201024203 九、發明說明 【發明所屬之技術領域】 本發明係有關一種數位微鏡裝置（Digital Mirror Device ;簡稱DMD )。主要是爲了提供一種可使用簡易 的微機電系統（MEMS )製造步驟來製造之改良式裝置而 開發該 DMD。 【先前技術】 數位微鏡裝置（DMD )目前較慣常地運用於諸如簡報 型投影機（data projector)等的許多光學裝置中。在這些 裝置中，係以被配置在一半導體晶片（DMD )上的一矩陣 中之細微小鏡產生影像。每一鏡代表被投射影像中之一或 多個像素。鏡之數目對應於被投射影像之解析度。201024203 IX. Description of the Invention [Technical Field of the Invention] The present invention relates to a Digital Mirror Device (DMD). The DMD was developed primarily to provide an improved device that can be fabricated using simple microelectromechanical systems (MEMS) manufacturing steps. [Prior Art] A digital micromirror device (DMD) is currently used conventionally in many optical devices such as a data projector. In these devices, images are produced with fine mirrors arranged in a matrix on a semiconductor wafer (DMD). Each mirror represents one or more pixels in the projected image. The number of mirrors corresponds to the resolution of the projected image.
Texas Instruments 公司於 1 980 年代開發 DMD 技 Q 術（請參閱諸如 us 4,956,619、US 4,662,746、及相關的 專利）。 DMD晶片於其表面上設有被配置在一長方形陣列中 之對應於要被顯示的影像中之像素的數十萬個微鏡。可將 該等微鏡個別地旋轉 ± 1 0-1 2。至一打開或關閉狀態。在 - 該打開狀態中，來自投影機燈泡的光被反射到一鏡，而在 ' 螢幕上顯示亮的像素。在該關閉狀態中，光被引導到其他 位置（通常被引導到一散熱器），而顯示暗的像素。 爲了產生灰階，極迅速地打開及關閉該鏡，且打開時 -5- 201024203 間與關閉時間間之比率決定了所產生的明暗（二進位脈寬 調變）。現有的 DMD晶片可產生多達 1024個灰階。 係由鋁製造該等鏡本身，且該等鏡通常是 16微米 的正方形。每一鏡經由自該鏡的下表面延伸的一堅固柄而 被安裝在一軛上。一順應的扭轉鉸鏈支承該軛，而該扭轉 . 鉸鏈可使該軛（及連帶的該鏡）在其打開與關閉位置之間 移動。該等扭轉鉸鏈對機械疲乏及振動衝擊有較大的抗力 一些電極以靜電吸引/排斥控制鏡之位置。一對電極 被定位在該鉸鏈的每一側，其中一電極對該軛起作用，且 另一電極對該鋁鏡直接起作用。大約 20 - 30伏特的一 偏壓電位被施加到該鏡及軛，同時使用 5伏特的 CMOS 定址到該等電極。因此，當將該鏡一側上的電極被驅動到 + 5伏特時，該鏡朝向電極被驅動到 0伏特的相反側傾 斜。將該等 CMOS電壓反接時，將使該鏡朝向另一側傾 斜。因此，可經由該 CMOS而控制每一鏡的打開/關閉狀 @ 態。 若要得知對諸如前文所述的那些 DMD等的 DMD 之更詳細的說明，請參閱 David Armitage 等人所著的 “Introduction to Microdisplays’’（由 John Wiley and Sons 於 2006年出版）。 - 在過去大約十年中，對 DMD 的設計較無改變。然 · 而，這類較複雜的設計以及每一鏡總成中之數個移動零件 需要有對應複雜的微機電系統（MEMS )製程。此種複雜 -6- 201024203 性提高了製造成本，且可能影響到每一鏡總成可被微縮的 程度。最好是可提供一種具有比習知的 DMD簡單的設 計之 DMD。 . 【發明內容】 在一第一觀點中，提供了一種數位微鏡裝置，該數位 微鏡裝置包含被定位在一基材上的一陣列之微鏡總成，每 φ 一微鏡總成包含： 與該基材間隔開之一鏡，該鏡具有一上反射表面及一 下支承表面； 支承該鏡之一柄，該柄自該基材延伸到該下支承表面 ，該柄界定該鏡之一傾斜軸； 一第一電極及一第二電極，該第一及第二電極被定位 在該柄之每一側上，可經由該基材內之電子電路而個別地 定址到每一電極， φ 其中係由彈性可撓材料構成該柄，因而藉由一靜電力可使 該鏡朝向該第一電極或朝向第二電極傾斜。 因爲該鏡依著該可撓柄而傾斜，所以本發明不需要傳 統 DMD 中之軛及扭轉鉸鏈配置。此種方式大幅簡化了 DMD的整體設計及其製造。 ' 或可由諸如聚二甲基砂氧燒（polydimethylsiloxane ; 簡稱 PDMS )等的聚合物構成該柄。PDMS 具有較低的 楊氏模數（Young's modulus)(小於 1000 MPa (百萬巴 ))，因而可經由該一或多個電極施加的靜電力而彎曲該 201024203 柄。此外，本案申請人先前已證明 PDMS在微機電系統 (MEMS )中之效用、及其易於被加入微機電系統（ MEMS )製程中。Texas Instruments developed DMD technology in the 1980s (see, for example, us 4,956,619, US 4,662,746, and related patents). The DMD wafer is provided on its surface with hundreds of thousands of micromirrors arranged in a rectangular array corresponding to pixels in the image to be displayed. The micromirrors can be individually rotated by ± 1 0-1 2 . Up to the open or closed state. In - the open state, light from the projector's bulb is reflected to a mirror, and bright pixels are displayed on the 'screen. In this off state, light is directed to other locations (usually directed to a heat sink), while dark pixels are displayed. In order to generate gray scales, the mirror is turned on and off very quickly, and the ratio between -5 - 201024203 and off time when turned on determines the brightness (binary pulse width modulation) produced. Existing DMD wafers can produce up to 1024 gray levels. The mirrors themselves are made of aluminum, and the mirrors are typically squares of 16 microns. Each mirror is mounted on a yoke via a solid shank extending from the lower surface of the mirror. A compliant torsion hinge supports the yoke and the twist. The hinge moves the yoke (and the associated mirror) between its open and closed positions. These torsional hinges have a greater resistance to mechanical fatigue and vibrational shocks. Some electrodes attract/repeat the position of the mirror with static electricity. A pair of electrodes are positioned on each side of the hinge, with one electrode acting on the yoke and the other electrode acting directly on the aluminum mirror. A bias potential of approximately 20 - 30 volts is applied to the mirror and yoke while being addressed to the electrodes using a 5 volt CMOS. Therefore, when the electrode on one side of the mirror is driven to +5 volts, the mirror is driven toward the opposite side of the 0 volts. When the CMOS voltages are reversed, the mirror will be tilted toward the other side. Therefore, the on/off state of each mirror can be controlled via the CMOS. For a more detailed description of DMDs such as those described above, please refer to "Introduction to Microdisplays" by David Armitage et al. (published by John Wiley and Sons in 2006). In the past decade or so, there has been no change in the design of DMDs. However, such more complex designs and several moving parts in each mirror assembly require a corresponding complex microelectromechanical system (MEMS) process. Complexity-6-201024203 improves manufacturing costs and may affect the extent to which each mirror assembly can be miniaturized. It is preferable to provide a DMD having a simpler design than the conventional DMD. In a first aspect, a digital micromirror device is provided, the digital micromirror device comprising an array of micromirror assemblies positioned on a substrate, each φ micromirror assembly comprising: and the substrate Separating a mirror having an upper reflective surface and a lower support surface; supporting a handle of the mirror, the handle extending from the substrate to the lower support surface, the handle defining a tilt axis of the mirror; One An electrode and a second electrode, the first and second electrodes are positioned on each side of the handle, and are individually addressable to each electrode via an electronic circuit within the substrate, wherein φ is elastically flexible The material constitutes the handle such that the mirror is tilted toward the first electrode or toward the second electrode by an electrostatic force. Because the mirror is tilted against the flexible handle, the present invention does not require a yoke in a conventional DMD and Twisted hinge configuration. This approach greatly simplifies the overall design and manufacture of the DMD. 'Or the handle can be made of a polymer such as polydimethylsiloxane (PDMS). PDMS has a lower Young's Young's modulus (less than 1000 MPa (million bars)), so that the 201024203 handle can be bent by the electrostatic force applied by the one or more electrodes. Furthermore, the applicant has previously demonstrated that PDMS is in the MEMS ( The utility of MEMS) and its ease of integration into microelectromechanical systems (MEMS) processes.
或者，該上反射表面的全部範圍都是平坦的。其與先 前技術的 DMD有懸殊差異，在先前技術的 DMD中， 上反射表面中有因與該柄接合而造成的一中央小凹坑。與 先前技術之裝置相比時，完全平坦的上反射表面有利地改 善了光學品質。 或者，該鏡包含一金屬板，該金屬板界定了該上反射 表面。或者，該金屬板是一鋁板。 或者，該鏡進一步包含該金屬板之一支承平台，該支 承平台界定該下支承表面。因此，該鏡通常是包含該金屬 板的一上金屬板及下支承平台之一整合式兩零件結構。 或者’該支承平台實質上與該金屬板是共延伸的。Alternatively, the entire range of the upper reflective surface is flat. It differs from the prior art DMD in which a central small pit is formed in the upper reflective surface due to engagement with the handle. The fully flat upper reflective surface advantageously improves optical quality when compared to prior art devices. Alternatively, the mirror includes a metal plate that defines the upper reflective surface. Alternatively, the metal plate is an aluminum plate. Alternatively, the mirror further comprises a support platform for the metal sheet, the support platform defining the lower support surface. Therefore, the mirror is usually an integrated two-part structure comprising an upper metal plate and a lower support platform of the metal plate. Or the support platform is substantially coextensive with the metal sheet.
或者，係由相同的材料構成該支承平台及柄。通常是 在一單一的沈積步驟中一起形成該柄及支承平台。例如， 沈積PDMS時，可一起形成該柄及支承平台。 或者’該第一及第二電極界定該鏡之第一及第二接合 塾(landing pad ) 〇 或者’該鏡具有用來接觸個別的第一及第二接合墊之 第一及第二接觸點’且其中係由一聚合物構成該第一及第 二接觸點。因爲係由一聚合物（例如，PDMS)構成該等 接觸點，所以該鏡被黏附在任一電極的可能性被最小化。 或者’該支承平台界定了該第一及第二接觸點。因此 -8 - 201024203 ’不需要用來解決可能的黏附（stiction )問題之額外的特 徵。該支承平台執行支承一鋁上反射表面以及將該鏡與該 等電極間之黏附最小化之雙重功能。 . 或者，該鏡係電性連接到一偏壓電位。該偏壓電位通 . 常將該鏡保持在一高電位，因而可經由被 CMOS電壓（ 通常爲5伏特）控制的電極而使該鏡傾斜。 可由一導電聚合物構成該柄，使該柄提供至該偏壓電 ❹ 位的電連接。例如，可由以金屬離子佈植的 PDMS構成 該柄。 或者，複數個鏡可被成列地耦合在一起，每一列係電 性連接到該偏壓電位之一端。因此，該偏壓電位可經由一 共同接點而被施加到一整列的鏡。 或者，每一列的鏡具有一共同傾斜軸。 或者，一列中之鄰接鏡係經由一連桿組而被耦合在一 起，沿著該共同傾斜軸而對準該連桿組。 φ 或者，該基材是包含一或多個 CMOS層之矽基材， 該等 CMOS層包含該電子電路。 在一第二觀點中，提供了一種投影機，該投影機包含 前文所述之數位微鏡裝置。採用 DMD之投影機及投影 系統將是熟悉此項技術者習知的。 • 在一第三觀點中，提供了 一種製造微鏡總成之方法， 該方法包含下列步驟： (a)在一基材上形成被間隔開的一對電極，該等電 極被連接到該基材中之下方電子電路； -9- 201024203 (b)在該等電極及該基材之上沈積一層犧牲材料； (C)在該犧牲材料中界定一柄開孔，以便形成一臺 架，該柄開孔被定位在該等電極之間； (d) 在該臺架之上沈積一層彈性可撓材料； (e) 在該可撓層之上沈積一金屬層； (f) 鈾刻穿過該金屬層及該可撓層，以便界定被支 承在一可撓材料柄上之一個別的微鏡，該微鏡包含被熔接 到一支承平台之一金屬層；以及 (g) 去除該犧牲材料，以便提供該微鏡總成。 根據該第三觀點之方法使用最少數目的製造步驟而提 供一種製造 DMD的簡單且有效之方式。 或者，係由聚二甲基矽氧烷（PDMS )構成該彈性可 撓材料。 或者，該犧牲材料是光阻。 或者，係由鋁構成該金屬層。 或者，在該基材上同時製造一陣列的微鏡，該陣列界 定一數位微鏡裝置。 或者，該基材是包含一或多個 CMOS層之一矽基材 ，該等 CMOS層包含該電子電路。 在一第三觀點中，提供了 一種微鏡總成，該微鏡總成 包含被一柄支承的一可傾斜鏡，其中係由一彈性可撓材料 構成該柄。 或者，該可傾斜鏡包含一具有一上反射表面之一金屬 層。 -10- 201024203 或者，該可傾斜鏡進一步包含一支承平台，該支承平 台上安裝該金屬層，係由該彈性可撓材料構成該支承平台 〇 或者，係由聚二甲基矽氧烷（PDMS )構成該彈性可 撓材料。 或者，一靜電力可使該鏡傾斜。 或者，一對電極被定位在該柄之每一側上，該等電極 提供了該靜電力之至少一部分。 【實施方式】 本案申請人先前已證明了聚二甲基矽氧烷（PDMS ) 在微機電系統（MEM S )中之多方面適用性（請參閱諸如 於 2008 年 6月 20日提出申請的美國專利申請案 12/142,779、以及於 2007年 3月 12日提出申請的美 國專利申請案 1 1 /685,084，本發明特此引用每一該等專 φ 利申請案之內容以供參照）。將 PDMS 加入傳統的 MEMS製程時，尤其已造成機械噴墨裝置的改良，且開 啓了實驗室晶片（lab-on-a-chip )及微分析系統（ microanalysis system)的新領域。 現在發現了 PDMS具有適用於 DMD的一些特性， • 因而可以有比目前可自市場購得的 DMD簡單許多之設 計。請參閱第 1及 2圖，圖中示出根據本發明的一數 位微鏡裝置之一部分。該 DMD包含被配置在基材 2的 表面上的一矩陣之複數個微鏡總成 1。每一微鏡總成 1 -11 - 201024203 通常與鄰近的微鏡總成之間隔離了小於 5微米（例如， 大約 2微米）。該微鏡總成包含與基材 2間隔開之一 鏡 5。每一鏡通常是正方形的，且具有範圍大約在 10 至 20微米之長度。 鏡 5包含一鋁板 7，該鋁板 7界定了該鏡的一上 反射表面 8。鏡 5進一步包含一支承平台 10，該支承 平台 10界定了該鏡的一下支承表面 11。在該 DMD 的 MEMS製造期間，鋁板 7被熔接到支承平台 10。 參 由於被安裝在支承平台 10上的鋁板 7，所以可將鏡 5 的上反射表面 8製造成在該表面的整個範圍是平坦的。 此種方式有利地提供了優異的光清晰度。相比之下，先前 技術的 DMD通常在反射表面中之支承柱被接合到該鏡 處有凹陷。 雖然鋁是通常被用於 DMD的反射材料，但是應可 了解：亦可替代地使用其他材料（例如，鈦）。 自基材 2延伸到下支承表面 1 1的—彈性可撓柄 ❹ 13支承著鏡5。柄13及支承平台10形成了由相同 的可撓材料構成之一整合式結構。通常係由具有小於 1 000 Mpa的楊氏模數之一聚合物構成柄13及支承平台 1〇。用來形成柄13的一較佳材料是具有大約600 MPa 的楊氏模數之聚二甲基矽氧烷。 柄13界定了鏡5之傾斜軸。如第2圖更清楚地 - 顯市’鏡 5 能夠在闻達大約 ±15 度（通常爲 ±7 至 15度）的角度下依著該傾斜軸而傾斜。彈性可撓柄 Η -12- 201024203 應與將堅固的柄以鉸鏈安裝在 DMD的基部而可讓鏡傾 斜的先前技術之 DMD有很大的不同。 柄 1 3的形式可以是被連接到鏡 5的形心之一支承 _ 柱。或者，柄 13可至少部分地沿著該傾斜軸而延伸。 . 柄13之形式通常爲沿著該傾斜軸延伸且與鏡 5共延伸 之一支承壁。 —第一電極 15 及一第二電極 16被定位在柄 13 φ 之每一側。矽基材 2中能夠以靜電引力使鏡 5傾斜之 電子電路可個別地定址到該第一及第二電極。下文中將更 詳細地說明該 DMD之典型作業。該電子電路被包含在 該基材的上方部分中所含的 CMOS層 18中。 如第 2圖最清晰地顯示，當鏡 5傾斜時，該第一 及第二電極界定了鏡 5之接合墊。先前技術的 DMD之 一問題在於鏡/軛與接合墊間之黏附力。黏附力可能使該 鏡永久性地被黏附在一個接合墊上，因而使鏡變得無法操 φ 作。然而，在微鏡總成1中，支承平台1〇界定了用來 接觸該等接合墊之第一及第二接觸點。因爲係由 PDMS 有利地構成支承平台1 〇，所以任何黏附力被最小化。 與先前技術的 DMD比較時，本發明之 DMD在鏡 5被一偏壓電位保持在較高的電位（例如，20至 50伏 特）之情形下將最有效地操作。因而在下方的 5伏特 CMOS電路將該第一或第二電極打開或關閉時，將必要的 靜電力最大化。 可經由支承柄1 3將該偏壓電位施加到鋁板 7。雖 -13- 201024203 然諸如 PDMS等的聚合物材料通常是在電氣上絕緣的， 但是亦可植入諸如鈦離子等的金屬離子，而使這些材料具 有導電性（請參閱諸如 Dubois等人所著的 “Sensor and Actuator A，1 3 0- 1 3 1 (2006), 1 47- 1 54”，本發明特此引用 該文件之內容以供參照）。因此，在使用一導電柄 13 之情形下，可將鋁板 7保持在一高偏壓電位。 或者，如第 3圖所示，可將該等板耦合在一起，並 將偏壓電位自一列鏡的一末端上的一電壓源施加到該列鏡 ，而將該偏壓電位施加到鋁板 7。係經由沿著該等鏡的傾 斜軸而延伸之連桿組 20而將各鄰接的板互連。係沿著 該傾斜軸將該等連桿組定位，以便將該等連桿組對鏡傾斜 的阻力最小化。 雖然連桿組 2 0在鏡傾斜期間不可避免地將遭受小 扭轉力，但是這些連桿組通常不會因該扭轉力而產生疲勞 。這是由於該等耦合構件的可立即減輕任何晶體差排（ crystal dislocation)之微觀尺度（microscopic scale)。 傳統 DMD 中之扭轉鉸鏈也因相同的理由而不會產生疲 勞。 現在請參閱第 2圖，圖中示出一微鏡總成 1係處 於一傾斜位置。爲了移到所示之傾斜位置，CMOS電路 18將第一電極 15設定爲 +5伏特，並將該第二電極 設定爲 〇伏特。因爲該鋁板的偏壓電位被施加到大約 + 45伏特的電位，所以鏡 5受到來自該第一電極的靜電 排斥力，且朝向該第二電極傾斜。當然，將該等電極的極 -14- 201024203 性顛倒時’將使鏡5沿著相反方向傾斜。爲了將鏡5 保持在其傾斜位置，可將兩個電極都設定爲+5伏特或 0伏特。 應可了解：在傾斜期間，柄13屈曲，以便適應鏡 5之傾斜。因此，與先前技術的設計不同，不需要任何複 雜的扭轉鉸鏈配置，即可使該鏡能夠進行有彈性的傾斜。 現在請參閱第 4至 7圖，圖中示出用來製造第 1 φ 圖所示的 DMD 之一簡化 MEMS 製程。在第 4 至 7 圖中，並未示出 CMOS 層 18。 在第 4 圖所示之第一步驟中，將 1微米的鋁層 CMOS基材 1上，並蝕刻以界定個別的第一及第二電極 15及 16，而形成該等電極（或接合墊）。該等鋁電極 被連接到下方 CMOS中之一上金屬層，因而可個別地控 制每一電極。 在第 5圖所示之第二步驟中，一光阻層 22被旋塗 φ 到該等電極上，並在該光阻層 22中產生圖案，以便界 定柄開孔 23。該光阻層 22被用來作爲一犧牲臺架，以 供後續沈積 PDMS及鋁。 在第 6圖所示之第三步驟中，一 PDMS層被沈積 到光阻層 22上，然後再沈積一鋁層。該 PDMS層包含 每一微鏡總成的柄13及支承平台1〇。該鋁層包含該等 具有上反射表面 8之板 7。 在第 7圖所示之第四步驟中’該 PDMS及鋁層被 蝕刻，以便界定個別的鏡5。該蝕刻步驟使用被適當地產 -15- 201024203 生圖案的一光阻罩幕（圖中未示出），且可能需要不同的 蝕刻化學劑，用以蝕刻穿過不同的層。 在最後步驟中，使犧牲光阻 22暴露於一氧化電漿 (例如，氧氣電漿），而去除該犧牲光阻 22。該最後的 “灰化”（“ashing”）步驟提供了第 1圖所示之 DMD。 第 8圖示出採用前文所述的 DMD之一典型的簡報 型投影機 1 〇〇 (例如，影像投影機或視訊投影機）。採用 習知 DMD的任何簡報型投影機可替代地採用根據本發 明的 DMD。如美國專利 6,966,659 (本發明特此引用該 專利之內容以供參照）所述，該投影機可額外地包含一列 印頭，用以列印自一電腦系統 1 〇 1接收的影像。例如， 如第 8圖所示，可自投影機 100的後部輸出列印的資 料 1 0 2。 當然，應可了解：以僅爲舉例之方式說明了本發明， 且可在伴隨的申請專利範圍中界定的本發明之範圍內，對 細節作出修改。 【圖式簡單說明】 前文已參照各附圖而以只係爲舉例之方式說明了本發 明之一隨意的實施例，在該等附圖中： 第 1圖是根據本發明的一 DMD之一斷面示意圖； 第 2 圖示出處於一傾斜位置的第 1圖所示之 〇MD ; 第 3圖是第 1圖所示 DMD之一平視圖； 201024203 第 4圖示出用來形成電極的 MEMS製程之第一階 段； 第 5圖示出用來形成犧牲臺架的 MEMS製程之第 二階段； 第 6圖示出用來沈積柄的 MEMS製程之第三階段 > 第 7圖示出用來界定個別的微鏡的 MEMS製程之 φ 第四階段；以及 第 8圖示出採用根據本發明的一 DMD之一簡報型 投影機。 【主要元件符號說明】 1 :微鏡總成 2 :基材 5 :鏡 φ 7 :鋁板 8 :上反射表面 10 :支承平台 1 1 :下支承表面 1 3 :彈性可撓柄 15 :第一電極 16 :第二電極 18:互補金屬氧化物半導體層 2 0 :連桿組 -17- 201024203 2 2 :光阻層 2 3 :柄開孔 100 :簡報型投影機 1 0 1 :電腦系統 1 0 2 :列印的資料Alternatively, the support platform and the shank are constructed of the same material. The handle and support platform are typically formed together in a single deposition step. For example, when depositing PDMS, the handle and support platform can be formed together. Or 'the first and second electrodes define a first and a second landing pad of the mirror or 'the mirror has first and second contact points for contacting the respective first and second bonding pads 'And wherein the first and second contact points are formed by a polymer. Since the contacts are made up of a polymer (e.g., PDMS), the possibility of the mirror being adhered to either electrode is minimized. Or the 'supporting platform' defines the first and second contact points. Therefore -8 - 201024203 ‘ no additional features are needed to solve the possible sticking problem. The support platform performs the dual function of supporting a reflective surface on the aluminum and minimizing adhesion between the mirror and the electrodes. Alternatively, the mirror is electrically connected to a bias potential. The bias voltage is constantly maintained at a high potential so that the mirror can be tilted via an electrode controlled by a CMOS voltage (typically 5 volts). The handle can be constructed of a conductive polymer that provides electrical connection to the biasing electrical position. For example, the handle can be constructed from PDMS implanted with metal ions. Alternatively, a plurality of mirrors may be coupled together in a column, each column being electrically coupled to one of the bias potentials. Thus, the bias potential can be applied to an array of mirrors via a common contact. Alternatively, the mirrors of each column have a common tilt axis. Alternatively, adjacent mirrors in a column are coupled together via a set of links that are aligned along the common tilt axis. φ Alternatively, the substrate is a germanium substrate comprising one or more CMOS layers, the CMOS layers comprising the electronic circuitry. In a second aspect, a projector is provided, the projector comprising a digital micromirror device as hereinbefore described. Projectors and projection systems employing DMD will be familiar to those skilled in the art. • In a third aspect, there is provided a method of fabricating a micromirror assembly, the method comprising the steps of: (a) forming a pair of spaced apart electrodes on a substrate, the electrodes being connected to the substrate a lower electronic circuit in the material; -9- 201024203 (b) depositing a sacrificial material on the electrodes and the substrate; (C) defining a handle opening in the sacrificial material to form a frame, a handle opening is positioned between the electrodes; (d) depositing an elastically flexible material over the gantry; (e) depositing a metal layer over the flexible layer; (f) uranium engraving The metal layer and the flexible layer to define an individual micromirror supported on a handle of a flexible material, the micromirror comprising a metal layer fused to a support platform; and (g) removing the sacrificial material In order to provide the micromirror assembly. The method according to this third aspect provides a simple and efficient way of fabricating DMD using a minimum number of manufacturing steps. Alternatively, the elastically flexible material is composed of polydimethyl siloxane (PDMS). Alternatively, the sacrificial material is a photoresist. Alternatively, the metal layer is composed of aluminum. Alternatively, an array of micromirrors is fabricated simultaneously on the substrate, the array defining a digital micromirror device. Alternatively, the substrate is a substrate comprising one or more CMOS layers, the CMOS layers comprising the electronic circuitry. In a third aspect, a micromirror assembly is provided, the micromirror assembly comprising a tiltable mirror supported by a handle, wherein the handle is formed of an elastically flexible material. Alternatively, the tiltable mirror comprises a metal layer having an upper reflective surface. -10-201024203 Alternatively, the tiltable mirror further comprises a support platform on which the metal layer is mounted, the elastic platform is made up of the support platform or by polydimethyl siloxane (PDMS) ) constitutes the elastically flexible material. Alternatively, an electrostatic force can tilt the mirror. Alternatively, a pair of electrodes are positioned on each side of the handle that provides at least a portion of the electrostatic force. [Embodiment] The applicant of the present case has previously demonstrated the applicability of polydimethyl methoxy oxane (PDMS) in the microelectromechanical system (MEM S ) (see, for example, the United States filed on June 20, 2008) U.S. Patent Application Serial No. 1 </ RTI> </ RTI> </ RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> </ RTI> <RTIgt; The addition of PDMS to traditional MEMS processes has in particular led to improvements in mechanical inkjet devices and has opened up new areas of lab-on-a-chip and microanalysis systems. It has now been found that PDMS has some features that are suitable for DMD, and thus can be designed to be much simpler than the DMD currently available from the market. Referring to Figures 1 and 2, there is shown a portion of a digital micromirror device in accordance with the present invention. The DMD comprises a plurality of micromirror assemblies 1 arranged in a matrix on the surface of the substrate 2. Each micromirror assembly 1 -11 - 201024203 is typically separated from adjacent micromirror assemblies by less than 5 microns (eg, approximately 2 microns). The micromirror assembly includes a mirror 5 spaced from the substrate 2. Each mirror is typically square and has a length ranging from about 10 to 20 microns. The mirror 5 includes an aluminum plate 7, which defines an upper reflective surface 8 of the mirror. The mirror 5 further includes a support platform 10 that defines a lower bearing surface 11 of the mirror. During the MEMS fabrication of the DMD, the aluminum sheet 7 is fused to the support platform 10. With reference to the aluminum plate 7 mounted on the support platform 10, the upper reflecting surface 8 of the mirror 5 can be made flat over the entire range of the surface. This approach advantageously provides excellent light clarity. In contrast, prior art DMDs typically have recesses in which the support posts in the reflective surface are bonded to the mirror. Although aluminum is a reflective material commonly used in DMD, it should be understood that other materials (e.g., titanium) may alternatively be used. The elastically flexible handle ❹ 13 extending from the base material 2 to the lower support surface 1 1 supports the mirror 5. The shank 13 and the support platform 10 form an integrated structure of the same flexible material. The handle 13 and the support platform 1 are typically constructed of a polymer having a Young's modulus of less than 1 000 MPa. A preferred material for forming the shank 13 is a polydimethyl siloxane having a Young's modulus of about 600 MPa. The shank 13 defines the tilt axis of the mirror 5. As is clearer in Figure 2, the Vision 5 can be tilted according to the tilt axis at an angle of approximately ±15 degrees (typically ±7 to 15 degrees). Elastic Resilience Shank Η -12- 201024203 It should be very different from the prior art DMD that has a solid handle hinged to the base of the DMD to tilt the mirror. The shank 13 may be in the form of a support _ column connected to one of the centroids of the mirror 5. Alternatively, the handle 13 can extend at least partially along the tilt axis. The shank 13 is typically in the form of a support wall extending along the axis of inclination and coextensive with the mirror 5. - The first electrode 15 and a second electrode 16 are positioned on each side of the shank 13 φ. An electronic circuit in the crucible substrate 2 capable of tilting the mirror 5 by electrostatic attraction can be individually addressed to the first and second electrodes. A typical operation of the DMD will be described in more detail below. The electronic circuit is included in the CMOS layer 18 contained in the upper portion of the substrate. As shown most clearly in Figure 2, the first and second electrodes define the bond pads of the mirror 5 when the mirror 5 is tilted. One of the problems with prior art DMDs is the adhesion between the mirror/yoke and the bond pads. Adhesion may cause the mirror to be permanently adhered to a bond pad, thus rendering the mirror inoperable. However, in the micromirror assembly 1, the support platform 1 defines the first and second contact points for contacting the pads. Since the support platform 1 有利 is advantageously formed by the PDMS, any adhesion is minimized. The DMD of the present invention will operate most efficiently when the mirror 5 is held at a higher potential (e.g., 20 to 50 volts) by a bias potential when compared to prior art DMDs. Thus, the necessary electrostatic force is maximized when the lower 5 volt CMOS circuit turns the first or second electrode on or off. This bias potential can be applied to the aluminum plate 7 via the support handle 13. Although-13-201024203, polymer materials such as PDMS are usually electrically insulated, but metal ions such as titanium ions can also be implanted to make these materials conductive (see, for example, Dubois et al. "Sensor and Actuator A, 1 3 0- 1 3 1 (2006), 1 47- 1 54", the disclosure of which is incorporated herein by reference. Therefore, in the case where a conductive handle 13 is used, the aluminum plate 7 can be maintained at a high bias potential. Alternatively, as shown in FIG. 3, the plates may be coupled together and a bias voltage is applied to the column mirror from a voltage source on one end of the column of mirrors, and the bias potential is applied to Aluminum plate 7. The adjacent plates are interconnected via a set of links 20 that extend along the tilt axis of the mirrors. The sets of links are positioned along the tilt axis to minimize the resistance of the sets of links to tilting the mirror. Although the link set 20 inevitably suffers from small torsional forces during mirror tilt, these link sets typically do not experience fatigue due to the torsional forces. This is due to the fact that the coupling members can immediately alleviate the microscopic scale of any crystal dislocation. Torsion hinges in traditional DMDs do not suffer for the same reason. Referring now to Figure 2, a micromirror assembly 1 is shown in an inclined position. To move to the tilt position shown, CMOS circuit 18 sets first electrode 15 to +5 volts and sets the second electrode to 〇volts. Since the bias potential of the aluminum plate is applied to a potential of about +45 volts, the mirror 5 receives an electrostatic repulsion force from the first electrode and is inclined toward the second electrode. Of course, when the poles of the electrodes are inverted -14- 201024203, the mirror 5 will be tilted in the opposite direction. To maintain the mirror 5 in its tilted position, both electrodes can be set to +5 volts or 0 volts. It should be understood that during tilting, the shank 13 flexes to accommodate the tilt of the mirror 5. Thus, unlike prior art designs, the mirror can be resiliently tilted without the need for any complex torsional hinge configuration. Refer now to Figures 4 through 7, which show a simplified MEMS process used to fabricate the DMD shown in Figure 1 φ. In Figures 4 through 7, the CMOS layer 18 is not shown. In the first step shown in FIG. 4, a 1 micron aluminum layer CMOS substrate 1 is etched to define individual first and second electrodes 15 and 16 to form the electrodes (or bond pads). . The aluminum electrodes are connected to a metal layer on one of the lower CMOS electrodes so that each electrode can be individually controlled. In the second step shown in Fig. 5, a photoresist layer 22 is spin-coated φ onto the electrodes, and a pattern is created in the photoresist layer 22 to define the handle opening 23. The photoresist layer 22 is used as a sacrificial gantry for subsequent deposition of PDMS and aluminum. In the third step shown in Fig. 6, a PDMS layer is deposited on the photoresist layer 22, and then an aluminum layer is deposited. The PDMS layer includes a shank 13 and a support platform 1〇 for each micromirror assembly. The aluminum layer comprises the plates 7 having the upper reflective surface 8. In the fourth step shown in Figure 7, the PDMS and aluminum layers are etched to define individual mirrors 5. This etch step uses a photoresist mask (not shown) that is patterned by a suitable -15-201024203 and may require different etch chemistries to etch through the different layers. In the final step, the sacrificial photoresist 22 is exposed to an oxidizing plasma (e.g., oxygen plasma) to remove the sacrificial photoresist 22. This final "ashing" step provides the DMD shown in Figure 1. Fig. 8 shows a typical presentation type projector 1 (for example, a video projector or a video projector) which is one of the DMDs described above. Any presentation type projector employing the conventional DMD may alternatively employ the DMD according to the present invention. The projector may additionally include a list of printheads for printing images received from a computer system 1 〇 1 as described in U.S. Patent No. 6,966,659, the disclosure of which is incorporated herein by reference. For example, as shown in Fig. 8, the printed material 1 0 2 can be output from the rear of the projector 100. It is to be understood that the invention is described by way of example only, and the details may be modified within the scope of the invention as defined in the accompanying claims. BRIEF DESCRIPTION OF THE DRAWINGS [0009] One of the arbitrarily described embodiments of the present invention has been described by way of example only with reference to the accompanying drawings, in which: FIG. 1 is one of a DMD according to the present invention. A schematic view of the cross section; Fig. 2 shows the 〇MD shown in Fig. 1 at an inclined position; Fig. 3 is a plan view of the DMD shown in Fig. 1; 201024203 Fig. 4 shows a MEMS process for forming an electrode The first stage; Figure 5 shows the second stage of the MEMS process used to form the sacrificial gantry; Figure 6 shows the third stage of the MEMS process used to deposit the shank> Figure 7 shows The fourth stage of the MEMS process of the individual micromirrors; and Fig. 8 shows a briefing type projector using a DMD according to the present invention. [Main component symbol description] 1 : Micromirror assembly 2 : Substrate 5 : Mirror φ 7 : Aluminum plate 8 : Upper reflective surface 10 : Supporting platform 1 1 : Lower bearing surface 1 3 : Elastic flexible handle 15 : First electrode 16: Second electrode 18: Complementary metal oxide semiconductor layer 20: Link group -17-201024203 2 2: Photoresist layer 2 3: Handle opening 100: Brief type projector 1 0 1 : Computer system 1 0 2 : printed information
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