200903473 九、發明說明： 【發明所屬之技術領域】 本發明係關於光學資料儲存祕，且更特定言之係關於 -種用於掃描儲存在具有多個資訊層之光學記錄載體上之 資料的設備及光學掃描裝置。 【先前技術】 光學資料儲存系統(即光學記錄系統或光學資料驅動器) 提供構件，用於在一光學記錄載體（例如光碟）上儲存大量 資料。一在光學資料驅動器内的光學掃描裝置係用於掃描 該等载體之-或多個資訊層。各種光學資料儲存媒體格式 及系統係為人熟知並已普遍使用，例如根據CD及dvd媒 體標準之媒體，用於僅從預記錄資料（例如r〇m或視訊）讀 取貝料，或用於在可記錄或可重寫媒體（例如cD_R、 DVD+R、DVD-R 或 CD-RW、DVD+RW、DVD-RW ' DVD- RAM)上記錄資料。 具有約650 MB至700 MB之容量的CD媒體，係可使用一 半導體雷射（其發射波長約78〇 nm之一輻射束）及一具有 0.45至約〇·55的數值孔徑（NA)之物鏡來記錄且讀取。該資 料係透過1.2 mm厚度的一標準透明層讀取及/或寫入。 使用一半導體雷射（其發射一具有約為65〇 nmi長的輻 射束（DVD^射束））及一物鏡（其具有〇 6〇至約〇 652nA)， 可。己錄並可讀取容量約4.7 〇0的DVD媒體。光碟之 标準透明層厚度係〇·6 mm。為了增加此媒體之總容量，另 外已引入雙資訊層光碟用於DVD唯讀及可記錄媒體，其容 129107.doc 200903473 量約為單一資訊（資料）層光碟的兩倍。在雙層DVD光碟之 兩個資訊層間之間距係約5 5 μηι。 針對根據藍光光碟（BD)標準之新媒體類型光學記錄載體 之一最近引入的較高容量標準光學記錄載體具有每層約 25 GB之容量。所應用的輻射束之標準波長係約4〇5 nm而 將輻射束聚焦在資訊層上的物鏡之標準NA係約〇·85。輻射 束係透過0.1 mm厚度之標準透明覆蓋層來聚焦。鑑於甚至 較咼資料儲存容量需求，BD亦包括一雙層光碟，其容量 為5 0 G B。此雙層b D光碟之兩個資訊層間的間隔係約 25 μηι。對於甚至較高容量需求亦多於兩個資訊層之需求 係正運作中。 應瞭解，一光學記錄載體之一資訊層可為一預記錄資訊 層，例如用於資料分布 '視訊分布等；或一可記錄資訊 層，例如用於資料及/或視訊記錄。掃描一資訊層可視為 表示在此一資訊層上讀取及/或記錄（例如）資料。 隨著容量需求增加，光碟上資料結構（位元）之尺寸係由 CD降低至DVD至BD。此係（例如）藉由應用輻射束之波長 的減少，及從CD至DVD至BD.統增加物鏡的^^八來實現。 掃描點尺寸與λ/ΝΑ成比例，因此掃描點尺寸從cd系統中 的約1.5 ’減小至DVD系統中的約i 〇叫至肋***中的約 0.48 μιη。為了產生一足夠光學品質的賴射點’在光學資 料驅動器中的光學掃描裝置需要至少聚焦及循執控制，以 在軸向（垂直於光碟表面）之磁軌上以及在徑向（垂直於磁執 並在光碟平面内）中保持掃描點。例如’從磁軌及最佳聚 129107.doc 200903473 焦位置偏差可能會在記 品質降低。 』間導致重製資料或離軌資料之 一為人熟知聚焦方法之一筋 靶例係散光聚焦方法。然而， =應用其他聚焦方法，例如刀口(傅科；F_auh)聚焦 ^或點大小_聚焦方法°對於”循執方法，亦有一 些為人熟知可能性，例如抽 缸士<+ +、 〗如推挽循軌方法、三束（或三點）循 軌方法或差分推挽循軌方法。 用於可記錄光碟系統之聚焦及循執方法之一常用組合係 散光聚焦方法連同三點差分推挽循軌方法。例如，一圓柱 形透鏡及/或平面平行板可用於在朝向㈣_器之輕射 束内產生用於散光聚焦方法之散光。可應用一繞射光栅以 從輻射源(例如半導體雷射)發射之輻射束中產生一主輻射 束及兩輔助輻射束。-用於主幸畐射束之強度相對於各輔助 束内之強度的常用強度比係約為1〇比15，對於可記錄*** 超過1，但可具有一不同比。在應用中於該主束中之一高 韓射功率位準對於記錄速率較為有利。 门 適用於配合該散光聚焦三點差分推挽循轨方法的一㈣ 偵測器幾何形狀，包含—主偵測器及兩輔助偵測器㈠目對 於該主偵測器彼此相對）。 光碟内資訊層所反射之主轄射束係經由物鏡投射在主债 測器上，其係用於產生資料讀取信號（資料信號）。該主偵 測器亦通常係分成四個象限片斷（相對於光碟上之磁軌對 應於一徑向及一切線方向）以可基於該散光方法產生一聚 焦誤差信號。資訊層所反射之輔助束各係經由物鏡而投射 129107.doc 200903473 至辅助偵測器之一上。夂 ^ μ 各輔助偵測器係分成兩片斷（相對 於先碟上之磁軌對應於徑 ’ 以月匕為母一輔助束產生一 推挽化號。藉由組合主彳貞 、測°。及兩輔助偵測器之該等推挽 1吕號，可產峰_ —机¥ 、 % ^ 二2差为推挽信號作為徑向循執誤差信 …亥聚焦决差仏虎及徑向循軌信號係用於飼服控 器件以在轉描之料±精確㈣準掃描點。200903473 IX. DESCRIPTION OF THE INVENTION: TECHNICAL FIELD OF THE INVENTION The present invention relates to optical data storage and, more particularly, to an apparatus for scanning data stored on an optical record carrier having multiple information layers. And optical scanning device. [Prior Art] An optical data storage system (i.e., an optical recording system or an optical data drive) provides a means for storing a large amount of data on an optical record carrier such as a compact disc. An optical scanning device within the optical data drive is used to scan the carrier's - or multiple information layers. Various optical data storage media formats and systems are well known and commonly used, such as media based on CD and DVD media standards, for reading bait only from pre-recorded material (eg, r〇m or video), or for Record data on recordable or rewritable media (eg cD_R, DVD+R, DVD-R or CD-RW, DVD+RW, DVD-RW 'DVD-RAM). A CD medium having a capacity of about 650 MB to 700 MB can use a semiconductor laser (having a radiation beam having a wavelength of about 78 〇 nm) and an objective lens having a numerical aperture (NA) of 0.45 to about 55 Å. To record and read. The material is read and/or written through a standard transparent layer of 1.2 mm thickness. A semiconductor laser (which emits a radiation beam (DVD beam) having a length of about 65 〇 nmi) and an objective lens (having 〇 6 〇 to about 652 652 nA) are used. It has been recorded and can read DVD media with a capacity of about 4.7 〇0. The standard transparent layer thickness of the disc is 〇·6 mm. In order to increase the total capacity of this media, dual-information optical discs have been introduced for DVD-reading and recordable media, and the volume of 129107.doc 200903473 is about twice that of a single information (data) layer. The distance between the two information layers of the dual-layer DVD disc is about 5 5 μηι. The higher capacity standard optical record carrier recently introduced for one of the new media type optical record carriers according to the Blu-ray Disc (BD) standard has a capacity of approximately 25 GB per layer. The standard wavelength of the applied radiation beam is about 4 〇 5 nm and the standard NA system of the objective lens that focuses the radiation beam on the information layer is about 〇·85. The radiation beam is focused through a standard transparent overlay of 0.1 mm thickness. In view of the data storage capacity requirements, BD also includes a double-layer disc with a capacity of 50 G B. The interval between the two information layers of the double-layer b-disc is about 25 μηι. The demand for more than two information layers for even higher capacity requirements is in operation. It should be understood that an information layer of an optical record carrier can be a pre-recorded information layer, for example for data distribution 'video distribution, etc.; or a recordable information layer, for example for data and/or video recording. Scanning an information layer can be viewed as indicating reading and/or recording (e.g., data) on this information layer. As capacity requirements increase, the size of the data structure (bits) on the disc is reduced from CD to DVD to BD. This is achieved, for example, by applying a reduction in the wavelength of the radiation beam and increasing the objective lens from CD to DVD to BD. The scan spot size is proportional to λ/ΝΑ, so the scan spot size is reduced from about 1.5 ′ in the cd system to about i 〇 in the DVD system to about 0.48 μηη in the rib system. In order to produce a sufficient optical quality of the viewing point' optical scanning device in the optical data drive requires at least focus and control, on the magnetic axis in the axial direction (perpendicular to the surface of the optical disk) and in the radial direction (perpendicular to the magnetic Keep scanning points in the plane of the disc. For example, the deviation from the magnetic track and the optimal poly 129107.doc 200903473 focal position may be degraded. One of the fascinating methods is the astigmatism focusing method. However, = apply other focusing methods, such as knife edge (Fouco; F_auh) focus ^ or point size _ focus method ° For "circular methods, there are some well-known possibilities, such as pumping tanks + +, 〗 Such as push-pull tracking method, three-beam (or three-point) tracking method or differential push-pull tracking method. One of the commonly used combinations of focusing and circulatory methods for recordable optical disc systems is the astigmatism focusing method together with three-point differential pushing. A tracking method. For example, a cylindrical lens and/or a plane parallel plate can be used to generate astigmatism for the astigmatic focusing method in a light beam toward the (four) _. A diffraction grating can be applied to extract from the radiation source (eg A semiconductor laser emits a main radiation beam and two auxiliary radiation beams. The common intensity ratio of the intensity of the main fortunate beam relative to the intensity of each auxiliary beam is about 1 to 15, For a recordable system more than 1, but can have a different ratio. In the application, one of the main bundles has a high Korean power level which is advantageous for the recording rate. The gate is suitable for the astigmatism focusing three-point differential push-pull tracking One (four) of the method The detector geometry includes a main detector and two auxiliary detectors (one) for which the main detector is opposite to each other. The main beam reflected by the information layer in the optical disc is projected on the main debt detector via the objective lens. In the above, it is used to generate a data read signal (data signal). The main detector is also generally divided into four quadrant segments (relative to the radial and all line directions of the magnetic track on the optical disc) to be based on The astigmatism method generates a focus error signal. The auxiliary beam reflected by the information layer projects 129107.doc 200903473 through the objective lens to one of the auxiliary detectors. 夂^ μ Each auxiliary detector is divided into two segments (relative to The magnetic track on the first disc corresponds to the diameter 'to generate a push-pull number with the auxiliary beam as the mother beam. By combining the main 彳贞, measuring °, and the two auxiliary detectors, the push-pull 1 Lu, Can produce peak _ — machine ¥ , % ^ 2 2 difference for push-pull signal as radial circumstance error letter... Hai focus decision 仏 tiger and radial tracking signal is used for feeding control device to transfer material ± Accurate (four) quasi-scanning points.
八多層光碟包含資訊層之堆疊；資訊層係藉由-間隔件層 77離。此一多層光碟之範例係雙層BD，其包含兩資訊層 及L0之堆疊，其藉由—約25叫之間隔件層分離及藉 由一 0.075 mm厚度之透明覆蓋層（一單一層⑽光碟具有— 一 mm厚度之透明覆蓋層）整體覆蓋。可假定Μ係最靠近 光碟輻射入射表面，同時假定L〇係更遠離該光碟輻射入射 表面。L1係不完全反射，由於較佳係掃描l〇層以使用此第 一資Λ層之容量。因此，當掃描L丨資訊層時，一些輻射會 朝向L0貝汛層透射並反射回到物鏡内以投射向該輻射偵測 器。當掃描L〇資訊層時，L1資訊層亦反射一些輻射，其投 射向輻射偵測器。在兩情形下，此等額外反射輻射束可能 在主偵測器及辅助偵測器上造成不需要的輻射發生，其可 旎在與掃描資訊層有關的偵測器上與反射主束及輔助束之 輕射點造成光學干擾。 田在L 0與L1間之間隔物層在例如沿磁執及/或垂直於磁 軌方向中之厚度變化時，所產生之干擾圖案亦隨之變化， 因而造成串擾，即所謂同調串擾。結果此串擾可能會擾亂 聚焦及/或循軌誤差信號或資料信號，其可能導致不正確 129107.doc 200903473 循執、聚焦及/或資料記錄或資料再生。 由於在該等輔助偵測器上所投射的辅助束之強度在可記 錄系統内係比在主束内的強度低許多，該串擾在循軌誤差 信號（例如推挽信號）上之影響可大得使掃描雙層媒體變得 不穩定。 本發明之目的係提供一種光學掃描裝置，其中伺服信號 上之層間串擾係予以減少。 ~ 【發明内容】 本發明之目的係藉由提供—種用於掃描—光學記錄載體 之光學掃描裝置獲得，該光學記錄載體具有多個資訊層， 該裝置具有一輻射源，其係用於產生一輻射束；一繞射構 件，其係用於自該韓射束藉由一繞射圖案產生一零階轄射 束及至少兩較高階繞射㈣束’纟中該光學掃描裝置包含 -相位調變構件，錢配置以在該至少兩較高階繞射韓射 束及該零階輻射束間產生一相位調變。 藉由引入在配置以產生一在該至少兩較高階繞射韓射束 (如正及負第-階繞㈣射束）亦稱為輔助束）及該零階轄射 束間之相位調變的光學掃描裝置中之相位調變構件，在飞 _測器上之兩反射較高階繞射輕射束及由在該輕射： 測器上之此其他資訊層反射的該零階輕射束間之 變。此導致在該干擾圖案之時間中的平均，減少由於^ 串擾在伺服信號中之失真。 根據本發明之一態樣，該相位調變構件經配置以調變缺 射構件之該繞射圖案的位置。藉由調變該繞射㈣之: 129107.doc 200903473 置’該兩反射較高階繞射輻射束之 輕射束之相位保持不受影響。 &被調變’而該零階 可係(例如):繞射光柵，如用於產生 此繞射光柵可在定位，調變，其宜係 光栅、_ ! 繞射圖案之方向巾，該繞射圖案可由 先柵溝槽組成。與垂直方向之 差4大，位置的調變效率 愈低，且因此減少層間串擾之效率愈低。 =位調變構件可包含一位移構件，其係用於位移該繞 :光柵，如一壓致動器或-電磁致動H，其係用於調變該 、堯射光柵之該繞射圖案的位置。該位移構件宜經配置以實 質上垂直於該繞射光柵之光栅溝槽位移該繞射光柵。 本發明之另-態樣係藉由—光學掃描裝置提供，其中該 繞射構件包含該相位調變構件且宜係形成為一件。使用此 =整合式裝置，成本可減少且該裝置之大小整體而言可減 少。此一整合式繞射及相位調變構件之範例係一聲光調變 器或一電光調變器。 一聲光調變器可經調適以產生一繞射圖案，以及可產生 一在該至少兩較高階繞射輻射束及該零階輻射束間之相位 調變。此亦將在從被掃描之該資訊層反射的該等較高階繞 射輕射束及由除了被掃描之該層以外的另_資訊層反射的 該零階輻射束之間，導致一相位調變。在晶體中傳播之聲 波會在晶體中產生一壓力波，其引發一折射率調變，因此 —繞射圖案或光柵圖案，該圖案將會在晶體中移動（由於 S亥傳播聲波）因而調變該等較高階繞射輻射束之相位。 129107.doc -11 - 200903473 相位調μ構件亦可為—電光調變器m調變器可包 含：液晶材料，及-圖案化電極組態，其係用於產生-繞 射光柵以&纟0亥至少兩較高階繞射輻射束及該零階輻射 束門之相位凋變。一供應至該電光調變器之一圖案化電極The eight-layer optical disc contains a stack of information layers; the information layer is separated by a spacer layer 77. An example of such a multilayer optical disc is a two-layer BD comprising a stack of two information layers and L0 separated by a spacer layer of about 25 and covered by a transparent cover layer of a thickness of 0.075 mm (a single layer (10) The disc has an overall coverage of - a transparent cover of a thickness of one mm. It can be assumed that the tether is closest to the disc radiating the incident surface, while assuming that the L〇 is farther away from the incident surface of the disc. L1 is incompletely reflective, since it is preferred to scan the layer to use the capacity of this first layer of credit. Therefore, when scanning the L丨 information layer, some of the radiation is transmitted toward the L0 shellfish layer and reflected back into the objective lens to be projected toward the radiation detector. When scanning the L〇 information layer, the L1 information layer also reflects some of the radiation that is projected onto the radiation detector. In both cases, such additional reflected radiation beams may cause unwanted radiation on the main detector and the auxiliary detector, which may be on the detector associated with the scanning information layer and the reflected main beam and the auxiliary The light beam of the beam causes optical interference. When the spacer layer between L 0 and L1 changes, for example, in the direction of magnetic and/or perpendicular to the direction of the magnetic track, the resulting interference pattern also changes, thereby causing crosstalk, so-called coherent crosstalk. As a result, this crosstalk may disturb focus and/or tracking error signals or data signals, which may result in incorrect circumvention, focus, and/or data logging or data regeneration. Since the intensity of the auxiliary beam projected on the auxiliary detectors is much lower in the recordable system than in the main beam, the crosstalk can have a large influence on the tracking error signal (for example, a push-pull signal). It is necessary to make the scanning double layer media unstable. SUMMARY OF THE INVENTION An object of the present invention is to provide an optical scanning device in which interlayer crosstalk on a servo signal is reduced. SUMMARY OF THE INVENTION The object of the present invention is obtained by providing an optical scanning device for a scanning-optical record carrier having a plurality of information layers, the device having a radiation source for generating a radiation beam; a diffraction member for generating a zero-order beam from the diffraction beam by the diffraction pattern and at least two higher-order diffraction (four) beams of the optical scanning device comprising - phase The modulation component is configured to generate a phase modulation between the at least two higher order diffracted Han beam and the zero order radiation beam. By introducing a phase modulation between the at least two higher order diffraction Han beams (such as positive and negative first-order windings (four) beams), and the zero-order ray beam a phase modulation member in the optical scanning device, the two-reflection higher-order diffracted light beam on the fly detector and the zero-order light beam reflected by the other information layer on the light-emitting detector Change between. This results in averaging over the time of the interference pattern, reducing distortion in the servo signal due to crosstalk. According to one aspect of the invention, the phase modulation member is configured to modulate the position of the diffraction pattern of the missing member. By modulating the diffraction (4): 129107.doc 200903473 The phase of the light beam of the two-reflected higher order diffracted radiation beam remains unaffected. & is modulated 'and the zero order can be (for example): a diffraction grating, such as used to generate the diffraction grating can be positioned, modulated, it is suitable for the grating, _! diffraction pattern direction towel, the The diffraction pattern may consist of a gate trench. The difference from the vertical direction is 4, and the modulation efficiency of the position is lower, and thus the efficiency of reducing interlayer crosstalk is lower. The position modulation member may comprise a displacement member for displacing the winding: a grating, such as a pressure actuator or an electromagnetic actuation H, for modulating the diffraction pattern of the radiant grating position. The displacement member is preferably configured to displace the diffraction grating substantially perpendicular to a grating groove of the diffraction grating. Another aspect of the invention is provided by an optical scanning device, wherein the diffractive member comprises the phase modulation member and is preferably formed in one piece. With this = integrated device, the cost can be reduced and the size of the device as a whole can be reduced. An example of such an integrated diffractive and phase modulation component is an acousto-optic modulator or an electro-optic modulator. An acoustic modulator can be adapted to produce a diffraction pattern and to produce a phase modulation between the at least two higher order diffracted radiation beams and the zero order radiation beam. This will also result in a phase shift between the higher order diffracted light beams reflected from the scanned information layer and the zero order radiation beam reflected by the other information layer other than the scanned layer. change. An acoustic wave propagating in a crystal creates a pressure wave in the crystal that initiates a refractive index modulation, and thus—a diffraction pattern or a grating pattern that will move in the crystal (due to the sound wave propagated by S Hai) The phase of the higher order diffracted radiation beam. 129107.doc -11 - 200903473 The phase modulation component can also be an electro-optic modulator m modulator can comprise: a liquid crystal material, and a patterned electrode configuration, which is used to generate a diffraction grating & At least two higher order diffracted radiation beams and phase fading of the zeroth order radiation beam gate. a patterned electrode supplied to one of the electro-optic modulators
的如成為-調變電壓或電流）可在不影響該零階轄 射束下，於5亥專繞射輕射击Φ洋Λΐ* I ^ Μ ^射果中產生一相位調變。該相位調 變宜使振幅係實質上^ ’導致似乎係平均掉在被掃描之 該資訊層反射的該等較高階繞射輻射束及由除了被掃描之 該層以外之另—資訊層反射之該零階輕射束之間之該偵測 器上的該干擾圖案。 用於在光予3己錄載體上讀取及/或寫入資料（例如立 訊：視訊及/或電腦資料)之光學資料驅動器，由於減少： 服U中之串’包含根據本發明之此—光學掃描裝置將 、 在八有夕於資讯層之記錄载體上的更佳讀取及/ ，寫入性能。所得之更穩定㈣信號將改進光學資料驅動 。器的循軌(以及聚焦)特性。較佳係，在此一光學資料驅動 器t ’該等較高階繞射輕射束之相位調變的頻率係大於推 挽飼服電子器件之伺服迴路頻寬。 此外，本發明提供一種減少伺服信號中串擾之方法，★亥 等伺服信號可自-用於掃描—具有多織訊層之^學崎 載體的光學掃描裝置獲得，#由應用—包含—用於產生一 輻射束之輻射源的光學掃描裝置’該輻射束具有_相位， 及一繞射構件，其係用於自該轄射束產生一零階輕射束及 至少兩較高階繞射輕射束’其中該方法包含產生—在自被 129107.doc 200903473 μ之m層反射的該至少兩較高階繞射輕射束，及除 了：掃描之該資訊層以外的另一資訊層反射之該零階輕射 果間的相位調變之步驟。 、較佳係，該方法亦包含以—比推挽伺服電子器件之飼服 坦路頻寬更高的頻率，設定該等較高階繞射輻射束之該相 :調變的頻率之步驟。對於具有各種掃描速率設^之光學 資料驅動器’該伺服迴路頻寬可經調適至該掃描速率，其 允泎-使該串擾減少最佳化之相位調變頻率的後續調適。 參考隨附圖式及下面說明的具體實施例將會明白及說明 本發明的該些及其他態樣。 【實施方式】 、圖1顯不—光學掃描裝置1之範例的示意性設置，其係用 於知描-根據先前技術而無根據本發明之任何慮波構件的 多資訊層記錄載體i 5 (例如B D)。一轄射源i 〇 (如半導體雷 射）七射軲射束1 7。一分光器1 2將輻射束反射朝向一準 直儀透鏡13，其將輕射束準直成—藉由物㈣聚焦至—光 學記錄載體15之資訊層（在此圖中之層u)上的平行轄射 束物鏡可為-單-透鏡或多個透鏡之物鏡。光學掃描裂 置可包含其他光學組件，例如一四分之—波板或一感測器 透鏡，但此等未在圖！中顯示。由資訊層Ll反射之輻射被 反射回進入光學器件及在偵測器上成像（或投射）。層l 1之 知描可藉由使用為人熟知之聚焦及循軌誤差方法（例如散 光聚焦方法及推挽循軌方法）的聚焦輻射束，及相關伺服 控制及致動器(未顯示），其係用於相對於資訊層上的磁軌 129107.doc -13- 200903473 致動（m°)物鏡及/或光學掃描裝置來進行。此範例中的分 光裔12在輪射束19中朝向輕射偵測器⑽生散光。當應用 另類型分光器（如稜鏡類型或繞射類型）時散光必須藉由 #他構件引入，例如一額外圓柱形透鏡或一散光引入繞射 光學結構。 田L 1資纸層係透射朝向未被掃描之另一層l〇的聚焦輻射 束之。卩分日守，L0會將一些輻射18反射回到該光學器件内。 (光學系統亦將此反射輻射朝輻射偵測器16成像（或投射）。 由於此輻射離開物鏡之焦點，該輻射係在輻射偵測器表面 上成像為一大輻射點。 圖2a示思性顯示在用於掃描關於圖1所述之L1的情況中 之偵測器16上的輻射分布。輻射點2〇係在L1點上之輻射掃 描點，其係藉由光學器件投射在一用於根據已知方法聚焦 块差（FE)信號產生及尺以言號產生之象限偵測器22上。對於 一單點推挽散光循軌方法，可應用用以從偵測器22之主偵 I; 測器元件組A、B、C及D導出FE、RF及RE信號之下列方程 式： FE=(A+C)-(B+D) ' rf=a+b+c+d ' 循軌誤差（RE)信號可如下藉由該推挽方法產生 RE=(A+B)-(C+D) 輻射點2 1係未被掃描之另一層（在此情況下為L〇)所反射 之輕射的影像。雖然圖2中為了方便繪有一圓形，輻射點 21之實際形狀可具有一不同形狀，然而，此係不視為與本 129107.doc 200903473 發明有關。 輻射點20與輕射點21之重疊部分將 該+70于十擾’其當 圖木由於（例如）層1^1與1^〇間之間 波動時，A μ、“ 1干層厗度變化而 /、了肖b造成FE、RE及RF信號波動。 "σΓ 00 白，以上問題不限於僅具有兩個資訊 記錄载體。 心饵彳田元予 如/亦在圖1中顯示，係可於光學掃描裝置！中應用三束中 ::徑循執方法或三束推挽循軌方法。對於輻射束17係藉 Τ繞射構件（例如—繞射光栅U)分成-主韓射束及兩辅 助輻射束成為零階輻射束及兩較高階繞射輻射束。較高階 繞射轄射束可為+1及]繞射階束’然而，亦可能其係其他 繞射階輻射束。亦可能使用多於兩個較高階繞射輻射束， 例如+1/_1及+3M繞射階輻射束（如為了更複雜循軌目的）。 主輻射具有比該兩輔助輻射束更大的輻射強度。在適用於 記錄資料之光學掃描裝置中的強度之常用比為i : ι〇:【或 1 . 15 . 1。然而，亦應用其他比。根據相對於資訊層上的 磁軌之習知方法、方位及位置，該三輻射束係聚焦於被掃 描之資訊層上成為主點及第一及第二輔助點。三反射輻射 束係藉由光學系統朝向輻射偵測器成像（或投射），且成像 (參見圖2a)至偵測器元件22、25及26之個別組上，成為一 主20、第一 23及第二24輔助點。輔助偵測器25及26可各分 開使二束推挽循軌可行。可藉由以下方程式使用該等第一 及第二輔助偵測态之第一及第二組偵測器元件E、F、G及 Η來說明基於二束中央孔徑方法之循軌誤差信號： 129107.doc •15- 200903473 rE3sPca = (E + F)-(G+H) 田使用s亥二束推挽循軌方法時，可藉由如下方 明該循軌誤差信號 RE3sppp = [(A+B)-(C + D)]-Kpp.(E-F) + (G-H)] 其中Kpp係在電子器件中的一增益因子，其係用於補償 在該偵測器上的主點及輔助點間之輻射強度差。 輻射點21與輔助點23及24之重疊部分亦將顯示光學干 擾，當該干擾圖案由於（例如）層L丨與L〇間之間隔件層厚度 變化而波動時，其可能造成RE信號波動。 未掃描之層亦會部分反射在被掃描之資訊層上聚焦的辅 助束，且0而亦將在各組之债測器元件上導致一類似於輕 射點21之較大點。然而，由於此等辅助束内的強度通常係 比。亥主輻射束内的強度小許多，故由於光學干擾之擾亂要 小得多且不會造成待解決的主要問題。 在圖2b中干擾圖案係顯示為如在一電腦模擬中所計 算。為了方便，輔助點及由不被掃描之資訊層反射的零階 束的輻射分布間之重疊區域係選定為一方形。 在輔助點中計算之干擾圖案係用於一 25〇〇〇叫(左邊）及 Α065 μηι(右邊）之間隔件厚度。灰色區域係表示用於伯測 器的總表面。可見到所有邊緣對於25 〇〇〇 _間隔件係白 色，而對於25.065 μΓη間隔件係黑色。因此，—僅65 nm之 門之件厚度變化可能已在干擾圖案中造成大變化。此亦 ㈣響欲從_系統獲得之飼服信號，如例如三束推挽信 號。測量已顯示在典型雙層BD光碟上，在圓周上至 129107.doc 200903473 300 nm之間隔件厚度中的變化係屬通常。此意謂著當掃描 此類雙層BD光碟時，可預期推挽信號中之大變化。 熟習此項技術人士會明瞭該情況將類似於—掃描具有多 於兩個資訊層之光學記錄載體的光學掃描裝置。 在習知光學掃描裝置中，繞射光柵之繞射圖案位置係空 間上固定的。在根據本發明之—具體實施例的光學掃描裝 置中’繞Μ目帛係相對於轄射束之光學路徑於其位置中調 變。藉由移動'繞射圖f，繞射輻射束之相位將改變，但; 影響零階輪射束的相位。 在藉由Μ記錄載體反射後，輔助點及來自離焦資訊層 (未被掃描之層）之零階輻射束之反射間的干擾亦將因此= 變相位而調變。光柵χ的位置（具有週期a)決定繞射階 m(|m|>0)的相位Δφ，因此當光栅移動鈥時，爪階之相位 為： △+=2mnAx/a 光柵（即繞射圖案）之移動可機械地完成，例如使用電磁 致動。°、壓致動器（如圖3a相對於3b中顯示）或其他適合之 機械位移構件。 在Q 3 a中 具體實施例之示意圖係顯示一相位調變構 件3〇，其具有附接至壓致動器33之繞射光柵31。在圖讣 中 具體實施例之示意圖顯示一具有一電磁致動器之相 位調變構件30’，該電磁致動器具有一或多數線圈Μ，其協 同一或多個磁鐵35用於光栅31之繞射圖案的位移。光柵係 在Δχ方向中位移。 129107.doc -17- 200903473 較佳係該位移為一週期性位移，因為此限制該裝 由 位移及大小。當位移係垂直於光學掃描裝置之_時= 測器上輔助點之位置未受影響，因此，此係繞射圖案之浐 佳位移方向。通常三束光柵具有直線溝槽且當位移與此= 溝槽實質上垂直時，調變的效應係最佳，其係—優先選 菖（例如）角度係45度時，由於有效Δχ隨著角夕^ 而減乂 ’該效應減少至約70%，然而，其仍可用。取決於 ( 纟光學掃描裝置中之致動器的機械需求，可選擇最適合的 位移角度。相位調變之頻率取決於繞射圖案的位移速率。、 較佳係，相位調變之頻率係大於伺服迴路頻寬以具有輔 1點之相位的足夠大調變頻率，以便平均掉干擾圖案。實 τ 由於（例如）致動器中之功率限制，可限制繞射圖案 之位移速率。為了繞射圖案之高加速度，力需要(及因此 功率）迅速地增加。 由於伺服電子器件之伺服迴路頻寬可取決於系統的掃描 C/ 14率’在掃描期間調變頻率可能需要調適至系統中之不^ 伺服迎路頻寬設定’以致(較佳係”目位調變之頻率係大於 伺服電子器件之伺服迴路頻寬的所應用設定。 、 輔助點之循軌誤差信號無須含有伺服之全頻寬，因為在 - (例士）束著靶（beamlanding)或間隔件層厚度中之變化通常 係相對較低頻率失真。可將主點循軌信號用作高頻變化。 車又佺係，輔助點之相位變化在掃描期間係比束著靶及同 '串擾之預期變化更快速。輔助點之推挽信號將足以補償 束著靶，而同調串擾之作用將被平均。 129l07.doc •18- 200903473 較佳係，可將一低^通遽波器或帶通遽波器用於光學掃描 裝置之飼服迴路電子器件中，以消除由於移動光拇在輔助 點之推挽令的調變。 在另一具體實施例中（如圖4中概要地顯示），根據本發 明:繞射圖案係藉由在具有光聲特性之適合材料42(如一 光聲調變器40)中產生壓力波形成。s力波將引發產生繞 射圖案4:之折射率調變"遺著聲波傳播，圖案將移動(由 圖4中之箭頭方向指示），且此將導致輔助點的相位調變。 聲速及聲波頻率決定圖案的週期。&了可在聲光調變器中 達到料，頻率通常在1()至⑽MHz之量級中（取決於聲光 調變器及使用材料的類型）。需要獲得一具有週期p之繞射 圖案的頻率f係藉由f=v/(p.n)給定，其中聲速後材料之（光 學)折射率η。用於材料參數之典型值係v約3 km/Sh約2， 對於㈣μΓη導致約30廳⑴。如可理解，此等值取決 於用於聲光調變器之材料及獲得繞射輕射束之適當繞射角 度的所需光柵週期。 依此方法，與伺服頻寬（通常在數10 kHz之量級）相比， 繞射圖案移動係足夠快速且干擾圖案將被平均掉。 在本發月又另一具體實施例中，繞射圖案使用如圖5中 枝要地顯v之—具有電光調變材料的t _調變器50產生， 該材料例如〉夜晶材料5 2。繞射圖案係、使用（例如）由透明 1:0材料製成之圖案化電極51產生。藉由在圖案化電極上 電壓可改變圖案的相位深度。藉由（例如）將電壓 自V切換至-V ’繞射圖案可反轉。在一狀態(如具有已施 129107.doc •19· 200903473 加+v)中’與行經其他部分之、' 輻射的相位係提1 ^ h ，通過該等電極之If it becomes a modulated voltage or current, a phase modulation can be generated in the 5 ray-specific diffraction light Φ Λΐ I I I I I I I I 射 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 The phase modulation is such that the amplitude system substantially causes the higher-order diffracted radiation beams that appear to be reflected on the scanned information layer to be averaged and reflected by the other information layer other than the layer being scanned. The interference pattern on the detector between the zero-order light beams. Optical data driver for reading and/or writing data (eg, video: video and/or computer data) on a light-recorded carrier, due to the reduction: the string in the service U contains the invention according to the invention - The optical scanning device will have better read and/or write performance on the record carrier of the information layer. The resulting more stable (four) signal will improve the optical data drive. Tracking (and focusing) characteristics of the device. Preferably, the phase modulation of the higher order diffracted light beams of the optical data driver t' is greater than the servo loop bandwidth of the push-pull electronic device. In addition, the present invention provides a method for reducing crosstalk in a servo signal, and a servo signal such as HM can be obtained from an optical scanning device for scanning a multi-texturing layer, and is used by an application-included An optical scanning device for generating a radiation source of a radiation beam having a phase, and a diffraction member for generating a zero-order light beam and at least two higher-order diffraction light beams from the beam a beam 'where the method includes generating - the at least two higher order diffracted light beams reflected from the 129107.doc 200903473 μm layer, and the zero of the other information layer reflection other than the scanned information layer The step of phase modulation between the steps of the light shot. Preferably, the method further comprises the step of setting the phase of the higher order diffracted radiation beam: the frequency of the modulation, at a frequency higher than the bandwidth of the feeding device of the push-pull servo electronics. For an optical data drive having various scan rate settings, the servo loop bandwidth can be adapted to the scan rate, which allows the crosstalk to be reduced for subsequent adaptation of the optimized phase modulation frequency. These and other aspects of the present invention will be apparent from and elucidated with reference to the appended claims. [Embodiment] FIG. 1 shows a schematic arrangement of an example of an optical scanning device 1 for describing a multi-information layer record carrier i 5 according to the prior art without any wave-wave member according to the invention ( For example BD). A sub-source i 〇 (such as a semiconductor laser) seven-beam beam 1 7 . A beam splitter 12 reflects the radiation beam towards a collimator lens 13, which collimates the light beam into - by means of (4) focusing onto the information layer (layer u in the figure) of the optical record carrier 15 The parallel-beam beam objective can be an objective lens of a single-lens or a plurality of lenses. Optical scanning cracks can include other optical components, such as a quarter-wave plate or a sensor lens, but these are not shown! Shown in . Radiation reflected by the information layer L1 is reflected back into the optics and imaged (or projected) on the detector. The layer 1 can be viewed by a well-known focusing and tracking error method (such as an astigmatic focusing method and a push-pull tracking method), and a related servo control and actuator (not shown). It is used to actuate (m°) the objective and/or optical scanning device relative to the magnetic track 129107.doc -13 - 200903473 on the information layer. The spectator 12 in this example scatters light in the wheel beam 19 towards the light detector (10). When a different type of beam splitter (e.g., helium type or diffraction type) is applied, astigmatism must be introduced by means of a member, such as an additional cylindrical lens or a astigmatism introduced into the diffractive optical structure. The field L 1 paper layer is transmitted toward the focused radiation beam of the other layer that is not scanned. At a time, L0 will reflect some of the radiation 18 back into the optics. (The optical system also images (or projects) this reflected radiation toward the radiation detector 16. Since the radiation leaves the focus of the objective lens, the radiation is imaged as a large radiant point on the surface of the radiation detector. Figure 2a Shown is the radiation distribution on the detector 16 used in the scan for the L1 described with respect to Figure 1. The radiant point 2 is the radiation scan point at point L1, which is projected by the optical device The block difference (FE) signal is generated according to a known method and is generated by the quadrant detector 22. For a single-point push-pull astigmatism tracking method, the main detector I can be applied from the detector 22. The following equations for the FE, RF, and RE signals are derived from the detector component groups A, B, C, and D: FE=(A+C)-(B+D) ' rf=a+b+c+d ' tracking error The (RE) signal can be generated by the push-pull method as follows: RE=(A+B)-(C+D) The radiant point 2 1 is lightly reflected by another layer (in this case, L〇) that is not scanned. The image of the shot. Although the shape of the radiant point 21 may have a different shape in FIG. 2 for convenience, the system is not considered to be related to the invention of 129107.doc 200903473. The overlap between the radiant point 20 and the light-spotting point 21 will be +70 in the ten-disturbing 'When the graph fluctuates between, for example, layers 1^1 and 1^, A μ, "1 dry layer 厗The degree changes and /, the b causes FE, RE and RF signal fluctuations. "σΓ 00 white, the above problem is not limited to only two information record carriers. The heart bait 彳田元予如/also shown in Figure 1, The optical scanning device can be applied to three beams: a diameter tracking method or a three-beam push-pull tracking method. For the radiation beam 17, the diffraction member (for example, the diffraction grating U) is divided into a main Han beam. And the two auxiliary radiation beams become a zero-order radiation beam and two higher-order diffracted radiation beams. The higher-order diffractive beam can be +1 and ] the diffraction order beam. However, it is also possible to use other diffraction-order radiation beams. It is also possible to use more than two higher order diffracted radiation beams, such as +1/_1 and +3M diffraction-order radiation beams (for more complex tracking purposes). The main radiation has a larger radiation than the two auxiliary radiation beams. Strength. The common ratio of intensity in an optical scanning device suitable for recording data is i : ι〇: [or 1.15. 1. However, Other ratios are also applied. The three radiation beams are focused on the scanned information layer to become the main point and the first and second auxiliary points according to the conventional method, orientation and position of the magnetic track on the information layer. The radiation beam is imaged (or projected) by the optical system toward the radiation detector and imaged (see Figure 2a) to individual groups of detector elements 22, 25 and 26, becoming a master 20, first 23 and 2 24 auxiliary points. The auxiliary detectors 25 and 26 can be separately used to make the two-beam push-pull tracking. The first and second detections of the first and second auxiliary detection states can be used by the following equations. Element E, F, G, and Η to illustrate the tracking error signal based on the two-beam central aperture method: 129107.doc •15- 200903473 rE3sPca = (E + F)-(G+H) When the tracking method is used, the tracking error signal RE3sppp = [(A+B)-(C + D)]-Kpp.(EF) + (GH)] can be expressed as follows: where Kpp is in the electronic device. A gain factor that is used to compensate for the difference in radiant intensity between the primary and secondary points on the detector. The overlapping portion of the radiant point 21 and the auxiliary points 23 and 24 will also exhibit optical interference which may cause the RE signal to fluctuate when the interference pattern fluctuates due to, for example, variations in the thickness of the spacer layer between the layers L 丨 and L 。. The unscanned layer will also partially reflect the auxiliary beam focused on the scanned information layer, and 0 will also result in a larger point on the debt detector component of each group that is similar to the light spot 21. However, the strength within such auxiliary beams is usually proportional. The intensity in the main radiation beam is much smaller, so the disturbance due to optical interference is much smaller and does not cause major problems to be solved. The interference pattern is shown in Figure 2b as calculated in a computer simulation. For convenience, the overlapping area between the auxiliary point and the radiation distribution of the zero-order beam reflected by the information layer not scanned is selected as a square. The interference pattern calculated in the auxiliary points is used for the spacer thickness of a 25 〇〇〇 (left) and Α 065 μη (right). The gray area indicates the total surface used for the detector. It can be seen that all edges are white for the 25 〇〇〇 _ spacer and black for the 25.065 μΓ spacer. Therefore, the thickness variation of the door of only 65 nm may have caused a large change in the interference pattern. This is also (4) the feeding signal that is desired to be obtained from the system, such as, for example, three push-pull signals. Measurements have been shown on typical double-layer BD discs, and variations in spacer thickness on the circumference to 129107.doc 200903473 300 nm are common. This means that when scanning such a dual-layer BD disc, a large change in the push-pull signal can be expected. Those skilled in the art will appreciate that this will be similar to scanning an optical scanning device having more than two information layers of an optical record carrier. In conventional optical scanning devices, the diffraction pattern position of the diffraction grating is spatially fixed. In an optical scanning device in accordance with an embodiment of the present invention, the optical path of the target is modulated relative to the optical path of the beam. By moving the 'diffraction pattern f, the phase of the diffracted radiation beam will change, but; affect the phase of the zero-order wheel beam. After reflection by the Μ record carrier, the interference between the auxiliary point and the reflection of the zero-order radiation beam from the defocus information layer (the unscanned layer) will also be modulated by the variable phase. The position of the grating ( (with period a) determines the phase Δφ of the diffraction order m(|m|>0), so when the grating moves 鈥, the phase of the claw is: △+=2mnAx/a grating (ie diffraction) The movement of the pattern can be done mechanically, for example using electromagnetic actuation. °, a pressure actuator (as shown in Figure 3a with respect to 3b) or other suitable mechanical displacement member. The schematic of a specific embodiment in Q 3 a shows a phase modulation member 3〇 having a diffraction grating 31 attached to a pressure actuator 33. The schematic diagram of a particular embodiment in the drawings shows a phase modulation member 30' having an electromagnetic actuator having one or more coil turns that cooperate with one or more magnets 35 for the winding of the grating 31. The displacement of the pattern. The grating system is displaced in the Δχ direction. 129107.doc -17- 200903473 Preferably, the displacement is a periodic displacement because this limits the displacement and size. When the displacement is perpendicular to the optical scanning device, the position of the auxiliary point on the detector is not affected, so the diffraction pattern of the system is preferably in the direction of displacement. Usually three beams of gratings have linear grooves and when the displacement is substantially perpendicular to this groove, the effect of modulation is optimal, and the system is preferentially selected, for example, when the angle is 45 degrees, due to the effective Δχ with angle Xi ^ and minus 'this effect is reduced to about 70%, however, it is still available. Depending on the mechanical requirements of the actuator in the optical scanning device, the most suitable displacement angle can be selected. The frequency of the phase modulation depends on the displacement rate of the diffraction pattern. Preferably, the phase modulation frequency is greater than The servo loop bandwidth has a sufficiently large modulation frequency with a phase of the auxiliary 1 point to average out the interference pattern. The real τ can limit the displacement rate of the diffraction pattern due to, for example, the power limitation in the actuator. The high acceleration of the pattern, the force required (and therefore the power) increases rapidly. Since the servo loop bandwidth of the servo electronics can depend on the system's scan C/14 rate' modulation frequency during the scan may need to be adapted to the system. ^ Servo on-going bandwidth setting 'so that the frequency of the (better) position modulation is greater than the applied setting of the servo loop bandwidth of the servo electronics. The tracking error signal of the auxiliary point does not need to contain the full bandwidth of the servo. Because the change in beam thickness or thickness of the spacer layer is usually relatively low frequency distortion. The main point tracking signal can be used as a high frequency variable. The car is tied, and the phase change of the auxiliary point is faster during the scanning than the beam target and the expected crosstalk. The push-pull signal of the auxiliary point will be enough to compensate the beam target, and the effect of the coherent crosstalk will be averaged. 129l07.doc •18- 200903473 Preferably, a low-pass chopper or band-pass chopper can be used in the feeding circuit electronics of the optical scanning device to eliminate the push of the moving light in the auxiliary point. Modulation of the pull. In another embodiment (shown schematically in Figure 4), in accordance with the invention: the diffractive pattern is by a suitable material 42 (e.g., a photoacoustic modulator 40) having photoacoustic properties. The pressure wave is generated in the middle. The s force wave will cause the diffraction pattern 4 to be generated: the refractive index modulation " the sound wave propagation, the pattern will move (indicated by the direction of the arrow in Figure 4), and this will lead to the auxiliary point Phase modulation. The speed of sound and the frequency of the sound wave determine the period of the pattern. & can be achieved in the acousto-optic modulator, the frequency is usually in the order of 1 () to (10) MHz (depending on the sound and light modulator and materials used) Type) need to get a period p The frequency f of the diffraction pattern is given by f = v / (pn), where the (optical) refractive index η of the material after the speed of sound. The typical value for the material parameter v is about 3 km / Sh about 2, for (four) μ Γ Leads to approximately 30 halls (1). As can be appreciated, this value depends on the material used for the acousto-optic modulator and the desired grating period to obtain the appropriate diffraction angle of the diffracted light beam. In this way, with the servo bandwidth The diffraction pattern is fast enough and the interference pattern will be averaged off (usually on the order of a few 10 kHz). In yet another embodiment of the present month, the diffraction pattern is as shown in Figure 5. A t-modulator 50 having an electro-optic modulation material, such as a night crystal material 52. A diffraction pattern, using, for example, a patterned electrode made of a transparent 1:0 material 51 produced. The phase depth of the pattern can be varied by voltage on the patterned electrode. The diffraction pattern can be reversed by, for example, switching the voltage from V to -V '. In a state (such as having 129107.doc •19·200903473 plus +v) and the other parts of the 'radiation phase 1 ^ h, through the electrodes
’儿咏致别Αφ。在另一 H 經其他部分之_ 4 μ 心（如已施加-V)中，與行 ‘射相比，通過兮·望带& 位滯後。依& μ、、極之輻射具有△(()的相 的方式，較高階繞射階韓射束之相位可且有 π的相位切換。芒士 & 4& t 不< ^目诅』具有一 点 、 、/、伺服頻寬相比係足夠快地完 成’職射_器上之辅助 凡 或者， τ 07卞擾圖案將被平均掉。 或光學遽波器或帶通遽波器用於光學掃描裝置 光_㈣Μ子11件，以消除由於移動 先栅在輔助點之推挽中的調變。 斤有Γ上具體實施例中，輔助韓射束可係第一階繞射 :署 亦可為較高階繞射轄射束。亦可能該光學掃描 計=應用係需要第—及較高階繞射轎射束，用於（例如） 特疋循轨祠服信號目的或光碟格式相容性需要。 ，取決於用於相位調變之裝置類型，可應用一正弦、鑛齒 形、二角形、二元或任何其他適合調變形狀。 雖然本發明係關於—種用於掃描-具有兩個資訊層之光 學記錄載體（例如时或_)的光學掃描裝置詳述，本發明 亦m能掃描多種類型的光學記錄載體（例如用於如 BD々DVE^CD之所有三種類型）之光學掃描裝置，以及具 有夕：兩個資訊層的掃描光學記錄載體來加以應用。 儘g本發明係關於一散光聚焦方法來解釋，但本發明亦 可組合其他聚焦方法（例如點大小债測或刀口方法）來加以 應用。亦可應用一差分散光聚焦方法。 【圖式簡單說明】 129107.doc -20- 200903473 圖i係一光學掃描裝置之佈局的示意圖。 圖2包含圖2a及2b，其具有去捃和夕7 …畀田知描多個資訊 载體時在光學掃描裝置之偵測器 尤子纪錄 益上的干擾圖案之示意圖。 圖3係根據本發明在圖3 a巾夕M ZA < 你回aT之壓致動器及在圖3b中的電 磁致動器之兩具體實施例的示意圖。 圖4係根據本發明使用聲光調變器之另一具體實施例的 不意圖。 圖5係根據本發明使用電光調變器之又另一具體實施例 的示意圖。 【主要元件符號說明】 1 光學掃描裝置 10 輪射源 11 繞射光柵 12 分光器 13 準直儀透鏡 14 物鏡 15 多資訊層記錄載體/光學記錄载體 16 輻射偵測器 17 輻射束 18 輻射 19 輻射束 20 輻射點 21 輻射點 22 偵測器元件 129107.doc 21 200903473 23 第一輔助點 24 第二辅助點 25 輔助偵測器 26 輔助偵測器 30 相位調變構件 30' 相位調變構件 31 繞射光柵 33 壓致動器 34 線圈/電磁致動器 35 磁鐵/電磁致動器 40 光聲調變器/聲光調變器 41 繞射圖案 42 材料 50 電聲調變器/電光調變器 51 圖案化電極（組態） \ 52 液晶材料 L0 資訊層 L1 資訊層 129107.doc -22-‘Children’s 咏 Α Α. In the other H's _ 4 μ heart (if applied -V) in other parts, it is delayed by the 兮·望带 & According to the & μ, the pole radiation has a phase of △ ((), the phase of the higher order diffraction order Han beam can have a phase shift of π. Mans & 4 & t not < ^ 』With a point, /, / servo bandwidth is faster than the completion of the 'professional _ on the device, or τ 07 卞 图案 pattern will be averaged off. Or optical chopper or bandpass chopper for Optical scanning device light _ (four) scorpion 11 pieces, in order to eliminate the modulation due to the movement of the first grid in the push-pull of the auxiliary point. In the specific embodiment, the auxiliary Korean beam can be the first-order diffraction: It can be a higher order diffraction beam. It is also possible that the optical scanner = application system requires a first- and higher-order diffracted beam for (for example) special tracking orbital signal purpose or disc format compatibility. Needed, depending on the type of device used for phase modulation, a sinusoidal, orthorhombic, digonal, binary or any other suitable modulation shape may be applied. Although the invention relates to scanning - having two Optical scanning device for information layer (such as time or _) optical scanning device detailed, this It is also possible to scan optical scanning devices of various types (for example, all three types such as BD々DVE^CD), and scanning optical record carriers having two information layers for application. g The present invention is explained with respect to an astigmatism focusing method, but the present invention can also be applied in combination with other focusing methods (for example, point size debt measurement or knife edge method). A differential dispersion light focusing method can also be applied. 129107.doc -20- 200903473 Figure i is a schematic diagram of the layout of an optical scanning device. Figure 2 includes Figures 2a and 2b, which have a detouring and eve 7 ... Schematic diagram of the interference pattern of the detector. Figure 3 is a two-dimensional pressure actuator according to the present invention in Figure 3a, and the two electromagnetic actuators in Figure 3b. BRIEF DESCRIPTION OF THE DRAWINGS Figure 4 is a schematic illustration of another embodiment of the use of an acousto-optic modulator in accordance with the present invention. Figure 5 is a schematic illustration of yet another embodiment of an electro-optical modulator in accordance with the present invention. the Lord Description of the symbol of the component] 1 Optical scanning device 10 Rolling source 11 Diffraction grating 12 Beam splitter 13 Collimator lens 14 Objective lens 15 Multi-information layer record carrier / optical record carrier 16 Radiation detector 17 Radiation beam 18 Radiation 19 Radiation Beam 20 Radiation point 21 Radiation point 22 Detector element 129107.doc 21 200903473 23 First auxiliary point 24 Second auxiliary point 25 Auxiliary detector 26 Auxiliary detector 30 Phase modulation member 30' Phase modulation member 31 Winding Shot grating 33 Pressure actuator 34 Coil / Electromagnetic actuator 35 Magnet / Electromagnetic actuator 40 Photoacoustic modulator / Acousto-optic modulator 41 Diffraction pattern 42 Material 50 Electroacoustic modulator / Electro-optic modulator 51 Pattern Electrode (Configuration) \ 52 Liquid Crystal Material L0 Information Layer L1 Information Layer 129107.doc -22-