1251680 柱狀透鏡12則係於入光面具有複數個柱狀凸部⑵， 以及於出光面形成有複數個黑帶條紋(Bg此咖)122。 如圖2所示，經由菲埋耳透鏡11而產生之平行光線20垂 直入射柱狀凸部121後，光線2〇將在柱狀透鏡12中被聚 焦之後由出光面射出，另外，該等黑帶條紋122則係分別 精確地覆蓋在相對於柱狀凸部121之出光面的非聚焦部 123，且黑帶條紋122係以光吸收材料構成，用以吸收非 垂直入射進入柱狀透鏡12的雜散光線以及來自觀看者一 方的環境光，進而可降低外部光線之影響，提高晝面之對 比度。 然而，由於該等黑帶條紋122係規則排列於出光面上 且為相等寬度，因此黑帶條紋丨22規則之間距，使於投影 顯示系統時容易造成光線20的干涉現象，而在視覺上產 生俗稱的干涉紋(Moir6)現象，除了讓觀看者產生不舒服之 視覺外，此外也降低了整個晝面的品質。 由上所述得知，對於晝面品質之改進，投影顯示系統 仍有改善的空間，因此如何提供一種消除在螢幕上造成視 覺不舒服之干涉紋(Moir6)現象之背投螢幕及其光學裝置 實為當前重要的課題之一。 【發明内容】 有鑑於上述課題，本發明之目的為提供一種消除干涉 1251680 紋(MoiM)現象之背投螢幕及其光學裝置。 緣是，為達上述目的，依據本發明之光學裝置包含一 光學元件以及一光線吸收圖案層，其中，光學元件係具有 一入光面與一出光面，入光面係具有一柱狀&部結構，且 柱狀凸部結構係包含一第一凸部與一第二凸部，第一凸部 與第二凸部之頂點至出光面之距離係彼此相異；光線吸收 圖案層係具有複數個光線吸收單元，且光線吸收圖案層係 設置於出光面之上。 又，為達上述目的，依據本發明之背投螢幕包含一第 一光學元件、一光線吸收圖案層以及一第二光學元件，其 中r第一光學元件係具有一入光面與一出光面，入光面係 具有一柱狀凸部結構5且柱狀凸部結構係包含一第一凸部 與一第二凸部，第一凸部與第二凸部之頂點至出光面之距 離係彼此相異；光線吸收圖案層係具有複數個光線吸收單 元，且光線吸收圖案層係設置於出光面之上；第二光學元 件係鄰設於第一光學元件。 承上所述，因依本發明之背投螢幕及其光學裝置係利 用光學元件（第一光學元件）之柱狀凸部結構中該等凸部的 頂點至出光面的距離相異，即光學元件（第一光學元件）的 剖面高度相異，而使光線由入光面進入的基準面不同，而 導致光線在光學元件（第一光學元件）中的聚焦位置不同， 進而使得出光範圍相異而得以消除因為規律的出光範圍 間距所導致的干涉紋現象。 1251680 【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背 投螢幕及其光學裝置，其中相同的元件將以相同的參照符 號加以說明。 請參照圖3所示，依據本發明較佳實施例之光學裝置 2係包含一光學元件21以及一光線吸收圖案層22。 光學元件21係具有一光入射面21A與一出光面 21B，光入射面21A具有一柱狀凸部結構，其係用以將入 射之平行光線聚焦後以進行成像作用，如圖3所示，柱狀 凸部結構係包含一第一凸部211與一第二凸部212，第一 凸部211與第二凸部212之頂點至出光面21B之距離係彼 此相異，即光學元件21之光入射面21A具有高低相異之 柱狀凸部結構。其中，光學元件21係可為一柱狀透鏡， 且第一凸部211與第二凸部212之曲率參數係為相同。 光線吸收圖案層22係設置於光學元件21之出光面 21B上，且具有複數個光線吸收單元221，其係用以吸收 環境的干擾光線及散射光線，在製程中，光線吸收圖案層 22的形成係利用光阻為材料，再以曝光顯影等過程來將光 線吸收單元221精確地分佈在出光面21B的非聚焦部上， 詳細的來說，首先係於光學元件21的出光面21B上塗佈 正顯影或是負顯影光阻，接著再於光學元件21的光入射 面21A之上照射光線進行光阻之曝光，最後經過顯影過程 讓曝光區域能夠去除（正顯影）或是保留（負顯影）而形成如 圖3所示之複數個光線吸收單元221。 1251680 由於光學元件21具有高低相異的柱狀凸部結構，因 此入射光線之光入射面21A係彼此不位於同一水平面上， 由此光線入射後因光入射面21A的彼此相異造成聚焦點 P、P，亦彼此相異，最終俾使光線的出光範圍彼此相異，故 形成寬度不相等之光線吸收單元221，且將具此結構之光 學裝置2應用於成像過程中時，將可消除習知出光範圍的 規律間距所造成的干涉紋效應。 又，如圖4所示，依據本發明較佳實施例之光學裝置 2的柱狀凸部結構更包含一第三凸部213，其之頂點至出 光面21B之距離係與第一凸部211或第二凸部212之頂點 至该出光面21B之距離相異，如上所述，用以造成光線出 光範圍的變化，當然，在本實施例中，光學裝置2更可包 含頂點至出光面之距離與第一凸部211或第二凸部2丨2之 頂點至該出光面21B之距離相異的第四凸部、第五凸部 等等之應用。其中，該等凸部211、212、213之曲率參數 係彼此相同，且該等凸部211、212、213之頂點至出光面 21B之距離係可具有規律性，例如2倍、3倍、6倍等之規 律變化，亦可以是不具規律變化之組合。 承上所述，請參照圖5A〜5E所示，依據本發明較佳實 %例之光學裝置2更包含一光擴散層23，其係設置於出光 面21B之上，如圖5a所示，光擴散層23可以形成於光線 吸收圖案層22上且覆蓋之，抑或可以形成於光學元件21 與光線吸收圖案層22之間（如圖5B所示），另外，光學襞 置2亦可更包含一抗反射層24，其亦可設置於出光面2ib 1251680 之上，如圖5C所示，抗反射層24之設置位置，可以形成 於光線吸收圖案層22上且覆蓋之，抑或可以如圖5D所示 形成於光學元件21與光線吸收圖案層22之間，此外，更 可以將光擴散層23及抗反射層24互相組合形成於光線吸 收圖案層22之上並覆蓋之（如圖5E所示）或是光學元件21 與光線吸收圖案層22之間，以此些結構使此光學裝置2 應用於背投螢幕時，能夠達到增加視角與光線強度的目 的，進而提高背投螢幕之品質。 又，如圖6所示，在本實施例中，光學裝置2之光學 元件21内可填入光擴散微粒，使光學裝置2除了可以增 加視角外，更可以使影像亮度更具均勻性。 再請參考圖7所示，依據本發明較佳實施例之背投螢 幕3，包含一第一光學元件31、一光線吸收圖案層32與 一第二光學元件30。 第一光學元件31係為上述之光學元件21，其結構、 組成與特徵係如前述，故不再贅述，而在本實施例中，第 二光學元件30係鄰設於第一光學元件31，用以與上述之 第一光學元件31組合形成背投螢幕3，其中，第二光學元 件30係為菲淫耳透鏡（Fresnel Lens )，其係用以將光源來 之光線聚集後偏折光線，使離開菲涅耳透鏡之光線成為互 相平行之光線以入射進入柱狀透鏡進行成像。 綜上所述，依據本發明較佳實施例之背投螢幕及其光 學裝置係利用一具有高低相異之柱狀凸部結構的光學元 件（第一光學元件）與光線吸收圖.案層組合成光學裝置，因 1251680 高低相異之柱狀凸部結構造成入射光線之入光面相異，進 而導致聚焦點彼此不相同，以及出光範圍的相異，將此裝 置應用於背投螢幕上，相較於習知，因本發明消除了出光 範圍規律的變化而可進而減低造成視覺不舒服的干涉紋 效應。 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1為一顯示習知背投螢幕之立體示意圖； 圖2為一顯示習知背投螢幕之剖面示意圖； 圖3為一顯示依據本發明較佳實施例之光學裝置之剖 面示意圖； 圖4為一顯示依據本發明較佳實施例之另一光學裝置 之剖面示意圖； 圖5A~5E為一顯示依據本發明較佳實施例之又一光 學裝置的一組示意圖； 圖6為一顯示依據本發明較佳實施例之再一光學裝置 之剖面示意圖；以及 圖7為一顯示依本發明較佳實施例之背投螢幕的示意 圖。 元件符號說明： 11 背投螢幕 菲涅耳透鏡 柱狀透鏡 柱狀凸部 黑帶條紋 非聚焦部 光學裝置 光線 光學元件 光入射面 出光面 第一凸部 第二凸部 第三凸部 光線吸收圖案層 光線吸收單元 聚焦點 聚焦點 光擴散層 抗反射層 背投螢幕 第二光學元件 第一光學元件 光線吸收圖案層 121251680 The lenticular lens 12 has a plurality of columnar convex portions (2) on the light incident surface, and a plurality of black strip stripes (Bg) on the light emitting surface. As shown in FIG. 2, after the parallel ray 20 generated by the Philippine buried lens 11 is perpendicularly incident on the columnar convex portion 121, the ray 2 〇 will be emitted from the illuminating surface after being focused in the lenticular lens 12, and the black ray is emitted. The stripe strips 122 are respectively accurately covered by the non-focusing portion 123 with respect to the light-emitting surface of the columnar convex portion 121, and the black stripe strips 122 are formed of a light absorbing material for absorbing non-normal incidence into the lenticular lens 12. Stray light and ambient light from the viewer can reduce the effects of external light and increase the contrast of the surface. However, since the black stripe stripes 122 are regularly arranged on the light emitting surface and have equal widths, the black stripe strips 22 are regularly spaced apart, so that the interference of the light 20 is easily caused when the display system is projected, and visually generated. The commonly known phenomenon of interference pattern (Moir6), in addition to the viewer's uncomfortable vision, also reduces the quality of the entire face. It is known from the above that there is still room for improvement in the projection display system for the improvement of the quality of the kneading surface, so how to provide a rear projection screen and an optical device thereof which eliminate the interference phenomenon (Moir6) phenomenon which causes visual discomfort on the screen. It is one of the most important topics at present. SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide a rear projection screen and an optical device thereof that eliminate interference with the 1251680 pattern (MoiM) phenomenon. In order to achieve the above object, an optical device according to the present invention comprises an optical element and a light absorbing pattern layer, wherein the optical element has a light incident surface and a light exit surface, and the light incident surface has a columnar shape & a portion structure, and the columnar protrusion structure comprises a first protrusion and a second protrusion, and the distance between the apex of the first protrusion and the second protrusion to the light exit surface is different from each other; the light absorbing pattern layer has A plurality of light absorbing units are disposed, and the light absorbing pattern layer is disposed on the light emitting surface. Moreover, in order to achieve the above object, the rear projection screen according to the present invention comprises a first optical component, a light absorbing pattern layer and a second optical component, wherein the r first optical component has a light incident surface and a light exit surface. The light incident surface has a columnar convex portion structure 5 and the columnar convex portion structure includes a first convex portion and a second convex portion, and the distance between the apex of the first convex portion and the second convex portion to the light emitting surface is mutually The light absorbing pattern layer has a plurality of light absorbing units, and the light absorbing pattern layer is disposed on the light emitting surface; the second optical element is disposed adjacent to the first optical element. As described above, the rear projection screen and the optical device thereof according to the present invention utilize the optical element (first optical element) in the columnar convex portion structure, and the distance from the apex of the convex portion to the light exit surface is different, that is, optical The height of the cross-section of the element (the first optical element) is different, and the reference plane of the light entering from the light-incident surface is different, resulting in different focusing positions of the light in the optical element (the first optical element), thereby making the light-emitting range different. It is possible to eliminate the interference pattern caused by the regular light-emitting range spacing. 1251680 [Embodiment] Hereinafter, a rear projection screen and an optical apparatus thereof 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. Referring to FIG. 3, an optical device 2 according to a preferred embodiment of the present invention includes an optical component 21 and a light absorbing pattern layer 22. The optical element 21 has a light incident surface 21A and a light exit surface 21B. The light incident surface 21A has a columnar convex structure for focusing the incident parallel light to perform imaging, as shown in FIG. The columnar protrusion structure includes a first protrusion 211 and a second protrusion 212. The distance between the apex of the first protrusion 211 and the second protrusion 212 to the light exit surface 21B is different from each other, that is, the optical element 21 The light incident surface 21A has a columnar convex structure having a high and low contrast. The optical element 21 can be a cylindrical lens, and the curvature parameters of the first convex portion 211 and the second convex portion 212 are the same. The light absorbing pattern layer 22 is disposed on the light emitting surface 21B of the optical element 21, and has a plurality of light absorbing units 221 for absorbing ambient interference light and scattered light. In the process, the light absorbing pattern layer 22 is formed. The light absorbing unit 221 is precisely distributed on the non-focusing portion of the light-emitting surface 21B by using a photoresist as a material, and then exposed and developed. Specifically, it is first coated on the light-emitting surface 21B of the optical element 21. The positive development or the negative development photoresist is then irradiated with light on the light incident surface 21A of the optical element 21 for exposure of the photoresist, and finally the development process is performed to allow the exposed area to be removed (positive development) or retained (negative development). A plurality of light absorbing units 221 as shown in FIG. 3 are formed. 1251680 Since the optical element 21 has a columnar convex structure having a high and low phase, the light incident surfaces 21A of the incident light are not located on the same horizontal plane, and thus the focus point P is caused by the light incident surfaces 21A being different from each other after the light is incident. And P, which are also different from each other, and finally make the light-emitting range different from each other, so that the light absorbing unit 221 having an unequal width is formed, and when the optical device 2 having the structure is applied to the imaging process, the elimination can be eliminated. Know the interference ripple effect caused by the regular spacing of the light range. Moreover, as shown in FIG. 4, the columnar protrusion structure of the optical device 2 according to the preferred embodiment of the present invention further includes a third protrusion 213 whose distance from the apex to the light exit surface 21B is different from the first protrusion 211. Or the distance from the apex of the second convex portion 212 to the light-emitting surface 21B is different, as described above, to cause a change in the light-emitting range. Of course, in the embodiment, the optical device 2 may further include a vertex to a light-emitting surface. The application of the fourth convex portion, the fifth convex portion, and the like which are different from the distance from the apex of the first convex portion 211 or the second convex portion 2丨2 to the light-emitting surface 21B. The curvature parameters of the convex portions 211, 212, and 213 are the same as each other, and the distance from the apex of the convex portions 211, 212, and 213 to the light-emitting surface 21B may have a regularity, for example, 2 times, 3 times, and 6 The change in the law of the order can also be a combination of irregular changes. As shown in FIG. 5A to FIG. 5A, the optical device 2 according to the preferred embodiment of the present invention further includes a light diffusing layer 23 disposed on the light emitting surface 21B, as shown in FIG. 5a. The light diffusion layer 23 may be formed on the light absorbing pattern layer 22 and covered, or may be formed between the optical element 21 and the light absorbing pattern layer 22 (as shown in FIG. 5B). In addition, the optical device 2 may further include An anti-reflection layer 24, which may also be disposed on the light-emitting surface 2ib 1251680, as shown in FIG. 5C, the position of the anti-reflection layer 24 may be formed on the light-absorbing pattern layer 22 and covered, or may be as shown in FIG. 5D. The light diffusing layer 23 and the anti-reflective layer 24 are formed on the light absorbing pattern layer 22 and covered with each other (as shown in FIG. 5E). Or between the optical element 21 and the light absorbing pattern layer 22, when the optical device 2 is applied to the rear projection screen with such a structure, the purpose of increasing the viewing angle and the light intensity can be achieved, thereby improving the quality of the rear projection screen. Further, as shown in Fig. 6, in the present embodiment, the optical element 21 of the optical device 2 can be filled with light-diffusing particles, so that the optical device 2 can increase the brightness of the image in addition to the viewing angle. Referring to FIG. 7, a rear projection screen 3 according to a preferred embodiment of the present invention includes a first optical component 31, a light absorbing pattern layer 32 and a second optical component 30. The first optical element 31 is the above-mentioned optical element 21, and its structure, composition and characteristics are as described above, and therefore will not be described again. In the present embodiment, the second optical element 30 is disposed adjacent to the first optical element 31. The second optical component 30 is used to combine the light from the light source to deflect the light. The light leaving the Fresnel lens is made to be parallel to each other to be incident into the lenticular lens for imaging. In summary, the rear projection screen and the optical device thereof according to the preferred embodiment of the present invention utilize an optical element (first optical element) having a columnar convex structure of different heights and a light absorption pattern. In the optical device, the entrance surface of the incident light is different due to the high and low columnar convex structure of 1251680, which causes the focus points to be different from each other, and the light-emitting range is different. The device is applied to the rear projection screen. Compared with the prior art, the invention eliminates the change of the law of the light-emitting range and can further reduce the interference pattern effect which causes visual discomfort. 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. 1 is a schematic perspective view showing a conventional rear projection screen; FIG. 2 is a schematic cross-sectional view showing a conventional rear projection screen; and FIG. 3 is a view showing an optical device according to a preferred embodiment of the present invention. Figure 4 is a cross-sectional view showing another optical device in accordance with a preferred embodiment of the present invention; Figures 5A-5E are a set of schematic views showing another optical device in accordance with a preferred embodiment of the present invention; BRIEF DESCRIPTION OF THE DRAWINGS A cross-sectional view of a further optical device in accordance with a preferred embodiment of the present invention; and FIG. 7 is a schematic view showing a rear projection screen in accordance with a preferred embodiment of the present invention. Description of component symbols: 11 Rear projection screen Fresnel lens Column lens Columnar convex black stripe stripe Non-focusing part Optics Light optics Light incident surface Illumination surface First convex part Second convex part Third convex part Light absorption pattern Layer light absorbing unit focus point focus point light diffusion layer anti-reflection layer rear projection screen second optical element first optical element light absorbing pattern layer 12