路 200912381 上。該穿透式光調制器13可以為液晶顯示裝置（Liquid Crystal Dispaly，LCD)。通過為該穿透式光調制器13輸入 脈衝訊號來控制該穿透式光調制器13之開啟與截止。如 圖3所示，為輸入穿透式光調制器13之輸入訊號以及相 對於左右眼輸出光之偏振狀悲之波形圖。在本實施例 中，所述穿透式光調制器13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 之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13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13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13之光為 P偏振光，下以P偏振光為例，來說明該穿透式光調制 器13之作用原理。當然，可以想到的是，對S偏振光之 作用係與P偏振考相同的。 在該穿透式光調制器13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13而不會對該P偏振 光的偏振狀態進行調制。但是，在穿透式光調制器13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。 所述圖像吸收器14設置於所述穿透式光調制器13之 出射光路上。該圖像吸收器14包括一第二偏振分束器 11 200912381 141以第〜、楚 所述第二偏反射式空間㈣制器142、⑷各—個。 侷振分束器141與第—偏 工作原理基本相同，在此不再賢述。該第 141在所切透式光調網13開㈣，如圖丨所示，二 收之入射光為P偏振光，在穿透式光調制器13截止時， 如圖2所示，接收之人射光為s偏振光。所述第—、第 二反射式空間光調制器142、143之結構及工作原理基本 相同’下面以第-f透式光調制器、143 ^例來說明其結 構及工作原理。 〃 σ 所述第一反射式空間光調制器143可以為矽基液晶 (Liquid Crystal on Silicon，LCoS)顯示面板。該矽基液晶200912381 IX. Description of the Invention: [Technical Field] The present invention relates to a projection optical system, and more particularly to a stereoscopic projection optical system having a stereoscopic projection display function. /, [Prior Art] In recent years, 'image projectors', especially digital projectors, have become popular as tools for viewing a variety of messages. Typically, these sounds are used to project a computer-generated image onto the screen. The image that is projected to the viewer = image is usually a flat 2D image. In addition to the image itself, any image depth of field is displayed: = Display multiple messages. However, in some cases, ", there is a ratio of - the display can not display the image of the ice or structural features of the image to a greater extent. The image of the dimensional display can give the image depth of field - the way By stereoscopically displaying images. Stereoscopic images, often referred to as "three-dimensional, or «images", in the eyes of the fresher, have a more separate, overlapping m^ and mouth of the left and right eye images. The image is set to the left and right eye view of the model, due to the three-dimensional object system caused by the human eye interval, which has a depth of field image. The image of the left eye and the right eye cannot be seen. That is, the right eye of the viewer cannot see the image of the left eye, and the optical filter of the left eye, = image. This type of display generally uses two separate image caster left eye images and right eye images by means of the viewer wearing the film system. While this system was successfully used to form stereoscopic images in 200912381, the cost and weight of the system was much higher than that of a single projection. Moreover, the two projectors require optical alignment to be relatively difficult and time consuming. Also, due to the weight and volume of the two systems, it is particularly difficult to move the system between two positions, and there is a potential for image alignment. SUMMARY OF THE INVENTION In view of the above, it is necessary to provide a single stereoscopic projection optical system capable of projecting a stereo. A stereoscopic projection optical system, comprising: an f-polarization beam splitter', wherein the first polarization beam splitter is configured to set the incident light into a first polarization and a second polarization that are perpendicular to a polarization direction; A polarizing beam splitter exits the illuminating path, the transmissive optical modulator has two alternating 'on and off' states, and the 丨 透 透 光 光 , , , , , , , Modulation: the device emits the first-polarized light_第==: a solid-state absorber, the image is taken on the exit light path of the nine-device, which includes -^7; material-transmitting light-reflecting space The light modulator vibrating beam splitter and the -, the ten, the flute and the younger one reflect the spatial light to scream, the first - polarization sub-nine, the open state of the penetrating light, the polarized light passes through The month is on the dich-reflective spatial light modulator, and the beam is rear-illuminated by the 4°HideTM reflective spatial light j 200912381. The first polarized light is modulated into the second polarized light and reflected. The second polarized light that is reflected is emitted after passing through the second polarizing beam splitter; The first polarized light emitted from the beam splitter is incident on the cut-off light modulator in the off state, and the translucent light modulator is used to modulate the polarized light into a polarized light and then emit 5 modulation. The second polarized light that is emitted after passing through the second polarizing beam splitter is irradiated on the second reflective spatial light modulator, and the second reflective spatial light modulator modulates the second polarized light into the first polarized light. Reflected, the modulated first reflected light is transmitted through the second polarizing beam splitter. The stereoscopic projection optical system described above can be used to input signals to the transmissive optical modulator such 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 polarizations. In the image of the 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. [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 stereoscopic projection optical system 100 according to a first embodiment of the present invention. The stereoscopic projection optical system 100 includes a light source element 11 and a first polarization beam splitter 12 disposed in the optical path direction, and a transmissive light modulation disposed on one of the first polarization beam splitters 12 The image sensor 13 is disposed on the image absorber 14 which penetrates the exiting light path of the 200912381 type light beam eliminator 13, and a projection lens 15 disposed on the outgoing light path of the image absorber 14. The light source element n includes an illumination source, a color wheel 112, and an integrator n3 disposed along the optical path. The illumination source U1 emits red, green (G) and blue (8) = white light, which are required to display a color image. The light source 11 can be a halogen lamp, a metal halide lamp or a xenon lamp. In the embodiment of the present invention, the light source 11 is a halogen lamp. The color wheel 112G includes red, green and super-color zones, which can be rotated by a motor (not shown) to match the projection light path with various colors. The integrator 113 is used to uniformly and effectively use the light emitted by the light source 11. L 偏振 polarizing knife beam state (PBS) 12 for converting unpolarized light from the light source element u into first-polarized light, and the second polarization is in the present embodiment S-polarized light, ^-polarized light is P-polarized ^the s-polarized light is reflected by the first-polarizing beam splitter 12, and the polarized light is transmitted through the first polarizing beam splitter n. The first-polarizing beam splitter can be metal A grid type polarizer (Wilomerizer referred to as a WGP polarizer) is also used in the present embodiment - a polarization beam splitter 12:; = the toothed light modulator 13 can be disposed in the beamplitter 12 The outgoing light path of the S-polarized light may be set on the outgoing light path of the P-polarized light of the ====== The structure and principle of the stereoscopic projection silk system in which the 疋La method is conceivable is the basic phase. In the present embodiment, the transmissive light modulation number 13 is disposed in the shirt-polarization beam splitter 12? The outgoing light path of polarized light is on 200912381. The transmissive light modulator 13 can be a liquid crystal display device (LCD). The turn-on and turn-off of the transmissive optical modulator 13 is controlled by inputting a pulse signal to the transmissive optical modulator 13. As shown in Fig. 3, the input signal of the input transmissive optical modulator 13 and the waveform of the polarization of the output light with respect to the left and right eyes are shown. In the present embodiment, the transmissive light modulator 13 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 optical modulator, the transmissive optical modulator 13 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 opening and closing of the transmissive light modulator 13. In the present embodiment, the light input to the transmissive light modulator 13 is P-polarized light, and the P-polarized light is taken as an example. The principle of operation of the transmissive optical modulator 13 will be described. Of course, it is conceivable that the effect on S-polarized light is the same as that of P-polarization. When the transmissive optical modulator 13 is turned on, as shown in Fig. 1, the P-polarized light passes directly through the transmissive optical modulator 13 without modulating the polarization state of the P-polarized light. However, when the transmissive optical modulator 13 is turned off, as shown in FIG. 2, the P-polarized light passing therethrough 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 image absorber 14 is disposed on the outgoing light path of the transmissive light modulator 13. The image absorber 14 includes a second polarization beam splitter 11 200912381 141, each of which is a second partial reflection type space (four) device 142, (4). The local vibration beam splitter 141 is basically the same as the first-bias working principle and will not be described here. The 141th is opened in the cut-through optical network 13 (four), as shown in FIG. 2, the incident light is P-polarized light, and when the transmissive optical modulator 13 is turned off, as shown in FIG. The human light is s-polarized. The structures and operating principles of the first and second reflective spatial light modulators 142, 143 are substantially the same. The structure and operation principle of the first-f transparent optical modulator are described below. σ σ The first reflective spatial light modulator 143 may be a liquid crystal on silicon (LCoS) display panel.矽-based liquid crystal
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，然後在電 晶體上採用研磨技術磨平，並鐘上鋁或銀等當作反射 鏡，形成CMOS基板，再將CMOS基板與含有透明電極 的玻璃基板貼全彳象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sfl息，形成包括該入射光及該空間訊 息之經過調制之出射光。所述空間訊息可以為該[Cos 所載入之控制訊號電壓，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，從而實現為入射光载 入圖像訊號之目的。在本實施例中，當穿透式光調制器 12 200912381 13開啟時’如圖1所示’該第一反射 對該P偏振光進行調制，並在所述p偏振态142 訊息，以產生-包括空間訊息之出射光二空間 訊息之s偏振光。its偏振光被第_ 2二間 器142反射並經第二偏振分束n⑷發射出;去先調制 當穿透式光調制器13截止時，如圖2心1 ;:射==!143對入射之所述s偏振光進行 调制，並在所述S偏振光上疊加空間訊息，以丁 持空間訊息之出射光，即包括有空間訊息之P偏 ^ fP偏振光被第二反射式空間光調制器143發射並办读 第二偏振分束器141後發射出去。 牙 光鏡頭15設置於第二偏振分束器141之出射 ί ί路上，用於將出射光所形成之圖像放大，並將放 大之圖像投影到螢幕上。 將放 可以理解的是，為了進—步提高系 :在上述之立體投影光學系統中加入—偏振 吸收其他讓—定偏振方向之光通過，而 、他侷振方向之光，例如讓ρ 偏振光或麵S偏振光通過，通過，而吸收s 片16之具體之放置位置可以為第先。該偏振 透式光調制哭々 為弟一偏振分束器12與穿 在第1振:卜 之間之任意位置。在本實施例中 都設置有偏二片與穿透式光調制器13之光路之間 如圖5所示，綱式光物13之輸入訊號以及 13 200912381 與該輸入訊號相對應：交替為投射 偏振狀態之波形圖。當觀看者之力士、石艮之先之 向相互垂直之兩片偏振片時，例如又刀別戴上檢偏方 如’左眼戴上P偏# Η 而右眼戴上S偏振片，則左眼只可看到 、’ 只可看到S偏振光。根據人眼之視臀 "而右眼 個視像消失後’仍可使該物像在視網膜上：二:在某 秒左右 >，當穿透式光調制器13之# •一 0.4 於物像在視網膜上滯留之時間時，週期小 體之圖像。 °以看到立 請參閱圖6，為本發明提供之篦_告a 系統-之結構-意圖。該立體“玆= 沿光路方向依次設置的—光源元件21、—二’ 匕括 器22,一設置於所述第-偏振分束考帛偏振分束 上之穿透式光調制$ 23’-設置於穿 ^^光路 出射光路上之圖像吸收器24 ,以月—式先調制斋23 24出射光路上之投影鏡頭25。及—設置於圖像吸收器 同第-實施例，所述圖像吸收器24包 分束器2“及第-、第二反射式空 弟-偏振 各-個。該第二實施例與第— D。制為242、如 ―、第-偏振分束哭M、例之不同在於所述第 乐一偏振刀采态22、241對S偽担止n 作用不同。在本第二實 x先及P偏振光之 束器22、241反二;=中’f述第-、第二偏振分 偏振分束器。而該P偏振先:：:乂讓s偏振光透過各 第—偏振分束器22、μ … '"光在各光學元件即 #—、弟二反射式空間光調制器 14 200912381 242、243以及第二偏振分束器241中之傳輸光路係相同 的。 同理，為了進一步提高系統之對比度，還可以在第二 實施例之立體投影光學系統200中加入一個偏振片26， 其設置位置與第一實施例相同。 上述之立體投影光學系統使用時可通過為穿透式光 調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。 綜上所述，本發明符合發明專利要件，爰依法提出 專利申請。惟，以上所述者僅為本發明之較佳實施方式， 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_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係在圖1之立體投影光學系統設置有偏振片之 15 200912381 結構示意圖。 圖5係圖1之穿透式光調制器之輸入訊號以及與該 輸入訊號相對應之為左、右眼所投射之光之偏振狀態之 波形圖。 圖6係本發明提供之第二實施例之立體投影光學系 統之結構示意圖。 【主要元件符號說明】 立體投影光學系統 100、200光源組件 11、21 照明光源 111 色輪 112 積分器 113 投影鏡頭 15、25 偏振片 16、26 穿透式光調制器13、23 第一、第二偏振分束器 12、141、22、241 第一、第二反射空間光調制器142、143、242、243 16The display panel process structure combines liquid crystal technology with semiconductor integrated circuit technology. The LCoS panel uses a semiconductor process to fabricate the driver panel, and then grinds it on the transistor using a grinding technique, and uses aluminum or silver as a mirror to form a CMOS substrate, and then affixes the CMOS substrate to the glass substrate containing the transparent electrode. The liquid crystal molecules are poured and packaged to form an Lc〇s panel. The LCoS panel modulates the incident light by controlling the polarization state of the light and adds a spatial sfl to the incident light to form a modulated outgoing light comprising the incident light and the spatial information. The spatial information may be the control signal voltage loaded by the [Cos, the control signal voltage directly controls the switching state of the thin film transistor, and the thin film transistor is used to control the deflection state of the liquid crystal molecule, and the liquid crystal molecules have Obvious optical anisotropy, able to control the light from the incident light, so as to achieve the purpose of loading the image signal into the incident light. In the present embodiment, when the transmissive optical modulator 12 200912381 13 is turned on, 'the first reflection modulates the P-polarized light as shown in FIG. 1 and the information in the p-polarized state 142 to generate - Including the s-polarized light of the spatial information of the spatial information. Its polarized light is reflected by the _ 2 second 142 and transmitted by the second polarized beam splitting n(4); the first modulation is when the transmissive optical modulator 13 is turned off, as shown in Fig. 2; 1: ray ==! 143 pairs The incident s-polarized light is modulated, and a spatial information is superimposed on the S-polarized light to receive the outgoing light of the spatial information, that is, the P-polarized light including the spatial information is polarized by the second reflective spatial light. The modulator 143 emits and reads the second polarization beam splitter 141 and transmits it. The dental lens 15 is disposed on the exit ί ί of the second polarization beam splitter 141 for amplifying the image formed by the outgoing light and projecting the enlarged image onto the screen. It will be understood that in order to further improve the system: in the above-mentioned stereoscopic projection optical system, the polarization-absorbing light passing through other polarization directions is passed, and the light in the direction of the local oscillation is, for example, ρ-polarized light. Or the surface S-polarized light passes through, and the specific placement position of the absorption s-slice 16 can be first. The polarization-transparent light modulation is a position between the polarization beam splitter 12 and the first vibration: In the present embodiment, between the two paths and the optical path of the transmissive optical modulator 13, as shown in FIG. 5, the input signal of the optical element 13 and 13 200912381 correspond to the input signal: alternate projection Waveform of the polarization state. When the viewer's genius and sarcophagus lead to two polarizing plates that are perpendicular to each other, for example, the knives do not wear the eccentricity such as 'left eye wearing P bias # Η and right eye wearing S polarizing lens, then left The eye can only see, 'only visible S-polarized light. According to the eye of the human eye " and the right eye disappears after the 'still can make the object on the retina: two: around a second>, when the transmissive light modulator 13 # • a 0.4 The image of the periodic body when the object is stuck on the retina. °See the figure. Please refer to FIG. 6 for the structure-intention of the system provided by the present invention. The stereoscopic "Z = the light source element 21, the two's collimator 22 arranged in the direction of the optical path, and the transmissive light modulation $23' provided on the polarization beam splitting of the first polarization splitting beam An image absorber 24 disposed on the exiting optical path of the optical path, and a projection lens 25 on the exiting optical path of the modulating 23 24 is firstly modulated by the moon-type method. And being disposed in the image absorber and the first embodiment, the figure The image absorber 24 includes a beam splitter 2 "and a first-and a second-reflective mode--polarization". This second embodiment is the same as -D. The system is 242, such as ―, and the first polarization splitting is crying M. The difference is that the first and second polarization knives 22, 241 have different effects on S. In the present second and first P-polarized beam splitters 22, 241, the first and second polarization splitting beam splitters are described. And the P-polarization first:::乂 allows s-polarized light to pass through each of the first-polarization beam splitters 22, μ... '" light in each optical component, ie, #-, 弟二反射式 spatial light modulator 14 200912381 242, 243 And the transmission optical path in the second polarization beam splitter 241 is the same. Similarly, in order to further increase the contrast of the system, a polarizing plate 26 may be incorporated in the stereoscopic projection optical system 200 of the second embodiment, which is disposed at the same position as the first embodiment. The stereoscopic projection optical system described above can be used to input signals to the transmissive optical modulator such 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 polarizations. In the image of the 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. In summary, the present invention complies with the requirements of the invention patent, and proposes a patent application according to law. However, the above description is only the preferred embodiment of the present invention, and the scope of 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 are It should be covered in the following _ patent scope. 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 schematic view showing the structure of the stereoscopic projection optical system of the first embodiment of the present invention when the transmissive optical modulator is turned off. Fig. 3 is a waveform diagram showing the input signals of the transmissive optical modulator of Fig. 1 and the polarization states of the light outputted with respect to the left and right eyes. Fig. 4 is a schematic view showing the structure of a stereoscopic projection optical system of Fig. 1 provided with a polarizing plate 15 200912381. Figure 5 is a waveform diagram of the input signal of the penetrating optical modulator of Figure 1 and the polarization state of the light projected by the left and right eyes corresponding to the input signal. Fig. 6 is a schematic view showing the structure of a stereoscopic projection optical system according to a second embodiment of the present invention. [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 Projection lens 15, 25 Polarizer 16, 26 Transmissive light modulator 13, 23 First, Two polarization beam splitters 12, 141, 22, 241 First and second reflective spatial light modulators 142, 143, 242, 243 16