200400500 玖、發明說明： 【發明所屬之技術領域】 本發明係關於具有由覆蓋層突出之突起部之碟狀光記錄 媒體。 【先前技術】 作為碟狀光記錄媒體，已知有圖6所示之構造之cD (Compact Disc:音樂資訊播放專用光碟）。係呈現由透 鏡80所會聚之雷射光81之照射侧依序堆疊厚約i 2 mm之透 明光碟基板82、覆蓋於其上之反射膜83、覆蓋於反射膜83 之保護膜（UV硬化樹脂）84之構造。反射膜83使用具有高反 射率之金屬反射膜，例如鋁膜。 圖7係表示2層構造之DVD (Digital Versatile Disc或 Digital Video Disc ;數位多用途光碟或數位影音光碟）。利 用〇·6 mm之2片基板92a及92b之貼合而構成mm之厚 度。在透鏡90所會聚之雷射光91之照射側設有半透膜（2層 部、L-1層）93a’並隔著中間層94設有反射膜（1層部、L-0 層）93b 〇 在圖8中’參照符號1 〇 1係表示使用薄型覆蓋層之構造之 單層之南被度記錄用之光碟。此光碟1 〇丨係在基板1 〇2之一 主面依次堆疊反射膜或記錄膜1〇3、覆蓋層1〇4所構成。高 數值孔徑（NA)之透鏡1 〇5所會聚之雷射光係照射於反射膜 或記錄膜103。 在圖9中，參照符號丨丨丨係表示使用2層構造之高密度記錄 用光碟之構成。如圖9所示，此高密度光碟丨丨丨係在基板i i 2 上依次堆疊反射膜113、中間層丨丨4、半透膜115及覆蓋層116 82403 200400500 所構成。 【發明内容】 申請專利範圍第1項之發明之碟狀光記錄媒體係包含：基 板、形成於基板上之訊號記錄層、形成於訊號記錄層上之 覆蓋層、及形成於中央部之開口部者；其特徵在於：在大 於開口部周邊之夾片區域之直徑而小於訊號區域之内周側 直徑之第-區$、與大於訊號區域之外周侧直徑而小於光 碟直徑之第二區域之至少—方區域中，基板包含環狀之突 起部，且突起部之前端由覆蓋層突出者。 在本發明中，由於具有前端由覆蓋層突出之突起部，因 此，即使在訊號讀取面朝下而擺放光碟，或有物品置於訊 號讀取面上，也難以損傷到訊號讀取面。又，因在基板上 設有突起部，可將突起部與基板一體成型。又，訊號記錄 層係表示反射膜或記錄膜之意。 【實施方式】 以下，一面參照圖式，一面說明有關本發明之實施形態。 在圖1A及圖1B中，參照符號1係表示本發明之一實施形態 之光碟。此光碟1具有與參照圖8所說明之光碟丨〇丨同樣之構 成即，此光碟1係在基板2之一主面依次堆疊反射膜或記 錄膜3、覆盍層4所構成。基板2例如係由聚碳酸酯（pc)及環 烯垤聚合物等低吸水性樹脂所構成。高數值孔徑（na)之透 1¾ 5所會聚之雷射光係照射於反射膜或記錄膜3。透鏡$例如 具有將2片透鏡貼合之構成，其NA值為〇85。在可錄式光碟 <情形，例如係使用相位變化膜，作為反射膜或記錄膜3。 82403 200400500 在基板2之中心形成中心孔（開口部）6，中心孔6之周邊之 厚度構成比設有覆蓋層4之訊號區域更厚。以一例加以說明 時’光媒直控為120 _，中心孔6之直徑⑺口徑）為15 _。 中^孔6之周邊為夾片區域7，其外周侧設有訊號區域8。 覆1層4係以覆盍訊號區域8之全體之方式被覆設。在夾 片區域7並未設置覆蓋層4，基板2之厚度略厚，呈現與設置 覆蓋層4之區域同等之厚度（1.2 mm)。 内周A起部9a係與基板2成一體地形成於大於中心孔$之 周邊之***區域7之直徑而小於訊號區域8之内周側直徑之 第一區域，外周突起部9b係與基板2成一體地形成於直徑大 於訊號區域8之外周側直徑而小於光碟直徑之第二區域。例 如如圖2所示，將此等突起部9a及9b連續地形成圓周狀。 又’哭起部9a及9b之各其高度ha、hb係以使其前端由覆蓋 層4之面突出之方式加以選定。 在圖1A及圖1B之構成中，基板2雖具有内周突起部9a及 外周突起部9b雙方，但只要設置至少其中一方即可。又， 此等突起部9a、9b也可不連續地形成圓周狀（環狀）而如圖3 所示，採用沿著圓周間歇地（即除去環狀之一部分）形成之 方式。另外，突起部9a及9b之形狀並無前端呈現平面之必 要，也可形成曲面。 内周突起部9a及外周突起部9b係與基板2形成為一體。以 一例加以說明時，利用注塑成型法形成基板2時，在圖4中， 使用參照符號3 0所示之注塑成型裝置。此注塑成型裝置3 〇 具有模具40、注塑部31、料斗32、油壓馬達33、鎖模料筒 82403 200400500 34、噴嘴35等。又，注塑部3丨具有加熱料筒36及螺桿37等。 圖5係表示此設於此注塑成型裝置之模具4〇之一例。此模 具40具有固定側模具部4〇a與可動側模具部4〇b。而，固定 側模具部40 A具有固定侧安裝板4丨、外周環42、固定侧反射 鏡43、固定側調溫電路44及注道45。另一方面，可動側模 具部40B具有可動側安裝板46、可動側反射鏡47、中心銷48 及澆口料切除衝頭49。 其次’說明有關使用上述注塑成型裝置3丨之基板2之製造 工序。首先’將光碟原模2 1裝入固定側模具部40A之特定位 置。又，在此，有一部分省略圖示，即：在將光碟原模2 i 裝入注塑成型裝置之前階段，先衝壓光碟原模之中心部， 以形成開口部。 其次，使固定側模具部40A與可動側模具部40B合在一 起，在使噴嘴3 5觸及模具入口後，將熔解之聚碳酸酯等合 成樹脂材料注塑至模具40内使其硬化。又，在基板2成型 後’形成覆蓋層4。 在上述基板2之成型工序中，在模具4〇之固定側模具部 40 A朝向光碟原模21之面，於對應於内周突起部9a及外周突 起部9b之位置形成環狀之凹溝或突起部。另一方面，也可 對光碟原模21形成環狀之凹溝或突起部。 本發明並不僅限定於上述本發明之實施形態，在不脫離 本發明之要旨之範圍内，可作種種之變形及應用。例如， 也可將内周突起部9a及外周突起部9b形成紗狀。即，在圓 周上連續地或間歇地貼上（植入）富有柔軟性之紗狀（絲狀） 82403 200400500 填充料合成樹脂 受傷，也可擦拭透；大起邵。此時，可防止訊號讀取面 之光碟，也可、^ X ’本發明並不僅限定於單層構造 菜也可適用於圖9所示之2層構造或3層以上之多層光 衝壓法等。…並不限定於注塑成型法’也可使用 部故：所說明’依據本發明，由於在讀取面側設有突起 冑光碟置於桌上時’或將物品放在光碟上時等之 =1防止對讀取面造成損傷。又，將突起部-體形成 於基板時，可簡單地獲得具有突起部之構成。 4 【圖式簡單說明】 圖1A係表示本發明之一實施形態之光碟之剖面圖。 係表示本發明之一實施形態之光碟之剖面圖之局部 放大剖面圖。 圖2係說明本發明之—實施形態之突起部之-例之概岭 線圖。 圖3係說明突起部之另一例之概略線圖。 圖4係具有突起部之基板成型用之注塑成型裝置之剖面 圖。 圖5係注塑成型裝置之模具之剖面圖。 圖6係以往之光碟之一例之剖面圖。 圖7係以往之光碟之另一例之剖面圖。 圖8係表示具有單層構造之高密度記綠用之光碟之剖面 圖。 圖9係表示具有2層構造之高密度記錄用之光碟之剖面 82403 -10· 200400500 圖。 【圖式代表符號說明】 1 光碟 2 基板 3 反射膜或記錄膜 4 覆蓋層 5 透鏡 6 中心孔 7 夾片區域 8 訊號區域 9a 内周突起部 9b 外周突起部 81、91 雷射光 82403200400500 (1) Description of the invention: [Technical field to which the invention belongs] The present invention relates to a disc-shaped optical recording medium having a protruding portion protruding from a cover layer. [Prior Art] As a disc-shaped optical recording medium, cD (Compact Disc: a disc for music information playback) having a structure shown in FIG. 6 is known. A transparent disc substrate 82 with a thickness of approximately 2 mm thick, a reflective film 83 covering it, and a protective film (UV curing resin) covering the reflective film 83 are sequentially stacked on the irradiated side of the laser light 81 collected by the lens 80. Structure of 84. As the reflection film 83, a metal reflection film having a high reflectance, such as an aluminum film, is used. Figure 7 shows a DVD (Digital Versatile Disc or Digital Video Disc; digital versatile disc or digital video disc) with a two-layer structure. The two substrates 92a and 92b of 0.6 mm were bonded together to form a thickness of mm. A semi-transmissive film (two layers, L-1 layer) 93a 'is provided on the irradiation side of the laser light 91 condensed by the lens 90, and a reflective film (one layer, L-0 layer) 93b is provided through the intermediate layer 94 〇 In FIG. 8, the reference numeral 1 indicates a single-layer south-side recording optical disc using a thin cover structure. This optical disc 1 〇 丨 is formed by stacking a reflective film or a recording film 103 and a cover layer 104 in this order on one of the main surfaces of the substrate 1 102. The laser light condensed by the lens 105 with a high numerical aperture (NA) is irradiated on the reflection film or the recording film 103. In FIG. 9, reference numerals 丨 丨 丨 indicate the structure of a high-density recording optical disc using a two-layer structure. As shown in FIG. 9, this high-density optical disc is formed on the substrate i i 2 by sequentially stacking a reflective film 113, an intermediate layer 4, a semi-permeable film 115, and a cover layer 116 82403 200400500. [Summary of the Invention] The disc-shaped optical recording medium of the invention claimed in item 1 of the patent scope includes a substrate, a signal recording layer formed on the substrate, a cover layer formed on the signal recording layer, and an opening portion formed in the central portion. It is characterized in that it is at least-area $ which is larger than the diameter of the clip area around the opening portion and smaller than the inner peripheral side diameter of the signal area, and at least the second area larger than the outer peripheral side diameter of the signal area and smaller than the diameter of the optical disc In the square area, the substrate includes a ring-shaped protrusion, and the front end of the protrusion is protruded by the cover layer. In the present invention, since the front end has a protruding portion protruding from the cover layer, it is difficult to damage the signal reading surface even if an optical disc is placed on the signal reading side or an article is placed on the signal reading surface. . In addition, since the protrusion is provided on the substrate, the protrusion can be integrally formed with the substrate. The signal recording layer means a reflective film or a recording film. [Embodiment] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In Figs. 1A and 1B, reference numeral 1 denotes an optical disc according to an embodiment of the present invention. This optical disc 1 has the same structure as the optical disc 丨 〇 丨 explained with reference to FIG. 8. That is, this optical disc 1 is constituted by sequentially stacking a reflective film or a recording film 3 and a cover layer 4 on one main surface of the substrate 2. The substrate 2 is made of, for example, a low water-absorbent resin such as polycarbonate (pc) and a cycloolefin polymer. The laser light condensed by the high numerical aperture (na) 1¾ 5 is irradiated on the reflective film or the recording film 3. The lens $ has, for example, a structure in which two lenses are bonded to each other, and its NA value is 085. In the case of a recordable optical disc <, for example, a phase change film is used as the reflection film or the recording film 3. 82403 200400500 A center hole (opening) 6 is formed in the center of the substrate 2. The thickness of the periphery of the center hole 6 is thicker than the signal area provided with the cover layer 4. As an example, when the direct control of the optical medium is 120 mm, the diameter of the center hole 6 (diameter (caliber)) is 15 mm. The periphery of the middle hole 6 is a clip region 7, and a signal region 8 is provided on the outer peripheral side thereof. The cover 1 layer 4 is covered in the manner of covering the entire signal area 8. The cover layer 4 is not provided in the clip region 7, and the thickness of the substrate 2 is slightly thicker, showing the same thickness (1.2 mm) as the area where the cover layer 4 is provided. The inner periphery A rising portion 9a is integrally formed with the substrate 2 in a first region having a diameter larger than the diameter of the fan region 7 around the center hole $ and smaller than the inner peripheral side diameter of the signal region 8. The outer peripheral protrusion 9b is integrated with the substrate 2 is integrally formed in a second region having a diameter larger than the diameter of the outer peripheral side of the signal region 8 and smaller than the diameter of the optical disc. For example, as shown in Fig. 2, these protrusions 9a and 9b are continuously formed into a circular shape. The respective heights ha, hb of the crying portions 9a and 9b are selected so that the front ends thereof protrude from the surface of the cover layer 4. In the configuration of Figs. 1A and 1B, although the substrate 2 has both the inner peripheral protruding portion 9a and the outer peripheral protruding portion 9b, at least one of them may be provided. These protrusions 9a and 9b may be discontinuously formed in a circular shape (ring shape), and as shown in FIG. 3, they may be formed intermittently (that is, a portion of the ring shape is removed) along the circumference. In addition, the shape of the protrusions 9a and 9b is not necessarily required to be flat at the front ends, and may be formed into a curved surface. The inner peripheral protruding portion 9 a and the outer peripheral protruding portion 9 b are formed integrally with the substrate 2. For example, when the substrate 2 is formed by the injection molding method, an injection molding apparatus shown by reference numeral 30 is used in FIG. 4. This injection molding apparatus 3 has a mold 40, an injection section 31, a hopper 32, a hydraulic motor 33, a mold clamping cylinder 82403 200400500 34, a nozzle 35, and the like. In addition, the injection section 3 丨 includes a heating cylinder 36, a screw 37, and the like. FIG. 5 shows an example of the mold 40 provided in the injection molding apparatus. This mold 40 includes a fixed-side mold portion 40a and a movable-side mold portion 40b. The fixed-side mold portion 40A includes a fixed-side mounting plate 4 丨, an outer peripheral ring 42, a fixed-side mirror 43, a fixed-side temperature control circuit 44, and a runner 45. On the other hand, the movable-side mold portion 40B includes a movable-side mounting plate 46, a movable-side mirror 47, a center pin 48, and a gate cutting punch 49. Next, the manufacturing process of the substrate 2 using the above-mentioned injection molding apparatus 3 will be described. First, 'the disc master 21 is set in a specific position of the fixed-side mold portion 40A. Here, a part of the illustration is omitted. That is, before the optical disc master 2 i is installed in the injection molding apparatus, the center portion of the optical disc master is punched to form an opening. Next, the fixed-side mold portion 40A and the movable-side mold portion 40B are combined together, and after the nozzle 35 is brought into contact with the mold inlet, a synthetic resin material such as melted polycarbonate is injected into the mold 40 to be hardened. After the substrate 2 is molded, a cover layer 4 is formed. In the above-mentioned forming step of the substrate 2, a ring-shaped groove or a groove is formed on a surface of the fixed-side mold portion 40A of the mold 40 facing the optical disc master 21 at a position corresponding to the inner peripheral protrusion portion 9a and the outer peripheral protrusion portion 9b. Protrusion. Alternatively, a circular groove or projection may be formed in the optical disc master 21. The present invention is not limited to the embodiments of the present invention described above, and various modifications and applications can be made without departing from the gist of the present invention. For example, the inner peripheral protrusion 9a and the outer peripheral protrusion 9b may be formed into a yarn shape. That is, apply (implant) a veil of silk (filament) with a softness on the circumference continuously or intermittently. 82403 200400500 Filler synthetic resin can be wiped through if it is injured; At this time, it is possible to prevent the optical disc on the signal reading side. The invention is not limited to a single-layer structured dish, but can also be applied to a two-layer structure or a multilayer optical stamping method of three or more layers as shown in FIG. 9. . … Is not limited to the injection molding method, and can also be used: the description of 'in accordance with the present invention, since a projection is provided on the reading surface side when the disc is placed on a table' or when an article is placed on the disc, etc. = 1 Prevent damage to the reading surface. When the protrusion-body is formed on the substrate, a structure having the protrusion can be easily obtained. 4 [Brief Description of the Drawings] FIG. 1A is a sectional view showing an optical disc according to an embodiment of the present invention. It is a partially enlarged sectional view showing a sectional view of an optical disc according to an embodiment of the present invention. Fig. 2 is a schematic diagram illustrating an example of a protruding portion of an embodiment of the present invention. FIG. 3 is a schematic diagram illustrating another example of the protruding portion. Fig. 4 is a cross-sectional view of an injection molding apparatus for molding a substrate having a protrusion. Fig. 5 is a sectional view of a mold of an injection molding apparatus. Fig. 6 is a sectional view of an example of a conventional optical disc. Fig. 7 is a sectional view of another example of a conventional optical disc. Fig. 8 is a sectional view showing an optical disc for high-density green recording having a single-layer structure. Fig. 9 is a cross-sectional view of an optical disc for high-density recording having a two-layer structure. [Illustration of Symbols in Drawings] 1 Optical Disc 2 Substrate 3 Reflective or Recording Film 4 Cover Layer 5 Lens 6 Center Hole 7 Clip Area 8 Signal Area 9a Inner peripheral protrusion 9b Outer peripheral protrusion 81, 91 Laser light 82403