Title of Invention

AN OPTICAL DISC WITH A CENTER HOLE

Abstract A disc-shaped optical data recording medium has a signal recording layer for reading and/or writing data using light., and a 10 um t? 200 um thick transparent protective layer disposed over the signal record from layer. The optical data recording medium includes a protrus on projecting from the surface of the transparent protective layer on the light-incidence surface side to which light is emitted to the signal recording layer. The protection is dispersed in an area between a center hole and a damping area where the optical data recording medium is held when reading and/or writing data in the signal recording layer.
Full Text

Optical data recording medium and manufacturing method for the same, and a method for camping the optical data recording medium
BACKGROUND OF THE INVENTION 1. Field of the Invention
The present invention relates to a disc-shaped optical data recording medium having a signal recording layer for recording and/or playing information by emitting a light beam thereto, and a transparent protective layer 10 μm to 200 μm thick disposed over the signal recording layer. The invention also relates to a method for manufacturing this optical data recording medium, and to a method for damping the optical data recording medium. 2 Description of Related Art
Optical discs are known and widely used as a high capacity data storage medium for high density recording and playback of information using a laser beam. These optical discs are broadly categorized as read-only, immediately writable (multisession), and rewritable. Typical of read-only discs are Compact Discs (CDs) storing audio content and Laser Discs storing video content such as movies. Both Incrementally writable (multisession) and rewritable media are widely used in the computer industry, for example, for storing text documents and still image files.
These optical discs typically have a data layer disposed to one main side of s 1.2 mm thick transparent substrate. A protective overcoat is then applied to the data layer, or a protective disc identical to the transparent substrate is

bonded by adhesive to the data layer. See, for example, Japanese Laid-Open Patsnt Publication No, 2001-093193. paragraph [0015] and Fig. 1, and

Japanese Laid-open Patent Publication No. 2002-042376. paragraph [0013]
and Fig. 1
Development and introduction of Digital Versatiie Discs (DVD), a high capacity optical disc medium, has made it practical for even end-users to record moving picture content (such as movies and video) together with audio to an optical disc. High density media such as DVD have been achieved by using a shorter wavelength faser and an objective lens with a large numeric aperture (NA>. However, shortening the beam wavei6)ngt:h and increasing the NA also reduce the tolerance for tilt, the inciination of the disc to the direction of laser beam emission
Tolerance for tilt can be improved by using a thinner substrate. With DVD media this means, for example, using a 0.6 mm thick substrate assuming a 650 nm laser and 0.60 NA. Because a 0.6 mm thick substrate is mechanically weak and would thus increase tilt, DVD discs have two such substrates bonded together with the data recording surfaces en the inside between the substrates.
By using this laminated structure a transparent reflective layer of gold or silicDn, for example, is fomied on the data recording surface of one of the two substrates, and a conventional reflective layer of aluminum, for example, is formed on fhe data recording surface of the other substrate The substrates are then bonded together with these data recording surfaces facing each other on the inside, resulting in a single-sided, double-iayer DVD that can be read from one side of the disc, that is, from the ssde of the substrate having the transparent reflective Tayer over the data recording layer. Rewritable DVD media with a similar double-layer construction are also available, but the data recording surface in this case is a rewritable thin-film recording layer instead of

a meta! mir layer.
Usi a blue-pL-rple laser wiU; an approxirnateiy 400 nm wavelength ha al$)C beeri oposed as a way to achieve even higher rscording densities. Om method u*. ; an approximately 0.1 mn-: thick transparent protective layer on thtde and forms an ultrafine iaser spot using an approximately 0.8! NA ens fvv- signal reading anci'/cr v/riting. The transparent layer can be forme* with the Tj!iowing two methods.
(A; Bonding a transparent substrate slightly less than C.1 mm thick t the signal surface side of a 1.1 mm thick signal substrate using adhesive.
(B) Coating the signal surface side of a 1.1 mm thick signal substrat with an approximately 0.1 mm thick transparent resin layer
In method (A) a polycarbonate sheet manufactured by castiny, fo exaTfiple, is used as the transpareni substrate. Thickness variation in such cas sheats is minima! at approximately +/- 1 pm. The thickness of the adhesive used to bond this polycarbonate sheet to the signal substrate is also thin an( can be easily formed to a uniform thickness. As a result, a transparen protective layer v/ith uniform thickness can be formed on the recording/playbad sid€! of the disc.
With method (B) it is difficult to form a unrformly thick coating because o the thiclTtess of the transparent resin, but a low cost, high density optical disv can be achieved because it is not necessary to use sheets manufactured in t high cost casting process. SUryiMARY OF THE INVENTION
A problem with high density optical discs is that the surface of th€ trarsparen: protective layer Is easily scratched, and scratches can easily caust

a loss of servo control Increasing the mechanical strength of the transparent prolective layer ils6:f increases the fi!m thickness, and is not suited for high density recording, it is therefore difficult lo piotect the surface from scratching whiie keeping the transparent protective layer thin,
TYie data transfer rate during recording and playback Is higher with high density optical discs than conventional CD and DVD media, and the disc therefore spins faster Imbalances in the shape and weight of the disc relative to the spindle hole can therefore increase the load on the rotating spindle (motor).
In addition, high speed rotation of these high density optical discs also^
requires higher disc clamping force than CD and DVD discs '
The present invention is therefore directed to solving these three problems, and an object of the invention is to provide an optica! data recording m€(Jium having surface protrusions for protecting the transparent protective layEsr anc reducing the load on the motor duritig disc rotation, and enabling higher disc clamping force to be applied to the opticai data recording medium.
To achieve the above objects an optica! data recording medium with a signal recording layer for reading and/cr writing data using iight. and a 10 pm to 20C [im thick transparent protective layer disposed over the signal recording !ay€>r. conrprises a protrusion projecting from t^e surface of the transparent projective layer on the light-incidence surface side to which light is emitted to the signs! recording layer in an area between a center hole and a clamping area where the opticai data recording medium is held when reading and/or writing
data in the signal recording layer.
' " "'.■"■-■ ■ .
Because this protrusion is on the inside circumference side of the

clamping area, the protrusion wilt not interfere (collide) with the optical head Furtiarmcrs, when the optical data recording rriedium is placed on a flat surface with the trensparent protective layer side fcic'ng the fiat surface, the protrusion keeps the t^aniiparent protective layer off the flat surface and thereby prevents scratching the transparent protective layer.
The load imposed on the rotating spindle (motor) caused by a weight imbalance in the protrusion is also reduced t)ecause the protrusion is located nea' the center spindle hole.
The protrusion is preferably disposed separated at least 0.1 mm iri the radial direction from an outside edge of the center hole. This configuration prevents the protrusion from interfering with the center cone used to hold the opti::al data recording medium at the spindle hole in the disc recording and pia>back drive, and thereby enables stable clamping of the optical data reccjrdifK] medium.
In another aspect of the invention a disc-shaped optical data recording
»
medium with a signal recording layer for reading and/or writing data using light, and a 10 pm to 200 pm thick transparent protective layer disposed over the signal recording layer, is characterized by having a damping area on the oulKJde o*' the center hole in the radial direction for holding the optica! data rec
information.
When this opticai data recording medium is plsced on flat surface with the transparent protective layer thereof facing the flat surface, the proximity of the protrusion to the signal area keeps the transparent protective layer separated from the flat surface and thereby provides excellerV, protection for the transparenl protective layer.
Preferably, the protrusion is disposed to an area within 2 mm to the OLitsjjde in the radia! direction from the ou-^side circumference edge of the clanping area.
Interference between the protrusion and the opticai head is thus further prevented because the protrusion is sufficiently separated from the signa! area."
A disc-shaped optica! data recording medium tiaving s signal recording lay€»r for reading and/cr writing data using light, and a 10 pm to 200 pm thick transparent protective layer disposed over the signal recording layer, according to c further aspect of the invention is characterized by a clamping area on the outside of the center hole in the radial direction for holding the optical data rea)fding medium when reading or i ©cording the signal recording layer; a signal area on the outside of the clamping area in the radial direction for recording or reading data in the signa! recording layer; and a protrusion projecting from the sunace of the transparent protective layer in the clamping area on the light-incidence side of the signal recording layer to which hght is emitted for reading ana/or waiting information.
This optical data recording medium is clamped on both sides of the pro'jusion in the damping area There is therefore no interference (coilision) with the opticai head, and the transparent protective layer will not be scratched

when th8 cisc is placed on a flat surface with the transparent projective layer facing said flat surface because the protrusior diiiposed to the same side of the disc keeps the transparent protective layer rais>ed above the flat surface.
Further, greater clamping force can be applied and the disc can be spun statiiy. assuring good signal quality. The load imposed on the rotatir^g spindle (motor) caused by a weight imbalance in the protrusion is also reduced because the protrusion is located near the center spindte hole.
Preferably, the protrusion projects to a height of 0.05 m?-n to 0.5 mm from ; the surface of the transparent protective layer. The transparent protective layer will therefore not be scratched when the disc is placed on a flat surface with the transparent protective layer facing the flat surface because the protrusion projects sufficiently above the disc surface on the same side to keep the transparent protective layer from contacting the flat surface. Scratch-prevention and cost are further improved if the protrusion height is further preferably 0.1 mm to 0.3 mm from the surface of the transparent protective layer.
Yel further pieferabiy. the wavelength of light for recording or reading Information in the signal recording layer is 410 nm or less so ttiat a small beam spot enabling high density recording and playback can be acfiieved.
Another aspect of the present invention is a manufacturing method for a disc;-shaped optica! data recording medium having a signal recording layer for reading and/or writing data using light, a 10 [jm tc 200 pm thick transparent projective layer disposed over the signal recording layer, and a protrusion projecting from the surface of the transparent protective layer on tlie light-incidence surface side to which light is emitted to the signal recording layeir. Thii> manufacturing method has steps for; preparing a first die with a cavity

the transparent protective taye- on the light-incidence surface side to which lig is eiTiitted to the signal recording layer, the p'otrijsion is formed on the optic date! recording medium by bonding thereto a psrt in the shape of the protrusior
By thus bonding parts forming the desired shape of the protrusion to W disc surface, this optical data recording medium manufacturing method c In ar>other aspect of a manufacturing method for a dssc-shaped optic date! recording medium having a signal recording layer for reading and/or wrlti! dat£j using light, a 10 pm to 200 pm thick transparent protective layer disposi ove' the signal recording layer, and a protrusion projecting from the surface the transparent protective layer on the light-incidence surface side to which lie is emitted to the signal recording layer, the protrusion is formed on the opti{ data recording medium by dripping a liquid material onto the optical de recording medium and curing the liquid material in the shape of the protrusion
This manufacturing method can easily produce protrusions of the desir shape ai tne desired location of the disc surface by simply changing fjow t liquid material is dripped onto the substrate. Little time is also needed to foi the protrusions, and optica! data recording media having protrusions accordi to the present invention ran therefore be manufactured at low cost
in another aspect of a manufacturing method for a disc-shaped opti^ data recording medium having a signal recording layer for reading and/or v^riti data using light, a 10 pm to 200 pm thick transparent protective layer discos over the s":gnal recording layer, and a protrusion projecting from the surface the transparent protective layer on the light-incidence surface side to which !i^

correspona-ing to the protrusion, and a second d.e corresponding to the first die; disposing :3nd closing the first die and second die togeiher; injecting resin, betv/een the nrst die and sea^nd die; curing the cesin to form a resin molding havng the proirusion; and opening the first dif^ and second die, and removing the cured resin molding.
In another jranufacttring method for a disc-shaped optical data recording medium having a signal recording layer for reading and/or v/riting data usir;g light, a 10 pm to 200 [.in thick transparent protectiv.^ layer disposed ever the signal recording iayer, and a protrusion projecting from the surface of the transparent protective layer on the light-incidence surface side to which light is emitted to the signal recording layer, a substrate for the optica! data recording medium is formed by injection molding using Q die having a cavity corresponding to the protrusion, and the protrjsicn is sirntJilanecusly formed on the substrate.
These mancffactunng methods for an opt:cal data recording medium according :c the present invention provide a cavity corresponding to the desired snape of tne protrusion in a die, and then introduce molten resin to the mold anc appii' pressure in an injection rrjolding process. This produces a substrate with a sicral pattern transferred from the stamper in the mold and a protrusion simtultanecusly formed to the substrate surface, thereby improving mass production of t^le optical data recording medium.
In another aspect of a manufacturing method for a disc-shaped optical data recording medium having a signal recording layer for reading and/or v/riting data using light, a 10 pm to 200 pm thick transparent protective layer disposed over the signal recording layer, and a protrusion projecting from the surface of

is fi'nittevl to the signa! reccrding layer, the protrusion is forrned on the optica^ datci recording niedl jrn by a scr*aen printing process usino a screen having the des red shape of the protrusion.
This manufacturing msSthod can easily produce protrusions af the deslrec sha;:?e at the de.^ired location cf. {he disc surface by simply changing the pattern of tiie protrusions in the screen Littie tirn^ is th^erefore needed io form the protrusicns. and opfical data recording media having protrusions according to the :)resent iriventjcn can ther^ifore be manutcjctu^ed at low cost.
The material used to maka the parts bonded to the optica! data recording medium su'face, and the material of the protoisions formed by screen printing, in the optical data recording medium manufacturing methods described above is pf'efersby a resirv This makes materials handing simple, enables usincj low co^;.t materif^ls, and improved productivity. The rasin is further preferably a UV-ci:rt' resio, a thermosetting r€?sin. or a pressure-sensitive adhes've Each of these mate-jais is inexpensive and easily procured.
Fijm&r preferably, the protrusion is oisposed in an area between the cemer ho^e and a clamping area where the optical data recordirig mediiim is heic for reading and/or v^^iting data in the signal recording layer
This configuration locates the protrusion on the optical data recording rnecium surface on the inside circumference side of the clamping area. The proi'-usion therefore dees not interfere (collide) with the optical head, and the transparent protective layer vvill not be scratcnec when the disc is placed on a flat :>urfac:e with the transparent protective layer facing said flat surface because the protrusion disposed to the same side of the disc prevents the transparent protectlvtj iaysr from touching the flat surface. Disc reiiability can therefore be

assured for a long time.
Yet further prefsrably, ti?e protrusion is disposed in an area fcelweon the cia^-tptng area for hoi»:iing the optical data n>.:on.itr;g mod-iun- when reading or recc.Tdinc data in the signa! recording layer, and the signal area for r&cording or rea Ye? further preferably, the protrusion is disposed to an area vWthin 2 mm to the oi!tside in the radia! direction frooi the outside circumference edge of the danping area. In this c^se the optical dnta recording medium assures no inte1erenc(? between the protrusion and opitcai head regardless of the recording and playback device in which it is Lsed.
Yet further preferably, tne protrusion is disposed in the ciamping area for hoiding Ih-e optica! data recording r^edium 'Ahen reading or recording data in the signal receding layer.
Beca-jse the disc in thiB case is damped on bcih sides of the protrusion, the protrusion is prevented from interfering with the optical head while also proecting the transparent protective layer. Greater damping force can also be applied to !he optical data recording medium
Yet further preferabiy. the protrusion is fofrrjed to a height of 0.05 mm to 0.5 mm from the surface of the transparent protective layer Because the pro.rusion thus projects sufficiently from the transparent protecrive layer sutface With thiis configuration, the transparent projective layer will not be scratched whon the disc is placed on c^ flat surface because the transparent protective layer is prevented from touching said flat surface by the protrusion. A more dependable optical data recording medium can therefore be manufactured.
Scratch-prevention and cost are further improved if the protrusion height

Is fiirfne." p;referably 0.1 mm to 0.3 mm fron the surface of [he transparen; protectivo leyer
Another '-jii^p^ci of the preseot iriventiur; \^ a ciainpir^y p.ieiiKK'J for a disc-shaped cptical data recording medium having a sigrtai recording layer for refjding and/or writing data by emitting light using an optical head with a 0 7 to OS numeric aperture, and a 10 fjm to 200 jjm thick transpareni protective layer disposed ever the signal recording layer. The optical data recording medium has a clamping area on the outside of the center hole in tiie '•adial direction for holding the optical data recording medium when reading or recording data in the sigra! recording layer, a signal area on the outside of the damping area in the radial direc'non for recording o' reading datci in the signal recording layer, and a prctrusior projecting from the surface of th::? trarsparen* proii^ctive iayer in the clanping arB3 on the iigt^t-incdence side cf the signal recording layer to v^^hich !igh: is omitted for reading and/or vvnting infor'yiatioM. The damping method holds the optica! data f^ecording medium on both sides o*^ the protrusion when recordif'is or reading data in the signal rer:.arding layer of the optical data recording medium
By noiding the optical data recording medium on both sides of the prcirusion, this disc clamping mathod c-an appiy greater damping force, the disc can be spu"* stably, and good signal quality ca.n be achieved
Preferably, the area for clamping on both sides of the protrusion on the iigh: incidence side is in a radial area with a radius of 11 mm to 16.5 mm.
Yet further preferably, :he optical data recording medium :s clamped by boH; holding the optica! data recording medium on both sides of the protrusion on the light incidence side and holding the protrusion.

By thus clamping the disc in TNA^O c-treas on opposite sides of the p^'OirusiOfi ar.d by applying pressure directtv to fhe prctrusion, ever^ (jreater clamping fcr<:e can be applied.> With an optica! data recording mediuTi ^^cccrding [c She pr^rsent invention the pfotfU';>ion will not interfere (ccliide) .vith the optica! head and the transparer!■ protective layer is prot'^cted froir scratches wlien the disc is placed transparent protective layer-side down on a fiat surface because the prctiusior^, pre\'ents the transparent protective layer froT. touching the f!a1 surface
Kcrthermore the load en the rotating spindle (motor) caused by a weight imbalance in the protrusion is also reduced barause the protrusion iS located nea- the cenfej* spindle hole
The damping method of an opiical daia recording mediuin 3ccO''d!ng to the present invention holds the optica" data recording mediuni in a cla^iping area on either or both sides of the protrusion. The optical data recordirig medium can therefore be held and spun stabiy dunng recofding and playback, ass jring consistant recording and playback and good signal quality.
Tne optical data recording rr-edium manufacturing metriod of this inv€:ntion can also easily form the protrusion thus improving optica! data recordino medium productivity.
Otiier oojects The preserit invention will become readliy understood from the following descriptior"^ of preferi'ed embodiments tharaof mace vt'ith reference to the

ru.;n err?l, and in vvhich:
is a plan w^ew vof the same aisc;
Fiy. 2A -o Fici 2E are paniai seci'un vi.v,viv of possible pro-'Lsior^ c^h^pos,
rig. 3A to Fh;; 3C ^hcw vaficuc' co'^^lgL-raLicn^ of ire prciri'Slon ^\he\\ see 1 if"^ plan view frorr; a!::iOve the protrusion
FiQ. 4 is a section view of ancthe; optical aaia recordirig :nediu:T ir: vvfi-ch the configuralion OT the araa ^on the ;>pir:c!'8 hai«3 lO ihe darnpinu ar^a oiffers ffoni tha- snov/n in Fig 1:
FiC. 5A ^0 F'o. 5C ore s-f-ction v:ev.'^ .>f 3 '^I'S' r^eii^od o^ iri3r.L;fa:::t-n'v:! a;~
inve-ntior:
FQ, 6 shc'rvs a second meti'^oc C rrianufac-K-ir.ng an c■DtK:^^' n^f^^ recording medium having a prot:iis:on 3ccG:ding o tns pr-^sent ir^ven-inrv
F;c. ?A cirid "ic^, 7B shew a third nr^sthod of nianufdcii'i u.c ^n optica: d:^:di t*ea;rdsng nied-u^n having a protrusion according '.o the p'^^.sent ;'• venricr;:
F't^. 8A i-^ c. pariif^i serton ^/ii:::vV o*" c^in opiica! date r^roj'cimg ireo!Li:r navipq a p'otriislon accc"\:iina to a second ernocnsr^e'^ of th3 oresert ;nvf^■^t^:;n anc Fig. SB iS a partial plan vitnv of ^he sarre optical disc,
Fics 9 i£^ a Portia! section v;ow ^i'^owing reading anri/or A^-niPc dat:^i :o che data r^:ccr'Jinc; iaver of an optica; data rccofding mediur- having 3 protr'^sion according ic a second embodiment of the invention;
Fie. 10 "ihcvvs an example of a rr^e^hod o^ fonriirg ti>? protrusion in a

netiod i":,T n'tanofciCiLvri-'^c a;: oDncai date ^^K-/idifiQ ;^}edK-.rr; acco^ciinc to the second ^:~ibod front j^:hc invenuon;
Ihi^cl embodiment cf the invention;
Fig. ^2A io F\q, 1 2C 3(f- partial ^'-^cNjf. Jew-:; o!' whuckiprj i^;t- opiicai 'Ja^H: recordlno r^ediuin ?cr readinq ando' writi^ig dc4a :o the data recording Icy-^r
Fin 13 is a parriai seciion vic^v./ showirv^ a w^ped opiicai d^ta recofd:r>9 medium placed on a fiat .surtace;
F-[]. 14A aiid Fig l-'^-c] shjv/ oxan'^nies of an optical C'ciui receding niociium n;^vjna 3. o-.frcs^jiice '.n tno surface elevation of th^: t;ar^srjrsnt proiectivo layer and :ha ciamp-ng area CA:
Flu. '-5 is J p3r;^( ?^3cticr v-^w :it^.;vVi;^q jn c^jiica' dato :'::::::d:ng nnyciiuni lia^Mpg a sr-ailer protfoSiori, af"!d
F.c. 15 :s s par::a! iec:;on view srcv/irc the optica! data re-^ordinc maciiuin of tf-^e li'tiro arr^tocrr-.^.n: >^'hen :!an*.f/ad f-on- both *:op 30c botte:-n tiioes or the dibc DESCRIPTION OF ^HE PREFERRED EMt^ODiMENTS
proter^od embcdinents o!" tpe present tpvenllon ari de^scribed bdovj Mih reicrence tc the acconpany;nc; *!gures Enr!i:'Cdirrient 1
r:o. 1 is a s.d9 section view of a ;>re*errdinc; nieri^um : "0 (also referred to ceiO'A as sinipiy "disc") shown in Fig. 1 ha3 a p'oiruscn "GO disposeri on -xie Su.rfac.e thereof belv/e-en the ins-ce

t^ole 'OV Fig 1A '.s a s^jctiof view of th:?;- o;:*ica! d^ta rr^noid-ry -n'^dii.n^: 1^0 and rig. 1& i^ a top pi^vi vi^v> oltp-^ optica! data rocord-rig 'Tiediur:^ ' 1C
Tfe ouiiid.} ciiciine-er" of 'nis op^icai d?i;ta reoordincj ra^c]\K^::\ VlO is 120 mm Trie cUiinpircj area CA .G the area v-'h-^'-cr the opttci^ii data re^.ordinQ Tseciiurri 1 iO lo c:aripf;d and PeJd when readipq and/or rViiiina datg lo tht sicri;^:! ^sci.ji'dH'iQ layer 103 The risjdG; c-iarr-eter D.:A. of' the c;ampir A t-*^'":sparent protective layer 102 prntacrs the ssgr^al ^ecoraiog layer lOO. A \'xjh\ beav \v\th a 405 nw '-vavetergth. for exaniple i? emitteci frcm ar^ opfca' hcaj 'hro'^gh :he tr-jnr>pi3iont proteorive layer 'Dl-: -jno fccu-Sx^d en the signal recordinc !;;)yer 103 tor reading and/or Vvriting dau:
T^-:^ iranopai^^nt p^cieaiv^; '^ye: 102 :s. for ex^i-oi?. "JCO p-:'i >'n^zK The s.9r:ai re'.;Oi dine 'ayci-- 'OC s? forfned c\er liigrci! pi:c> or groove-^ thn!: a^e fo^T^efj \r t!)e sicp'ji area SA of th Th*^ dian-ieier Dn of the sptrid-s hole 1C1 :3 15 rn^r Tha 'nstde disrTorfir D;; of the p'-OTfusiop irjo ;s 13 in-n, ine ^vidth i'^ tric^ radia! diract'on (radiaJ vv^iclh; is 1 rr\rr.. -'iwi ihe htiiaht of the Drorrus^on i30 ariove the jLJrface cf (r^nsi^^arenl proieui^^e ayer 1C2 iS C.3 nrv:. The r^dia; width cf the pr;:;truSion '^OO .s preie^abh 0 2 vn io I nvn. A v-idth of 0 2 ru\r or greater's prsfenea tc aosu^e r^ufficieni niechanical strength.
Ti'o hi^ight of the protajsicn 100 frorr) the oLoTace of tran':->:aren:
































raspectively.
Unlike in the first and r»6cond embodiments, the disc drive clampi the optical data recording medium 1110 on both sides of the protrusion 1100 in this third embodiment. This is possible except v/nen DCM = Dn or Dto = DCAO Fig. 11B and Fig. 11C show two different ways of damping the optica! data recording medium 1110 on both sides of the protrusion 1100.
In the example shown in Fig. 11B, the ciarnp 1120 applies pressure to the disc in the clamping area on both sides of the protrusion 1100. Tlie disc can be held with sufficient force in this case despite tt^e prclrusicn 1100 becjause the clamping member has a channel providing clearance for the protnjsion 1100^-^^"'^^-"-/:; V ■-■';'-^-^ ;J-"'-^:^
In ihe exampie shown m Fig. VIC, the clamp 1130 applies pressure to the disc ;n the clamping area on both sides of the protrusion 1100. and also app'ies pressure to the protrjsion 1100. This method provides even more positive clamping of the disc because pressure is applied to a larger area of the disc than with the method shown in Fig. 11B.
The optical data recording medium can be held stable and rotated with suff.cient pressure during both recordmg and playback to assure good signal qua ity and reliable recording and playback performance.
It snould be noted that the disc is damped on both sides of the pi ctrusion 1103 in this embodiment, but it could be held only in the area between inside diameter DCAI and the inside circumference edge of the protrusion 1100, or the area between outside diameter DCAC and the outside circumference edge of the protrusion 1100
While thus third embodiment has been described with reference to the
V ; " ' - . ■ ■ " -■
■■',)■

conligurattcm shown in Fig. 11 Jt could be configured as si-^own in Fig 4 and Fig. 8. Fnat is, tl^is proi^rusion could be used on a disc in which the transparent protactivo hsyer is not formed in the clamping area CA. or on a disc in which the transparent protective iayer is not in the clafviping area CA and there is a step betv/een the surface elevations of the signal substrate and the transparent protective layer.
The protrusion 1100 of this third embodiment can also be formed using the same materials and methods described in the first and second erntiodirnents above
The shape and configuration of the protrusion could also be as described In the first embodiment.
Clamping an optical data recording medium according to tne present invention shall not be limited to holding the disc with chucking jaws in the danping area CA on only one s de of the disc as shovw in Fig. 12A to Fig. 12C and Fig. 15. More specifically, the optica! data recording medium could be clamped from both sides of the disc. This is shown in Fig. 16. a section view of the optical data recording medium 1600 being clamped in the clamping area CA from above ai^d below the disc, by means of a top damp 1605 and a bottom
damp 1606, In this example the protrusion 1601 is disposed in the clamping
«
area CA, and the area on both sides of t'*ie protrusion 1601 is supported by bottom clamp "^eoe on the laser-incidence side of the disc.
The materia! used to manufacture the signal substrate is not particularly discussed in the above-described embodiments, but is preferabSy a plastic such as polycarbonate, norbornene resin, or polyolefin resin.
The L'-ansparent protective layer can also be formed by applying a sheet

film thinner than the desired thickness with adhesive, or applying a coat of liquid resin. When a thin sheet film is applied with adhesive, the adhesive could be a UV-oure rosin, thermosetting resin, or pressure sensitive adhesive, for example.
When a coat of liquid resin Is applied, the resin could be a UV-cure resin or themriosetting resin, for example.
Although {he present, invention has been described in connection with the preferred embodiments thereof with reference to the accompanying drawings, it is to be noted that various changes and modifications will be apparent to those skilled in the art. Such changes and modifications are to be understood as included within the scope of the present invention as defined by the abounded : claims, unless they depart there from.






1. A disc-shaped optical data recording medium having a signal recording
layer for reading and/or writing data using light and a 10 um. to 20 um thick
transparent protective layer disposed over the signal recording layer, the optical
data recording medium comprising.
a protrusion projecting from the surface of the transparent protective layer on the light-incidence surface side to which light is emitted to the signal according layer, the protrusion disposed in an area between a center hole and a clamping area where the optical data recording medium is held when reading and/or writing data in the signal recording layer.
2. An optical data recording medium according to claim 1, wherein the protrusion is disposed separated at least 0.1 mm in the radial direction from an outside edge of the center hole.
3. A disc-shaped optical data recording medium having a signal recording layer for reading and/or writing data using light. and a 10 pm to 200 pm thick transparent protective layer disposed over the signal recording layer, the optical data recording medium comprising:
a clamping area on the outside of the center hole in the radial direction for holding the optical data recording medium when reading or recording data in the signal recording layer;
a signal area on the outside of the clamping area in the radial direction for recording or reading data in the signal recording layer; and
a protrusion projecting from the surface of the transparent protective layer, the protrusion disposed in an area between the damping area and signal area on the light-incidence side of the signal recording layer to which light is

emitted for reading and/or writing information.
4. An optical data recording medium according to claim 3, wherein the protrusion is disposed to an a!*ea within 2 mm to the outside in the radial direction from the outside circumference edge of the damping area.
5. A disc-shaped optical data recording medium having a signal recording-layer for reading and/or writing data using light, and a 10 pm to 200 μm thick transparent protective layer disposed over the signal recording layer, the optical data recording medium comprising:
a clamping area on the outside of the center hole in the radial direction for Holding the optical data recording medium when reading or recording the signal recording layer;
a signal area on the outside of the damping area in the radial direction for recording or reading data in the signal recording layer; and
a protrusion projecting from the surface of the transparent protective layer, the protrusion disposed in the clamping area on the !ight4nddence side of the signal recording layer to which light is emitted for reading and/or writing infoTfiation.
6. An optical data recording medium according to claim 1, v^herein
Information is recorded to and read from the signal recording layer using an
optical head with a 0.7 to 0.9 numeric aperture; and
the protmsion projects to a height of 0.05 mm to 0.5 mm from the surface of the transparent protective layer.
7. An optical data recording medium according to claim 6. wherein the
protrusion projects to a height of 0.1 mm to 0.3 mm from the surface of the
transparent protective layer

8 An optical data according medium according to claim 1, wherein the diameter of the center hole is approximately 15 mm;
the protrusion is disposed to an area between a 17.5 mm inside diameter and 22.0 μm outside diameter; and
the height of the protrusion above the transparent protective layer surface is 0.3 mm or less.
S. Ari optica! data recording medium according to claim 8, wherein the : height of the protrusion referenced to the surface of the clamping area for holding the optical data recording medium when reading or recording data in the signal recording layer is 0.325 mm or less
10. An optical data recording medium according to claim 8, wherein the height of the protrusion referenced to the surface of the clamping area for holding the optical data recording medium when reading or recording data in the signal receding layer is 0.275 mm or less
11. An optical data recording medium according to claim 3. wherein the height of the protrusion referenced to the surface of the damping area for holding the optical data recording medium when reading or recording data in the signal recording layer is 0.20 mm or less.
12 An optical data recording medium according to claim 11, wherein the prolrusioi is disposed to an area between a 17 5 mm inside diameter and 21.0 mm outside diameter.
13. An optical data recording medium according to claim 1,. wherein the wavelength of light for recording and/or reading Information in the signal recording layer is 410 nm or less.
14. A manufacturing method for a disc-shaped optical data recording

medium having a signal recording layer for reading and/or writing data using
light, a 10 μm to 200 μm thick transparent protective layer disposed over the
signal recording layer, and a protrusion projecting from the surface of the
transparent protective layer on the light-incidence surface side to which light is
emi:ted to the signal recording layer, comprising steps for:
preparing a first die with a cavity corresponding to the protrusion, and a second die corresponding to the first die;
disposing and closing the first die and second die together;
injecting resin between the first die and second die;
curing the resin to form a resin molding having the protrusion; and
opening the first die and second die, and removing the cured resin molding.
15. A manufacturing method for an optical data recording medium according to claim 14. wherein the first die further comprises a channel corresponding to a signal recording groove for forming the signal recording layer, whereby the signal reco^-ding groove is formed on the resin molding according to the channel after the step of curing.
16. A manufacturing method for a disc-shaped optical data recording medium having a signal recording layer for reading and/or writing data using light, a 10 μm to 200 μm thick transparent protective layer disposed over the signal recording layer, and a protrusion projecting from the surface of the transparent protective layer on the light-incidence surface side to which Sight is emitted to the signal recording layer, wherein:
a substrate for the optical data recording medium is formed by injection molding using a die having s cavity corresponding to the protrusion, and the

protrusion is simultaneously formed on the substrate.
17. A manufacturing method for a disc-shaped optical data recording
meciufVi h£vJr)C) 3 signal recording layer for reading and.'or v^yrit.ing data visinct
light, a 10 urn to 200 μm thick transparent protective layer disposed over the
signal recording layer and the protrusion projecting ftom the ^urtace of the
transparent protective layer on the light-incidence surface side to which light is
emnted to the signal recording layer, wherein:
the protrusion is formed on the optical data recording medium by bonding thereto a part in the shape of the protrusion.
18. A manufacturing method for a disc-shaped optical data recording
medium having a signal recording layer for reading and/or writing data using
light a iO pm to 200 pm thick tran5>parent protective layer disposed over the
signal recording layer, and a protrusion projecting from the surface of the
transparent protective layer on the light-incidence surface side to which light is
emiled to the signal recording layer, wherein:
the protrusion is formed on the optical data recording medium by dripping a liquid material onio the optical data recording medium and cviring the liquid material in the shape of the protnjsion.
19. A manufacturing method for a disc-shaped optical data recording
medium having a signal recording Sayer for reading and/o; writing data using
light, a VJ pm to 20C pm thick transparent protective layer disposed over the
signal reoordir^g layer, and a protrusion projecting from the surface of the
trarsparent protective layer on r.he lighi-.ncidenes surface side to which light is
emitted to :he signal recording layer, wherein:
th.2 protrusion is formtad on the optic^al data recording medium by a

screen piinting process using a screen having the desired shape of \he
prot'usion.
20 A rnanufacturing method for an optica! data reccrdiric niediurr; acccrdiny
to claim 16 wherein the protnjsion is made from a resin material
21. A manufacturing method for an optica! data recording medium according to claim 20, wherein the resin includes at least one of a UV-cure resin, a themosetting resin, and a pressure-sensitive adhesive,
22. A manufacturing method for an optical data recording medium according to caim 16, wherein the protrusion is disposed in an area between the center hole and a damping area whore the optical data recording medium is held for reading and/or writing data in the signal recording layer.
23. A :n':^nufactur:ng method for an optical data recording meQ»um according to claim 13, wherein the protrusion is disposed in an area betv/een the damping area for holding the optical data recording medium when reading or recording datci in the signal recording layer, and the signa^ area for recording or reading datfi in the signal recording layer.
24. A manufacturing method for an optica! data recording medium according to caim 23, vvtierein the protrusion is disposed lo an area within 2 mm to the outside in the radial direction from the outside circumference edge of the clamping area.
25. A manufacturing rnethod for an optical daia recording mediunj according to c aim "6 wherein the protrusion is disposed in the claniping area for holding the optica! data recording medium when reading or recording data in the signal recording layer.
25 A manu-acturing method for an optical data recording medium according

ic caim 16, wherein the protrusion JS tarmed 'o a height of 0.05 mm to 0.5 mm
tfOfT! the surface of me transparent protective layer.
27. A rn;inui'3cturin9 nielhod for an optical data recording mediurr^ according
to claim 16, whtorsin the protrusion is formed to a height of 0.1 nnm to 0.3 mm
froni the surface of the transparent protective layer.
23. A manufacturing method for an optica! data fecording medium according
to calm ^6, wherein the diameter of the center hole is appro.ximateiy 16 mm;
ihe protrusion is disposed to an area between a 17.5 mm inside diameter and 22.0 mm outside diameter; and
the height of the protrusion above the transparent protective layer surface is 0.3 mm or less
29. A rnanufacrtiring method for an optical data recording medium according to claim 26, wherein the height of the prolrusiori referenced sc the surface of the clamping e^rea for nolding the optica! data recording medium when reading or rec 30. A manufacturing method for an optica! data recording medium according to claim 28, wherein the height of the protrusion referenced to the surface of the clamping area for holding the opticai data recording medium v/hen reading or recording data in the signal recording layer ts 0.275 mm or less.
31. A rYianufactuf ing method for an opticai dai;a recfjrUing medium according to claim 28, wherein the height of the protrusion referenced to the surface of the clamping area for holding the optica! data recording m.edium Vv4ien reading or recording data in the signal recording layer is 0.20 mm or less.
32. A manufacturing method for an optical data recording medium
according :o claim 31, wherein the protrusion is disposed to an area betv^/een a

17.f) mm inside diameier and 2A.Q mm outside diameter
33. A rnfanufacturng mechoj :of an optica! data recorJing msd'un' according
to GiaiT. "3., v/h-srein the protrus'on is cr\ad-j irorn a resin matenai
3^ A fn;.inu'actLir;ng method for an optical data recording medium- according
to daim 33. wherein the resin iricludes at iea;=it one of a UV-':ure resin, a
thefmosetting resin, and a pressure-sensilive adhesive.
35. A nii^inufacturing method for an optica! data recording medium according
to claim Ifi. wherein the protrusion is disposed in an aren belween the center
nolo and a ctamping area where the optical data recordinQ rriedium is hela for
reading and/or writing data in the signal recording layer.
36 A manufacturing method for an optica! data recording medium siccording
to claim 18. wherein the protrusion ^s disposed in an area between the dan^ping
are.a tcr holding the oplicai data recording mediurr; when reading or rfi-cording
data :n the signal recording iayer. and the signa! area for recoraing or reading
data in t^te signal recording layer
37. A m-jntifsctur;ng method for an opiica! data recording riedium according
lo claifn 36, wherem che proliusion is dtspcied lo an area vvichin 2 rnm to the
out.'Jide in the radial direction from the outside drcurr^ference edge o* tf*ie
clamping a^ea
38 A manufacturing method for an optica: dsla recording nediun'! accardir;g tc claim 18, wherein the protrusion is dlspcsad in the damping area for hold-ng the optical data recording mediumi when reading of recording dsta in the signal recording layer.
39 A {Tianufacturing methcd for an optical data recording medium according tc claim 16i, wherein the protrusion is formed tc a height of 0.05 mm to 0.5 mm

frofT the surface of ihe transparent protective layer.
AO. A frianufactLrirjg method for an optical data fccording (nedlLTn accciding to oaim 18, \vhero:n tne protrusion is formed to a i^^ight of 0 1 inra to 0.3 mm from the su.lace of the transparent protective layer.
41. A manufacturing method for an optica! data recoraipg medijrn according
to Claim 13 wfierein tne diameter of the center hoie ir> approxinialoiy 15 rnrn:
the protrusion is disposed to an area between a 17.5 mm inside diameter and 22-0 rnm oucsido diameter; and
the height of the protrusion abova the transparent protective iayer surface is C.3 mm or less.
42. A :rii3nufacturing method for ^r\ optica! data recording mediuna accciding to c airr 41. wr erein the heigh: of the protrusion referei-?ced to the surface u1 the cianping area for holding the cpltcal data recording rrteciium v/hen reading or recording data in the signal recording layer is 0 325 mm or less.
43. A manufacturing rp.ethod for an optical data recording medium according to claim 41 wherein the height of the protrusion referenced to the surface of the cianping area for holding the optical data recording medium when reading or recordinc data in the; signai recording layer is 0.2'^5 mm or less
44. A manufacturing method for an optica! data recording medium according to ciaim 41, v/herein the height of ihe protrusion referenced to the surface of the clamping ^^rea for holding the optica! data reccrding medium -^^hen reading or recording cata in the signal recording layer is 0.20 mm or less
45. A manufacturing methcd for an optical da:a reccrding medium according 10 ciaim 44, wherein the protrusion is disposed to an area betvveen a 17.5 mm inside diameter and 21.0 mm outsido diameter.

^6. A Glanipino method for a disoshapeci optica! data recording rnedium laving a signa' recorcing layer fci reciding ard/or writing data by emitting I'Oht isinq an opticai Jnesd ^//ith a 0.7 to 0 9 numeric apenure. and G 10 \jcn tc 20C jm :.hiCK rrcinsparenl protective layer disposed over the signal recording laye^
the optica! data recording rnsdium comprising a damping area on the outside of the center hole in the radiai directici for hciding the optica! data ecoraing riedium when reading or recording data in the signal recording layer, a signal area on the outside or the clamping area in the radiai direction for ecordJng or reading data in ihe signal recording layer, and a protrusion DrojBcting rorr the surface of the transparent protective layer in the clamping aren on thf= light-incidence side of the signal recording layer to which light is 3mr:ted for reading and/or writing information
the clamping method holding the optical data recording n-'-edium on both sid^s of the protrusion when -ecording or reading data in the signal recording layer of tne optical data recording medium.
47. A clamping method for an optical aata recording medium according to claim 45, v/herein the area for clamping on both sides of the protrusion on the ligh: indoence side is in a radiai ares with a radius of 11 rnm to 16.5 mvr.. 43 A damping method for an optical data recording medium according to ciaini 47, wherein the optica! cata .'t;aordtng medium is daniped by both holding the optio-s! data recording miedium on both sides of the protrusion on the light incidence side and holding the protrusion

49. A disc-shaped optical data recording medium, substantially as
hereinabove described and illustrated with reference to the accompanying drawings.


Documents:

701-CHE-2003 AMENDED PAGES OF SPECIFICATION 08-12-2011.pdf

701-CHE-2003 AMENDED CLAIMS 08-12-2011.pdf

701-CHE-2003 AMENDED CLAIMS 31-10-2011.pdf

701-CHE-2003 AMENDED PAGES OF SPECIFICATION 31-10-2011.pdf

701-CHE-2003 CORRESPONDENCE OTHERS 08-12-2011.pdf

701-CHE-2003 CORRESPONDENCE OTHERS 28-11-2011.pdf

701-CHE-2003 EXAMINATION REPORT REPLY RECEIVED 31-10-2011.pdf

701-CHE-2003 FORM-1 08-12-2011.pdf

701-CHE-2003 FORM-1 31-10-2011.pdf

701-CHE-2003 FORM-3 31-10-2011.pdf

701-CHE-2003 FORM-5 08-12-2011.pdf

701-CHE-2003 OTHER PATENT DOCUMENT 08-12-2011.pdf

701-CHE-2003 OTHER PATENT DOCUMENT 31-10-2011.pdf

701-CHE-2003 POWER OF ATTORNEY 31-10-2011.pdf

701-CHE-2003 CORRESPONDENCE OTHERS 30-12-2010.pdf

701-CHE-2003 CORRESPONDENCE PO.pdf

701-CHE-2003 FORM 13 07-05-2009.pdf

701-CHE-2003 FORM-18.pdf

701-che-2003 assignment.pdf

701-che-2003-abstract.pdf

701-che-2003-claims.pdf

701-che-2003-correspondence others.pdf

701-che-2003-correspondnece-others.pdf

701-che-2003-description(complete).pdf

701-che-2003-drawings.pdf

701-che-2003-form 1.pdf

701-che-2003-form 26.pdf

701-che-2003-form 3.pdf

701-che-2003-form 5.pdf


Patent Number 250326
Indian Patent Application Number 701/CHE/2003
PG Journal Number 52/2011
Publication Date 30-Dec-2011
Grant Date 23-Dec-2011
Date of Filing 04-Sep-2003
Name of Patentee PANASONIC CORPORATION
Applicant Address 1006, OAZA KADOMA, KADOMA-SHI OSAKA OSAKA 571-8501
Inventors:
# Inventor's Name Inventor's Address
1 HAYASHI KAZUHIRO 3-14-304 JOSHOJI-CHO KADOMA-SHI OSAKA 571-0063
2 OHNO EIJI 12-17 KITAYAMA 1-CHOME HIRAKATA-SHI OSAKA 573-0171
3 MOHRI MASANARI 4-1-1 KANOKODAI-MINAMI-MACHI KITA-KU, KOBE-SHI HYOGO 651-1514
PCT International Classification Number G11B7/26
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 P2002-260192 2002-09-05 Japan
2 P2003-68752 2003-03-13 Japan
3 P2002-320017 2002-11-01 Japan