201108477 六、發明說明： 【發明所屬之技術領域】 本發明係有關於一種光感測器，特別係有關 於一種使用表面聲波元件之光感測器。 【先前技術】 在各種感測器的應用中，感測器内感測元件 (例如：表面聲波元件）之靈敏性（Sensitivity)與 選擇性（Selectivity)的大小，是區分感測器好壞的 重要因素，一般而言，表面聲波元件之電極皆為 不透光之金屬電極，因此當表面聲波元件應用於 光感測器時，就會因為金屬電極之遮蔽，造成入 射光之照射量減少’使得光感測器之靈敏性降低。 【發明内容】 本發明之主要目的係在於提供一種使用表面 聲波元件之光感測器，其包含一壓電基板、一氧 化鋅壓電層以及一透明指又換能器金屬電極層， 該壓電基板係具有一表面，該氧化鋅壓電層係設 置於該壓電基板之該表面，該透明指又換能器金 屬電極層係設置於該氧化鋅壓電層上。由於本發 明之該使用表面聲波元件之光感測器係具有該透 明指叉換能器金屬電極層，因此可提高入射光照 射量’使得光照射於該氧化鋅壓電層之照射量增 加’進而使得整體光感測度增加。 【實施方式】 請參閱第1圖，其係本發明之一較佳實施『 201108477 例，一種使用表面聲波元件之光感測器1〇〇係包 含一壓電基板110、一氧化鋅壓電層丨20以及一 透明指又換能器金屬電極層13〇，該壓電基板11〇 係具有一表面111，該壓電基板11〇之材質係可選 自於石英（Quartz)、鈮酸鋰（LiNb〇3)或鈕酸鋰 (LiTa03 )等，該氧化鋅壓電層12〇係設置於該 壓電基板110之該表面1U，在本實施例中，該氧 化鋅壓電層120係以正軸式（〇n_axis )反應性射 頻磁控濺鍍法形成，該透明指又換能器金屬電極 層130係設置於該氧化鋅壓電層12〇上，該透明 才曰又換此器金屬電極層13〇之材質係可選自於 銀、鈦、銀鈦合金及金銀合金所構成之群組中的 其中一種，在本實施例中，該透明指叉換能器金 屬電極層130之厚度係不大於2〇奈米（nm)，且 該透明指叉換能器金屬電極層丨3〇係具有至少一 輸入電極131及至少一輸出電極132。 由於本發明之該使用表面聲波元件之光感測 器100係具有該透明指叉換能器金屬電極層 130’因此可提高入射光照射量，使得光照射於該 氧化鋅壓電層120之照射量增加，進而使得整體 光感測度增加。 本發明之保護範圍當視後附之申請專利範圍 所界定者為準，任何熟知此項技藝者，在不脫離 本發明之精神和範圍内所作之任何變化與修改， 201108477 均屬於本發明之保護範圍。 - 【圖式簡單說明】 第1圖：依據本發明之一較佳實施例，一種使 表面聲波元件之光感測器示意圖。 【主要元件符號說明】 100使用表面聲波元件之光感測器 110壓電基板 111表面 120氧化鋅壓電層 • 130透明指叉換能器金屬電極層 131輸入電極 132輸出電極201108477 VI. Description of the Invention: [Technical Field] The present invention relates to a photosensor, and more particularly to a photosensor using a surface acoustic wave element. [Prior Art] In various sensor applications, the sensitivity (Sensitivity) and selectivity of the sensing elements (for example, surface acoustic wave elements) in the sensor are different in distinguishing the sensor. Important factors, in general, the electrodes of the surface acoustic wave components are opaque metal electrodes, so when the surface acoustic wave components are applied to the photosensor, the exposure of the metal electrodes is reduced, resulting in a decrease in the amount of incident light. The sensitivity of the photo sensor is reduced. SUMMARY OF THE INVENTION The main object of the present invention is to provide a photo sensor using a surface acoustic wave device, comprising a piezoelectric substrate, a zinc oxide piezoelectric layer and a transparent finger and transducer metal electrode layer, the pressure The electric substrate has a surface, and the zinc oxide piezoelectric layer is disposed on the surface of the piezoelectric substrate, and the transparent finger metal electrode layer is disposed on the zinc oxide piezoelectric layer. Since the photosensor using the surface acoustic wave device of the present invention has the transparent interdigit transducer metal electrode layer, the incident light irradiation amount can be increased to increase the irradiation amount of light irradiated to the zinc oxide piezoelectric layer. This in turn increases the overall light sensitivity. [Embodiment] Please refer to FIG. 1 , which is a preferred embodiment of the present invention. [201108477] A photosensor 1 using a surface acoustic wave element includes a piezoelectric substrate 110 and a zinc oxide piezoelectric layer. The 丨20 and a transparent finger and a transducer metal electrode layer 13A have a surface 111, and the material of the piezoelectric substrate 11 can be selected from quartz (Quartz) and lithium niobate ( LiNb〇3) or lithium nitrite (LiTa03) or the like, the zinc oxide piezoelectric layer 12 is provided on the surface 1U of the piezoelectric substrate 110. In the embodiment, the zinc oxide piezoelectric layer 120 is positive. A shaft type (〇n_axis) reactive RF magnetron sputtering method is formed, and the transparent metal electrode layer 130 is disposed on the piezoelectric layer 12 of the zinc oxide layer, and the transparent metal element is replaced by the metal electrode. The material of the layer 13〇 may be selected from the group consisting of silver, titanium, silver titanium alloy and gold-silver alloy. In the embodiment, the thickness of the transparent finger transducer metal electrode layer 130 is Not more than 2 nanometers (nm), and the transparent interdigitated transducer metal electrode layer 丨3〇 There are at least one input electrode 131 and at least one output electrode 132. Since the photo sensor 100 using the surface acoustic wave device of the present invention has the transparent interdigit transducer metal electrode layer 130', the incident light irradiation amount can be increased, so that the light is irradiated onto the zinc oxide piezoelectric layer 120. The amount increases, which in turn increases the overall light sensitivity. The scope of the present invention is defined by the scope of the appended claims, and any changes and modifications made by those skilled in the art without departing from the spirit and scope of the invention, 201108477 are all protected by the present invention. range. - BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic view showing a photosensor for a surface acoustic wave element in accordance with a preferred embodiment of the present invention. [Description of main component symbols] 100 Photosensor using surface acoustic wave element 110 Piezoelectric substrate 111 Surface 120 Zinc oxide piezoelectric layer • 130 transparent interdigital transducer metal electrode layer 131 Input electrode 132 Output electrode