1297418 96年11月9曰補充修正無劃線頁 九、發明說明· 【發明所屬之技術領域】 本發明係關於一種色輪及其蓋片，特別係關於一種用 於投影系統中之色輪及其蓋片。 【先前技術】 投影系統依其原理可區分為液晶投影系統(Liquid Crystal Display，LCD)、單晶石夕液晶投影糸統(Liquid Crystal on Silicon，LCOS)、數位光源處理技術投影系銃(Digital Light Processing，DLP)···等，而 DLP 由於具有高亮度、 正確的色調重現性、快速的反應時間、無雜訊以及輕 薄短小等優點，已成為目前新一代熱門的投影技術之一。 在DLP式投影系統中，係採用數位控制，並利用反射 光原理，將光源集光之後經由透鏡聚焦，再穿過具有彩色 濾光片之色輪後，投射至數位微鏡晶片（Digital Micro-mirror Device，DMD )上。由於微鏡晶片上具有許 多微小的可動鏡片，經由驅動電極控制可動鏡片傾斜角 度以及偏轉時間，再藉由切換光的反射方向由鏡頭組 投射至螢幕呈像。 請參照圖1A所示，其顯示習知之色輪之側視圖。色 輪1主要係包含一馬達11、一彩色濾光片12以及一蓋片 13。其中，彩色濾光片12以一面與蓋片13黏合，另一面 亦利用黏著膠固定在馬達11上，藉由馬達11的帶動俾 使彩色濾光片12旋轉。 1297418 96年11月9日補充修正無劃線頁 請參照圖1B所示，其顯示習知之色輪中彩色濾光片 與蓋片之上視圖。彩色濾光片12與蓋片13間係以膠材黏 結，目前產業界所使用之彩色濾光片12係由數片不同顏 色的玻璃板組合而成，並且彩色濾光片12與蓋片13均為 環形以便設置於馬達之軸心蓋上。 由於在一般投影系統中，色輪之前一個元件為光源， 因此在投影系統運轉時，色輪會接收到相當高的熱量並使 溫度快速升高。一般色輪使用之黏著膠耐熱溫度約為 150°C至180°C，光源發熱所產生的溫度則約為150°C至. 200°C，故黏著膠在此一溫度下易發生脆化現象而造成彩 色濾光片12與馬達11間之黏著力下降。再加上一般色輪 1所使用之馬達11轉速均高於7200轉，使得彩色濾光片 12中之單一玻璃所需承受之旋轉拉力（離心力）相當大。因 此，當色輪1在高速旋轉以及高溫運轉之情況下，更容易 造成彩色濾光片12產生位移甚至脫落的情形，進而造成 產品品質下降。因此，發明人乃亟思一種可降低運轉中之 色輪溫度以避免彩色濾光片脫落之色輪。 【發明内容】 有鑑於上述課題，本發明之目的為提供一種可產生擾 動氣流之色輪及其蓋片。 緣是，為達上述目的，本發明提供了一種蓋片，其係 用於一滤光單元，濾光單元包含一蓋片與一彩色濾光片， 其中，彩色濾光片係設置於蓋片之一第一表面，而蓋片之 1297418 96年11月9日補充修正無劃線頁 特徵為：蓋片的外周圍具有複數個散熱凸部，蓋片具有一 第一半徑以及一第二半徑，且第一半徑不等於第二半徑。 為達上述目的，本發明更提供了一種色輪，其包含一 馬達以及一濾光單元，而濾·光單元係設置於馬達上。濾光 單元具有一彩色濾光片與一蓋片，彩色濾光片係設置於蓋 片之一第一表面，蓋片的外周圍具有複數個散熱凸部，蓋 片具有一第一半徑以及一第二半徑，且第一半徑不等於第 二半徑。 承上所述，因依本發明之色輪及其蓋片中，蓋片的周 圍係具有至少一凸部，故此一凸部於色輪運轉時，可產生 較大氣流以發揮較佳之散熱冷卻效果，使得色輪之整體溫 度得以降低。進而言之，由於本發明之色輪及其蓋片中， 蓋片的周圍具有至少一凸部，故當色輪運轉時可產生擾流 作用，而並非如習知色輪中圓形或環形之蓋片僅能產生平 順氣流，因此可對色輪達到較佳之降溫效果。並且，由於 蓋片周圍係具有至少一凸部，故其外圍表面積係大於圓形 或環形蓋片之外圓表面積，如此可增加與空氣接觸面積， 亦有助於色輪之冷卻。因此，本發明之色輪及其蓋片可增 加色輪之散熱效果，避免因色輪溫度過高而造成之彩色濾 光片脫落問題，進而延長色輪之使用壽命。 【實施方式】 以下將參照相關圖式，說明依本發明較佳實施例之蓋 片，其中相同的元件將以相同的參照符號加以說明。 1297418 96年11月9日補充修正無劃線頁 請參照圖2A所示，其顯示依本發明較佳實施例之蓋 片及彩色濾光片之上視圖。本發明較佳實施例之蓋片20 係用於一濾光單元2,濾光單元2包含一蓋片20與一彩色 濾光片12，其中，蓋片20具有一第一表面21，彩色濾光 片12即係利用黏著膠黏合於蓋片20之第一表面21上， 而蓋片20的外周圍具有至少一凸部24，在本實施例中， 係以具有複數個散熱凸部為例，蓋片具有一第一半徑Ri 以及一第二半徑R2，且第一半徑1不等於第二半徑R2。 在本實施例中，蓋片20除具有第一表面21之外，更 具有一第二表面22以及一第三表面23 (請配合參照圖 2B)，其中第二表面22係與第一表面21相對而設，第三 表面23係與第一表面21正交，並且在蓋片20之第一表 面21、第二表面22以及第三表面23上可分別形成有一第 一溝槽211、一第二溝槽221以及一第三溝槽231。 當彩色濾光片12及蓋片20旋轉時，凸部24可產生 不平順氣流，此時第一溝槽211、第二溝槽221以及第三 溝槽231可提供一通道進行導流，使得色輪整體具有較佳 冷卻效果。同時，由於蓋片20上具有第一溝槽211、第二 溝槽221以及第三溝槽231，使得蓋片20與空氣接觸面積 增加，亦有助於散熱。在本實施例中，蓋片20係為多邊 形之一種，故蓋片20周圍所形成之凸部24係為一線性凸 部。然而凸部24的形狀係取決於蓋片20之形狀，因此當 蓋片20為其他形狀時，凸部24亦可能是一非線性凸部。1297418 November 19, 1996 Supplementary correction without scribe page IX, invention descriptions [Technical field of the invention] The present invention relates to a color wheel and a cover sheet thereof, and more particularly to a color wheel for use in a projection system Its cover sheet. [Prior Art] According to the principle, the projection system can be divided into Liquid Crystal Display (LCD), Liquid Crystal on Silicon (LCOS), and Digital Light Source Processing Technology (Digital Light). Processing, DLP)···, etc., because of its high brightness, correct color reproducibility, fast response time, no noise, and light and thin, DLP has become one of the new generation of popular projection technologies. In the DLP projection system, the digital control is adopted, and the light source is collected by light, concentrated by a lens, and then passed through a color wheel having a color filter, and then projected onto a digital micromirror wafer (Digital Micro- Mirror Device, DMD). Since there are many tiny movable lenses on the micromirror wafer, the tilt angle and the deflection time of the movable lens are controlled via the driving electrodes, and then projected by the lens group to the screen image by the direction of the switching light. Referring to Figure 1A, a side view of a conventional color wheel is shown. The color wheel 1 mainly comprises a motor 11, a color filter 12 and a cover sheet 13. The color filter 12 is bonded to the cover sheet 13 on one side, and the other side is also fixed to the motor 11 by an adhesive, and the color filter 12 is rotated by the driving of the motor 11. 1297418 November 9, 1996 Supplementary Correction Unlined Page Referring to Figure 1B, there is shown a top view of a color filter and a cover sheet in a conventional color wheel. The color filter 12 and the cover sheet 13 are bonded by a glue material. Currently, the color filter 12 used in the industry is composed of a plurality of glass plates of different colors, and the color filter 12 and the cover sheet 13 are combined. They are all ring-shaped so as to be placed on the shaft cover of the motor. Since in the general projection system, one component before the color wheel is the light source, the color wheel receives a relatively high amount of heat and rapidly raises the temperature while the projection system is operating. Generally, the heat-resistant temperature of the adhesive used in the color wheel is about 150 ° C to 180 ° C, and the temperature generated by the heat of the light source is about 150 ° C to 200 ° C, so the adhesive is prone to embrittlement at this temperature. As a result, the adhesion between the color filter 12 and the motor 11 is lowered. In addition, the rotation speed of the motor 11 used in the general color wheel 1 is higher than 7,200 rpm, so that the single glass in the color filter 12 is required to have a relatively large rotational tension (centrifugal force). Therefore, when the color wheel 1 is rotated at a high speed and at a high temperature, the color filter 12 is more likely to be displaced or even detached, resulting in deterioration of product quality. Therefore, the inventor is thinking about a color wheel that can reduce the temperature of the color wheel in operation to prevent the color filter from falling off. SUMMARY OF THE INVENTION In view of the above problems, it is an object of the present invention to provide a color wheel and a cover sheet thereof that can generate a disturbing air flow. In order to achieve the above object, the present invention provides a cover sheet for a filter unit, the filter unit includes a cover sheet and a color filter, wherein the color filter is disposed on the cover sheet. One of the first surfaces, and the cover sheet of 1297418, November 9, 96, supplementary correction, no underlined page feature: the outer periphery of the cover sheet has a plurality of heat dissipation convex portions, and the cover sheet has a first radius and a second radius And the first radius is not equal to the second radius. To achieve the above object, the present invention further provides a color wheel comprising a motor and a filter unit, and the filter unit is disposed on the motor. The filter unit has a color filter and a cover sheet. The color filter is disposed on one of the first surfaces of the cover sheet. The outer periphery of the cover sheet has a plurality of heat dissipation protrusions, and the cover sheet has a first radius and a The second radius, and the first radius is not equal to the second radius. According to the above aspect, in the color wheel and the cover sheet thereof according to the present invention, the cover sheet has at least one convex portion around the cover sheet, so that the convex portion can generate a large airflow during the operation of the color wheel to exert better heat dissipation and cooling. The effect is that the overall temperature of the color wheel is reduced. Further, since the color wheel of the present invention and the cover sheet thereof have at least one convex portion around the cover sheet, a spoiler can be generated when the color wheel is operated, instead of being circular or circular as in the conventional color wheel. The cover sheet can only produce a smooth air flow, so that the color wheel can achieve a better cooling effect. Moreover, since the cover sheet has at least one convex portion around it, the peripheral surface area is larger than the circular surface area of the circular or annular cover sheet, so that the contact area with the air can be increased, and the cooling of the color wheel is also facilitated. Therefore, the color wheel and the cover sheet of the invention can increase the heat dissipation effect of the color wheel, avoid the problem of the color filter falling off due to the excessive temperature of the color wheel, and further prolong the service life of the color wheel. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a cover sheet according to a preferred embodiment of the present invention will be described with reference to the accompanying drawings, wherein the same elements will be described with the same reference numerals. 1297418 November 9, 1996 Supplementary Correction Unlined Page Referring to Figure 2A, there is shown a top view of a cover sheet and a color filter in accordance with a preferred embodiment of the present invention. The cover sheet 20 of the preferred embodiment of the present invention is used for a filter unit 2, and the filter unit 2 includes a cover sheet 20 and a color filter 12, wherein the cover sheet 20 has a first surface 21 and a color filter. The light sheet 12 is adhered to the first surface 21 of the cover sheet 20 by an adhesive, and the outer periphery of the cover sheet 20 has at least one convex portion 24. In this embodiment, a plurality of heat dissipation convex portions are taken as an example. The cover sheet has a first radius Ri and a second radius R2, and the first radius 1 is not equal to the second radius R2. In this embodiment, the cover sheet 20 has a second surface 22 and a third surface 23 in addition to the first surface 21 (please refer to FIG. 2B), wherein the second surface 22 is coupled to the first surface 21 The third surface 23 is opposite to the first surface 21, and a first groove 211 and a first surface are respectively formed on the first surface 21, the second surface 22 and the third surface 23 of the cover sheet 20. Two trenches 221 and a third trench 231. When the color filter 12 and the cover sheet 20 rotate, the convex portion 24 can generate an uneven airflow, and the first trench 211, the second trench 221, and the third trench 231 can provide a channel for guiding, so that The color wheel as a whole has a better cooling effect. At the same time, since the cover sheet 20 has the first groove 211, the second groove 221 and the third groove 231, the contact area of the cover sheet 20 with the air is increased, which also contributes to heat dissipation. In the present embodiment, the cover sheet 20 is of a polygonal shape, so that the convex portion 24 formed around the cover sheet 20 is a linear projection. However, the shape of the convex portion 24 depends on the shape of the cover sheet 20, so that when the cover sheet 20 has other shapes, the convex portion 24 may also be a non-linear convex portion.
請參照圖2B所示，其顯示圖2A中蓋片20沿虛線A-A 1297418 96年11月9日補充修正無劃線頁 之剖面圖。在A-A剖面上，蓋片20之第一表面21，第二 表面22以及第三表面23分別形成有第一溝槽211、第二 溝槽221以及第三溝槽231，如前所述，上列溝槽不僅具 有導流作用，更可增加與空氣接觸之表面積，以達到散熱 冷卻效果。其中第三溝槽231更可在色輪旋轉時提供一動 平衡校正功能，將平衡用之一重物25設置於第三溝槽231 中，可避免色輪轉動不平衡導致之構件磨損或脫落。 請參照圖3，其顯示依本發明另一較佳實施例之蓋片 示意圖。其中，蓋片30係用於一濾光單元3並利用黏著 膠與彩色濾光片12黏合，且蓋片30具有至少一凸部31 以發揮擾流作用。在本實施例中，蓋片30係為一多邊形， 故其凸部31亦為一線性凸部。當然其亦可視蓋片30之形 狀而為一非線性凸部。另外，蓋片30之各表面亦可形成 導流用之溝槽以加速冷卻效率或作為動平衡校正時容設 重物之空間（未示於圖中）。 請參照圖4，其顯示依本發明又一較佳實施例之蓋片 示意圖。其中，蓋片40係用於一濾光單元4並利用黏著 膠與彩色濾光片12黏合，且蓋片40具有至少一凸部41 以發揮擾流作用。在本實施例中，蓋片40係具有複數個 鋸齒，故其凸部41亦為一非線性凸部。當然其亦可視蓋 片40之形狀而為一線性凸部。另外，蓋片40之各表面亦 可形成導流用之溝槽以加速冷卻效率或作為動平衡校正 時容設重物之空間（未示於圖中）。 請參照圖5，其顯示依本發明再一較佳實施例之蓋片 1297418 96年11月9日補充修正無劃線頁 示意圖。其中，蓋片50係用於一濾光單元5並利用黏著 膠與彩色濾光片12黏合，且蓋片50具有至少一凸部51 以發揮擾流作用。在本實施例中，蓋片50周圍係由複數 個弧線組成，故其凸部51亦為一非線性凸部。當然其亦 可視蓋片50之形狀而為一線性凸部。另外，蓋片50之各 表面亦可形成導流用之溝槽以加速冷卻效率或作為動平 衡校正時容設重物之空間（未示於圖中）。 以下係本發明之色輪之較佳實施例，為使便於理解， 下述實施例中之元件符號係沿用與前一實施例中相同元 件之符號來說明。 請參照圖6A所示，其顯示依本發明較佳實施例之色 輪之示意圖。依本發明較佳實施例之色輪6係由一馬達11 以及一濾光單元2組成，且濾光單元2係設置於馬達11 上。濾光單元2具有一彩色濾光片12與一蓋片20，彩色 濾光片12係設置於蓋片20之一第一表面21，蓋片20的 周圍具有至少一凸部24。 在本實施例中，蓋片20除具有第一表面21之外’更 具有一第二表面22以及一第三表面23，其中第二表面22 係與第一表面21相對而設，第三表面23係與第一表面21 正交，並且在第一表面21、第二表面22以及第三表面23 上分別形成有一第一溝槽211、一第二溝槽221以及一第 三溝槽231 〇 當馬達11帶動彩色濾光片12及蓋片20旋轉時，凸 部24可產生不平順氣流，此時第一溝槽211、第二溝槽 1297418 96年11月9日補充修正無劃線頁 221以及第三溝槽231可提供一通道進行導流，使得色輪 整體具有較佳冷卻效果。同時，由於蓋片20上具有第一 、 溝槽211、第二溝槽221以及第三溝槽231，使得蓋片20 . 與空氣接觸面積增加，亦有助於散熱。而在本實施例中， 蓋片20係為多邊形之一種，故蓋片20周圍所形成之凸部 24係為一線性凸部，當然蓋片亦可能在周圍係為鋸齒形或 是弧線的組合。而由於凸部24的形狀係取決於蓋片20之 形狀，因此當蓋片20為其他形狀時，凸部24亦可能是一 0 非線性凸部。 請參照圖6B所示，其顯示圖6A之色輪中濾光單元沿 虛線B-B之剖面圖。在本實施例中，蓋片20具有第一溝 槽211、第二溝槽221以及第三溝槽231，如前所述，上 列溝槽不僅具有導流作用，更可增加與空氣接觸之表面 積，以達到散熱冷卻效果。另外，蓋片20之第三溝槽231 更可在色輪6旋轉時提供一動平衡校正功能，將平衡用之 一重物25設置於第三溝槽231中，可避免色輪轉動不平 _ 衡導致之構件磨損或脫落。 綜上所述，由於本發明之色輪及其蓋片中，蓋片的周 圍係具有至少一凸部，此一凸部於色輪運轉時，可產生較 大氣流以發揮較佳之散熱冷卻效果，使得色輪之整體溫度 w 得以降低。進而言之，由於本發明之色輪及其蓋片中，蓋 片的周圍具有至少一凸部，故當色輪運轉時可產生擾流作 用，而並非如習知色輪中圓形或環形之蓋片僅能產生平順 氣流，因此可對色輪達到較佳之散熱效果。並且，由於蓋 12 1297418 96年11月9日補充修正無劃線頁 片周圍係具有至少一凸部，故其外圍表面積係大於圓形或 環形蓋片之外圓表面積，如此可增加與空氣接觸面積，亦 有助於色輪之冷卻。另外，蓋片之表面上形成之溝槽，除 有導流之作用外，亦同時增加了與空氣接觸之面積。再 者，溝槽尚可以作為色輪動平衡校正時設置重物之處。因 此，本發明之色輪及其蓋片可增加色輪之冷卻效果，避免 色輪之溫度過高而造成之彩色濾光片脫落問題並能提供 動平衡校正之空間，進而延長色輪之使用壽命。 以上所述僅為舉例性，而非為限制性者。任何未脫離 本發明之精神與範疇，而對其進行之等效修改或變更，均 應包含於後附之申請專利範圍中。 【圖式簡單說明】 圖1A為一示意圖，顯示習知色輪之侧視圖； 圖1B為一示意圖，顯示習知色輪中彩色濾光片及蓋 片之上視圖， 圖2A為一示意圖，顯示依本發明較佳實施例之蓋片 及濾光單元之上視圖； 圖2B為一示意圖，顯示圖2A之蓋片沿虛線A-A之 剖面圖； 圖3為一示意圖，顯示依本發明另一較佳實施例之蓋 片及濾光單元之上視圖； 圖4為一示意圖，顯示依本發明又一較佳實施例之蓋 片及濾光單元之上視圖； 1297418 96年11月9日補充修正無劃線頁 圖5為一示意圖，顯示依本發明再一較佳實施例之蓋 片及濾光單元之上視圖； 圖6 A為一示意圖，顯示依本發明較佳實施例之色輪； 以及 圖6B為一示意圖，顯示圖6A之色輪中濾光單元沿虛 線B-B之剖面圖。 元件符號說明： 1 色輪 11 馬達 12 彩色濾光片 13 蓋片 2 濾光單元 20 蓋片 21 第一表面 211第一溝槽 ： 22 第二表面 221第二溝槽 23 第三表面 231第三溝槽 24 凸部 25 重物 3 濾光單元 1297418 96年11月9曰補充修正無劃線頁 31 凸部 4 濾光單元 40 蓋片 41 凸部 5 濾光單元 50 蓋片 51 凸部 6 色輪Referring to Fig. 2B, there is shown a cross-sectional view of the cover sheet 20 of Fig. 2A along the dotted line A-A 1297418, November 9, 1996, supplemented with no scribe lines. In the AA section, the first surface 21, the second surface 22, and the third surface 23 of the cover sheet 20 are respectively formed with a first groove 211, a second groove 221, and a third groove 231, as described above. The column trench not only has a diversion effect, but also increases the surface area in contact with the air to achieve a heat dissipation cooling effect. The third groove 231 can further provide a dynamic balance correction function when the color wheel rotates, and a balance weight 25 is disposed in the third groove 231 to prevent the member from being worn or falling off due to the imbalance of the color wheel rotation. Referring to Figure 3, there is shown a schematic view of a cover sheet in accordance with another preferred embodiment of the present invention. The cover sheet 30 is used for a filter unit 3 and is bonded to the color filter 12 by an adhesive, and the cover sheet 30 has at least one convex portion 31 to exert a spoiler effect. In the present embodiment, the cover sheet 30 is a polygonal shape, so that the convex portion 31 is also a linear convex portion. Of course, it can also be a non-linear convex portion depending on the shape of the cover sheet 30. Further, each surface of the cover sheet 30 may also form a groove for guiding the flow to accelerate the cooling efficiency or as a space for accommodating the weight during the dynamic balance correction (not shown). Referring to Figure 4, there is shown a schematic view of a cover sheet in accordance with yet another preferred embodiment of the present invention. The cover sheet 40 is used for a filter unit 4 and is bonded to the color filter 12 by an adhesive, and the cover sheet 40 has at least one convex portion 41 to exert a spoiler effect. In the present embodiment, the cover sheet 40 has a plurality of serrations, so that the convex portion 41 is also a non-linear convex portion. Of course, it is also a linear convex portion depending on the shape of the cover sheet 40. In addition, the surfaces of the cover sheet 40 may also form a groove for guiding the flow to accelerate the cooling efficiency or as a space for accommodating the weight during the dynamic balance correction (not shown). Please refer to FIG. 5, which shows a cover sheet 1297418 according to another preferred embodiment of the present invention. The cover sheet 50 is used for a filter unit 5 and is bonded to the color filter 12 by an adhesive, and the cover sheet 50 has at least one convex portion 51 to exert a spoiler effect. In the present embodiment, the cover sheet 50 is composed of a plurality of arcs, so that the convex portion 51 is also a non-linear convex portion. Of course, it is also a linear convex portion depending on the shape of the cover sheet 50. In addition, the surfaces of the cover sheet 50 may also form a groove for guiding the flow to accelerate the cooling efficiency or as a space for accommodating the weight when the dynamic balance is corrected (not shown). The following is a preferred embodiment of the color wheel of the present invention. For ease of understanding, the component symbols in the following embodiments are denoted by the same reference numerals as in the previous embodiment. Referring to Figure 6A, there is shown a schematic view of a color wheel in accordance with a preferred embodiment of the present invention. The color wheel 6 according to the preferred embodiment of the present invention is composed of a motor 11 and a filter unit 2, and the filter unit 2 is disposed on the motor 11. The filter unit 2 has a color filter 12 and a cover sheet 20, and the color filter 12 is disposed on one of the first surfaces 21 of the cover sheet 20, and the cover sheet 20 has at least one convex portion 24 around it. In this embodiment, the cover sheet 20 has a second surface 22 and a third surface 23 in addition to the first surface 21, wherein the second surface 22 is opposite to the first surface 21, and the third surface is provided. The 23 series is orthogonal to the first surface 21, and a first trench 211, a second trench 221, and a third trench 231 are formed on the first surface 21, the second surface 22, and the third surface 23, respectively. When the motor 11 drives the color filter 12 and the cover sheet 20 to rotate, the convex portion 24 can generate an uneven airflow. At this time, the first groove 211 and the second groove 1297418 are supplemented and corrected on November 9, 1996. The second groove 231 and the third groove 231 can provide a channel for conducting the flow, so that the color wheel as a whole has a better cooling effect. At the same time, since the cover sheet 20 has the first, the groove 211, the second groove 221 and the third groove 231, the contact area of the cover sheet 20 with air is increased, which also contributes to heat dissipation. In the present embodiment, the cover sheet 20 is a polygonal shape, so that the convex portion 24 formed around the cover sheet 20 is a linear convex portion. Of course, the cover sheet may also be a zigzag or a combination of curved lines. . Since the shape of the convex portion 24 depends on the shape of the cover sheet 20, when the cover sheet 20 has other shapes, the convex portion 24 may also be a non-linear convex portion. Referring to Fig. 6B, there is shown a cross-sectional view of the filter unit in the color wheel of Fig. 6A along the broken line B-B. In this embodiment, the cover sheet 20 has a first trench 211, a second trench 221, and a third trench 231. As described above, the upper trench not only has a diversion effect, but also increases contact with air. Surface area for thermal cooling. In addition, the third groove 231 of the cover sheet 20 can further provide a dynamic balance correcting function when the color wheel 6 rotates, and a balance weight 25 is disposed in the third groove 231 to prevent the color wheel from rotating unevenly. The components are worn or detached. In summary, in the color wheel and the cover sheet of the present invention, the cover sheet has at least one convex portion around the cover sheet, and the convex portion can generate a large airflow when the color wheel is operated to exert a better heat dissipation and cooling effect. So that the overall temperature w of the color wheel is reduced. Further, since the color wheel of the present invention and the cover sheet thereof have at least one convex portion around the cover sheet, a spoiler can be generated when the color wheel operates, and is not circular or circular as in the conventional color wheel. The cover sheet can only produce a smooth airflow, so that the color wheel can achieve better heat dissipation. Moreover, since the cover 12 1297418 is supplemented and corrected on November 9, 1996, the unlined sheet has at least one convex portion, the peripheral surface area is larger than the circular surface area of the circular or annular cover sheet, thereby increasing the contact with the air. The area also contributes to the cooling of the color wheel. In addition, the grooves formed on the surface of the cover sheet, in addition to the effect of the diversion, also increase the area in contact with the air. Furthermore, the groove can be used as a place for setting the weight when the color wheel is balanced. Therefore, the color wheel and the cover sheet of the invention can increase the cooling effect of the color wheel, avoid the problem of the color filter falling off caused by the excessive temperature of the color wheel, and can provide space for dynamic balance correction, thereby extending the use of the color wheel. life. The above is intended to be illustrative only and not limiting. Any equivalent modifications or alterations to the spirit and scope of the present invention are intended to be included in the scope of the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1A is a schematic view showing a side view of a conventional color wheel; FIG. 1B is a schematic view showing a top view of a color filter and a cover sheet in a conventional color wheel, and FIG. 2A is a schematic view. 2 is a schematic view showing a cover sheet of FIG. 2A along a broken line AA; FIG. 3 is a schematic view showing another embodiment according to the present invention; FIG. 4 is a schematic view showing a top view of a cover sheet and a filter unit according to still another preferred embodiment of the present invention; 1297418 supplemented on November 9, 1996 FIG. 5 is a schematic view showing a top view of a cover sheet and a filter unit according to still another preferred embodiment of the present invention; FIG. 6A is a schematic view showing a color wheel according to a preferred embodiment of the present invention; And FIG. 6B is a schematic view showing a cross-sectional view of the filter unit in the color wheel of FIG. 6A along the broken line BB. Description of component symbols: 1 color wheel 11 motor 12 color filter 13 cover sheet 2 filter unit 20 cover sheet 21 first surface 211 first groove: 22 second surface 221 second groove 23 third surface 231 third Groove 24 convex portion 25 weight 3 filter unit 1297418 November 19, 9 曰 supplementary correction without scribe page 31 convex portion 4 filter unit 40 cover sheet 41 convex portion 5 filter unit 50 cover sheet 51 convex portion 6 color wheel
1515