五、新型說明： 【新型所屬之技術領域】 本創作係關於一種光學讀寫頭的結構改良，特別是指具 有10%至30%的低反射率分光鏡以及3°至15°的Θ角之光軸 傾斜做設置之光訊號檢出器的一種光學讀寫頭結構》 【先前技術】 音樂光碟片（Compact Disk，CD)、影像光碟片（Video Compact Disk，VCD)及數位式影像光碟片（Digital VideoV. New description: [New technical field] This is a structural improvement of an optical head, especially a low reflectivity beam splitter with 10% to 30% and a corner angle of 3° to 15°. An optical head structure for an optical signal detector with an optical axis tilting. [Prior Art] A compact disc (CD), a video compact disc (VCD), and a digital video disc ( Digital Video
Disk ’ DVD)，高密度數位式影像光碟片hd_dvd，BD—DVD已被 廣泛使用於企業、家庭及個人的生活四周，所以相關業界無 不致力於研發更有效率的讀取或記錄之技術，以提昇CDs、 VCDs及_s、HIH)VD、BD-DVD如此類記錄媒體的品質。 則述之s己錄媒體皆藉由光學讀寫頭經由記錄媒體讀取或 寫入資料。利用雷射二極體組發射之光源透過光學元件組聚 焦於記錄媒體之表面進行讀取或寫入資料的動作，再由光訊 號檢出器接收或檢測其反射強弱訊號。 請參考第-圖，第一圖為習知光學讀寫頭結構之示意 圖。此光學讀寫頭結構包括一記錄媒體101、一光訊號檢出 器102雷射二極體組103、一分光鏡104、一準直透鏡1〇5、 以及一物鏡106。由雷射二極體組103所發射的DVD or CD 雷射光源先穿透光拇104a，再經由分光鏡104作反射，再穿 透過準直透鏡105與物鏡1〇6，並聚焦於記錄媒體101的表 面進行讀取或記錄資料的動作。此雷射光源由記錄媒體1〇1 表面的反射，穿透過物鏡106、準直透鏡105，再經過分光鏡 104分成兩部分，一部份穿透，由分光鏡1〇4至光訊號檢出 器102上，來進行其強弱訊號的偵測動作。另一部份經由分 光鏡104反射，穿透光柵l〇4a，進入雷射二極體組103，造 成雷射二極體組103產生相對強度雜訊問題》此光學讀寫頭 的分光鏡104為達到較高光學效率目的，其反射率通常是介 於35%至85%之間’以取得反射一次、反射兩次及反射一次穿 透一次較佳之光學效率。不過，容易造成記錄媒體1〇1反射 光反饋回雷射雜散光大量增加，請參考第三圖之線型42，所 以導致對雷射產生相對強度雜訊問題。此部份為雷射二極體 組103相對強度雜訊主要來源1。 承上述，同樣的經由光訊號檢出器102表面反射之反射 光105c、105d亦可能經過分光鏡1〇4 '準直透鏡1〇5、物鏡 106後，再一次聚焦於記錄媒體1〇1的表面，然後透過物鏡 106、準直透鏡1〇5、分光鏡1〇4導引至雷射二極體組1〇3， 對雷射產生相對強度雜訊問題。此部份為雷射二極體組1〇3 相對強度雜訊主要來源2。 M379145 » , 1 【新型内容】 本創作之主要目的為降低或解決雷射二極體因記錄媒體 之回饋光而產生之相對強度雜訊的問題。 為達前述之目的’本創作提出一種備有平均反射率介於 10%至30%的低反射率分光鏡之光學讀寫頭，其包含一雷射二 極體組、一光學元件組、一記錄媒體、一光訊號檢出器。此 雷射二極體組發射之雷射光源經光學元件组作反射、穿透 後’並聚焦於記錄媒體表面來進行讀取或寫入資料，再自記 錄媒體表面反射’雷射光由此光學元件組導引至此光訊號檢 出器來偵測強弱訊號。由於光訊號檢出器與一光轴以傾斜3。 至15°的0角度做裝設’因此光訊號檢出器可以將進入之雷 射光直接反射成反射光’使此反射光不回饋至此雷射二極體 之雷射光源。 光學元件組包含一光柵、一低反射率分光鏡、以及一物 鏡，光栅將1光束分為3光束，低反射率分光鏡具有反射及 穿透射雷射光的功能，物鏡用以聚焦雷射光。光學元件組更 包含一耦合鏡，其為增加光耦合效率與調整雷射光的準直度 改變光學倍率。本創作利用低反射分光鏡介於10%至30%的反 射率以及將雷射光做兩次的反射用以降低前述雷射二極體組 103相對強度雜訊主要來源1 ’加上光訊號檢出器與光轴傾斜 5 3至15的0角的設置，用以降低前述雷射二極體相對強度 雜訊主要來源2 ’使本創作之光學讀寫頭達到降低或消除雷射 二極體因記錄媒體回饋光而產生的相對強度雜訊之目的。 本創作的光學讀寫頭使用的低反射率分光鏡具有低廉成 本，將光訊號檢出器與光軸傾斜3。至15。的0角做設置，則 具有優勢的技術。前述兩者的組合能夠有效地降低、或消除 回饋光，以及解決對雷射二極體之相對強度雜訊產生的長久 問題，所以本創作必可以提昇產業界於光學讀寫頭產品的競 爭力，以及強化產品的優勢。 茲配合下列圖示、實施例之詳細說明及申請專利範圍， 將上述及本創作之其他目的與優點詳述於後。 【實施方式】 請參考第二圖，第二圖為本創作光學讀寫頭結構之示意 圖。光學讀寫頭結構包含一記錄媒體2〇1、一光訊號檢出器 202、一雷射二極體組203、以及一光學元件組204。雷射二 極體組203可為單波長或兩波長或三波長之雷射光源。光學 元件組204包含一光柵204a、一低反射率分光鏡2〇4b、以及 一物鏡204d。光學元件組204更可包含一耦合鏡2〇4c，為增 加光輕合效率與調整雷射光源的準直度改變光學倍率，其可 依使用時的需求做增加或拆除。 雷射二極體組203發出一雷射光源λΐ，並穿透光柵204a 後’經由低反射率分光鏡204b作反射，其一次反射光205a 再穿透耦合鏡204c與物鏡204d並投射於記錄媒體201，進 行讀取或寫入資料的動作《從記錄媒體201反射的雷射光依 序穿透物鏡204d、耦合鏡204c，並在低反射率分光鏡204b 作反射與穿透。反射自低反射率分光鏡204b的光束為二次反 射光205b，其回饋至雷射二極體組203。由於雷射光源λΐ經 過低反射率分光鏡204b的兩次反射作用後的二次反射光 205b回饋至雷射二極體組203時，二次反射光205b不會對 雷射二極體產升相對強度雜訊的問題。當雷射光源為λ2及λ3 時，同理亦同。 記錄媒體201利用雷射二極體組203發射之雷射光源λΐ 來讀取或寫入資料，光訊號檢出器202接收記錄媒體201反 射之雷射光205c，並偵測雷射光205c訊號的強弱。將光訊 號檢出器202以傾斜3°至15°的0角設置於一光軸30的下 方’因此當雷射光205c抵達光訊號檢出器202的同時，雷射 光205c會在光訊號檢出器202以一特定角度反射為反射光 205d，同樣的雷射光205cl、205c2會在光訊號檢出器202反 射為反射光205dl、205d2。由於光訊號檢出器202與光軸30 M3791.45 為傾斜3°至15°，所以此0角使反射光205d、205dl、205d2 的行徑方向偏離雷射光源的方向，其有效的阻絕反射光 205d、205dl、205d2會回饋到雷射光源，進而有效解決回饋 干擾的問題。 請參考第三圖，第三圖為本創作所使用低反射率分光鏡 的光學效率之示意圖。第三圖之橫轴代表分光鏡之反射率， 影響物鏡出光量大小。線型41代表反射一次穿透一次之光學 效率’影響光訊號檢出器之光量大小；反射率在5〇%時，其 效率最大，只達到25%。線型42代表反射兩次之光學效率， 影響反饋至雷射二極體組之雜散光大小；其效率能夠達到 100% ;在較低的反射率時，可得更低的反射兩次效率。 惟，以上所述者，僅為本創作之例舉實施例而已，當不 、匕限疋本創作貫施之範圍。即大凡依本創作申請專利範 圍所作之均等變化與修飾，㈣仍屬本_專利涵蓋之範圍 内。 8 M3.791.45 【圖式簡單說明】 第-關習知絲讀寫顿構之示意圖。 第二圖為本創作光學讀寫頭結構之示意圖。 第三圖為本創作所使用低反射率分光鏡的效率之示意圖。 【主要元件符號說明】 101 記錄媒體 — 102光訊號檢出器 103雷射二極體組(DVD, CD) ----- 104分光鏡 l〇4a光柵 105準直透鏡 106物鏡 105c DVD反射光 105d CD反射光 201記錄媒體 202光訊號檢出器 203雷射二極體組 204光學元件組 204a光柵 204b低反射率分光鏡 204c耦合鏡 204d物鏡 205a —次反射光 205b二次反射光 205c λΐ雷射光 205cl λ2雷射光 205c2 λ3雷射光 205d λΐ反射光 205dl λ2反射光 205d2 λ3反射光 M379145 » . * 30光轴 41線型 42線型Disk 'DVD', high-density digital video disc hd_dvd, BD-DVD has been widely used in the life of enterprises, families and individuals, so the relevant industry is committed to developing more efficient reading or recording technology. To improve the quality of recording media such as CDs, VCDs and _s, HIH) VD, BD-DVD. The recorded media is read or written by the optical pickup through the recording medium. The light source emitted by the laser diode group is focused on the surface of the recording medium through the optical element group to read or write data, and then the optical signal detector receives or detects the reflected strong signal. Please refer to the figure - the first figure is a schematic diagram of the structure of the conventional optical head. The optical pickup structure includes a recording medium 101, an optical detector 102, a laser diode set 103, a beam splitter 104, a collimating lens 1〇5, and an objective lens 106. The DVD or CD laser light source emitted by the laser diode group 103 first penetrates the optical head 104a, is reflected by the beam splitter 104, passes through the collimating lens 105 and the objective lens 1〇6, and is focused on the recording medium. The surface of 101 performs an action of reading or recording data. The laser light source is reflected by the surface of the recording medium 1〇1, passes through the objective lens 106 and the collimating lens 105, and is divided into two parts by the beam splitter 104, and a part is penetrated, and is detected by the beam splitter 1〇4 to the optical signal. On the device 102, the detection action of the strong and weak signals is performed. The other part is reflected by the beam splitter 104, penetrates the grating 104a, and enters the laser diode group 103, causing the laser diode group 103 to generate a relative intensity noise problem. The optical mirror 104 of the optical head For the purpose of achieving higher optical efficiency, the reflectance is usually between 35% and 85% 'to achieve the optical efficiency of one reflection, two reflections and one reflection at a time. However, it is easy to cause a large increase in the amount of backscattered light from the recording medium to the reflected light. Please refer to the line type 42 of the third figure, resulting in a relative intensity noise problem for the laser. This part is the main source of relative intensity noise for the laser diode group 103. In the above, the same reflected light 105c, 105d reflected by the surface of the optical signal detector 102 may pass through the beam splitter 1〇4' collimating lens 1〇5 and the objective lens 106, and then focus on the recording medium 1〇1 again. The surface is then guided through the objective lens 106, the collimating lens 1〇5, and the beam splitter 1〇4 to the laser diode group 1〇3, which causes a relative intensity noise problem to the laser. This part is the main source of the relative intensity noise of the laser diode group 1〇3. M379145 » , 1 [New content] The main purpose of this creation is to reduce or solve the problem of relative intensity noise generated by the laser diode due to the feedback light of the recording medium. For the purpose of the foregoing, the present invention proposes an optical read/write head having a low reflectivity spectroscope having an average reflectance of 10% to 30%, comprising a laser diode set, an optical component group, and a Recording media, an optical signal detector. The laser source emitted by the laser diode group is reflected and penetrated by the optical component group and focused on the surface of the recording medium for reading or writing data, and then reflected from the surface of the recording medium. The component group is directed to the optical signal detector to detect strong and weak signals. Since the optical signal detector is tilted by 3 with an optical axis. The angle is set to a 0° angle of 15°. Therefore, the optical signal detector can directly reflect the incoming laser light into reflected light, so that the reflected light is not fed back to the laser light source of the laser diode. The optical component group includes a grating, a low reflectivity beam splitter, and an objective lens. The grating divides the 1 beam into 3 beams, and the low reflectivity beam splitter has the function of reflecting and transmitting the transmitted laser light, and the objective lens is used to focus the laser light. The optical component group further includes a coupling mirror that changes the optical magnification for increasing the optical coupling efficiency and adjusting the collimation of the laser light. This creation uses a low-reflection spectroscope with a reflectivity of 10% to 30% and a reflection of the laser light twice to reduce the relative intensity of the aforementioned laser diode 103. Main source 1 'plus optical signal The output and the optical axis are inclined at a 0-to-15 angle of 0 to 15 to reduce the relative intensity of the aforementioned laser diode. The main source of noise 2' enables the optical read/write head of the present invention to reduce or eliminate the laser diode. The purpose of the relative intensity of noise generated by the recording media feedback light. The low reflectivity beam splitter used in the optical read/write head of the present invention has a low cost and tilts the optical signal detector to the optical axis. To 15. The 0 corner setting is the advantage of the technology. The combination of the two can effectively reduce or eliminate the feedback light, and solve the long-term problem of the relative intensity noise of the laser diode, so this creation can enhance the competitiveness of the industry in optical head products. And the advantages of enhanced products. The above and other objects and advantages of the present invention will be described in detail below with reference to the accompanying drawings. [Embodiment] Please refer to the second figure. The second figure is a schematic diagram of the structure of the optical head. The optical pickup structure includes a recording medium 2, an optical signal detector 202, a laser diode group 203, and an optical element group 204. The laser diode set 203 can be a single wavelength or a two or three wavelength laser source. The optical element group 204 includes a grating 204a, a low reflectivity beam splitter 2〇4b, and an objective lens 204d. The optical component group 204 further includes a coupling mirror 2〇4c for changing the optical light combining efficiency and adjusting the collimation degree of the laser light source to change the optical magnification, which can be added or removed according to the requirements of use. The laser diode group 203 emits a laser light source λ ΐ and passes through the grating 204a and is reflected by the low reflectivity beam splitter 204b. The primary reflected light 205a passes through the coupling mirror 204c and the objective lens 204d and is projected onto the recording medium. 201. Performing an operation of reading or writing data "The laser light reflected from the recording medium 201 sequentially penetrates the objective lens 204d, the coupling mirror 204c, and reflects and penetrates at the low reflectivity beam splitter 204b. The light beam reflected from the low reflectance beam splitter 204b is the secondary reflected light 205b, which is fed back to the laser diode group 203. Since the secondary reflected light 205b of the laser light source λΐ after the two reflections of the low reflectance beam splitter 204b is fed back to the laser diode group 203, the secondary reflected light 205b does not rise to the laser diode. The problem of relative intensity noise. When the laser source is λ2 and λ3, the same is true. The recording medium 201 reads or writes data by using the laser light source λ 发射 emitted by the laser diode group 203, and the optical signal detector 202 receives the laser light 205c reflected by the recording medium 201, and detects the intensity of the laser light 205c. . The optical signal detector 202 is disposed below the optical axis 30 at a 0 angle of 3° to 15°. Therefore, when the laser light 205c reaches the optical signal detector 202, the laser light 205c is detected at the optical signal. The reflector 202 is reflected as reflected light 205d at a specific angle, and the same laser light 205cl, 205c2 is reflected by the optical signal detector 202 as reflected light 205dl, 205d2. Since the optical signal detector 202 and the optical axis 30 M3791.45 are inclined by 3° to 15°, the 0 angle makes the direction of the reflected light 205d, 205dl, and 205d2 deviate from the direction of the laser light source, and effectively blocks the reflected light. 205d, 205dl, 205d2 will feed back to the laser source, which effectively solves the problem of feedback interference. Please refer to the third figure. The third picture is a schematic diagram of the optical efficiency of the low reflectivity beamsplitter used in the creation. The horizontal axis of the third graph represents the reflectivity of the beam splitter, which affects the amount of light emitted by the objective lens. The line type 41 represents the optical efficiency of the reflection once penetrated, which affects the amount of light of the optical signal detector; when the reflectance is 5〇%, the efficiency is the highest, only 25%. Line type 42 represents the optical efficiency of two reflections, affecting the amount of stray light fed back to the laser diode group; its efficiency can reach 100%; at lower reflectance, lower reflection efficiency can be obtained twice. However, the above-mentioned ones are only examples of the present invention, and are not limited to the scope of the present creation. That is to say, the equal changes and modifications made by Dafan in accordance with the scope of patent application for this creation, (4) are still within the scope of this patent. 8 M3.791.45 [Simple description of the diagram] The first-off schematic diagram of the reading and writing of the silk. The second figure is a schematic diagram of the structure of the optical head. The third figure is a schematic diagram of the efficiency of the low reflectivity beamsplitter used in the creation. [Main component symbol description] 101 Recording media - 102 optical signal detector 103 laser diode set (DVD, CD) ----- 104 beam splitter l〇4a grating 105 collimating lens 106 objective lens 105c DVD reflected light 105d CD reflected light 201 recording medium 202 optical signal detector 203 laser diode group 204 optical element group 204a grating 204b low reflectivity beam splitter 204c coupling mirror 204d objective lens 205a - secondary reflected light 205b secondary reflected light 205c λ ΐ ΐ Light 205cl λ2 laser light 205c2 λ3 laser light 205d λΐ reflected light 205dl λ2 reflected light 205d2 λ3 reflected light M379145 » . * 30 optical axis 41 line type 42 line type