CN1311435C - Rewritable optical record carrier - Google Patents
Rewritable optical record carrier Download PDFInfo
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- CN1311435C CN1311435C CNB200380104814XA CN200380104814A CN1311435C CN 1311435 C CN1311435 C CN 1311435C CN B200380104814X A CNB200380104814X A CN B200380104814XA CN 200380104814 A CN200380104814 A CN 200380104814A CN 1311435 C CN1311435 C CN 1311435C
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- China
- Prior art keywords
- record carrier
- optical record
- layer
- rewritable optical
- dielectric layer
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Abstract
The invention relates to a rewritable optical record carrier (100) comprising a recording stack (110) of layer (114), a recording layer comprising a phase-change recording material, and a second dielectric layer (116), having a thermal barrier layer (122) arranged adjacent to said first dielectric layer.
Description
The present invention relates to a kind of rewritable optical record carrier, comprise one by a plurality of layers of recording stack of forming, this multilayer comprises the first dielectric layer (I
1), comprise the recording layer and the second dielectric layer (I of phase-change recording material (PC)
2).
Make a general survey of all known optical record mediums rewritten, for example CD-RW, DVD-RAM, DVD-RW, DVD+RW and Blu-ray CD (BD) have all been used a kind of recording stack that comprises this phase-change recording lamination.Usually the PC layer is clipped in two dielectric ZnS-SiO
2In the lamination between the layer.At present, be alloy for the medium that can wipe the phase-change recording selection, as add the alloy that In, Ge and/or Ag form by Sb and Te with wear-resisting polycrystalline structure.Side (I at this recording stack
2-side) on, is provided with one typically by the specular layer of forming such as the metal of gold, silver or aluminium.Under the situation of CD/DVD, recording stack is arranged to its opposite side (I
1-side) in substrate such as polycarbonate, and with on the opposite side of an overlayer attached to specular layer.The laser beam that writes according to the tracer signal modulation (at first is I from base side
1-side) incides recording medium.Under the situation of BD, recording stack is arranged to its specular layer (I
2-side) in substrate, and with an overlayer attached to the recording stack (I relative with specular layer
1-side) on.Writing laser beam then (at first is I from this side
1-side) incides recording medium.
Light beam is focused on the recording stack in two kinds of situations.When CD moved with respect to the laser beam that focuses on, laser beam was recorded layer basically and absorbs.Therefore, spot heating alloy.When temperature after a while surpasses its fusing point (about 500 ℃ to 700 ℃), phase-change material can change into amorphous state.By adjacent dielectric layers quick heat radiating cooled alloy rapidly, thereby make amorphous phase stable.Therefore writing mark keeps along track.Apply the power that reduces to laser beam and can allow to wipe the mark that writes.Therefore, recording layer is heated to about 200 ℃ temperature, and impels and change back to crystalline phase mutually.Because atom must keep long enough so that crystallization again in the temperature that raises, though recrystallization is a process quite slowly, the amorphization in the PC medium can be very fast.
Usually, lamination has the high low signal polarity that arrives, and promptly it has high reflection potential in crystal phase (ground state), and this reflection potential can reduce in noncrystal phase (writing attitude).Therefore, the reading beam that focuses on the described recording stack is reflected with different intensity on lamination, and this intensity depends on whether this electron beam clashes into amorphous mark (pit) that writes or the crystalline region (face) that does not write.
Therefore; dielectric layer and reflection horizon have several effects: the protection recording layer is avoided physical damage; but form the whole structure of an optically modulating; this structure has optimized reflectivity and/or absorptivity (optical property), and in order to cool off and better avoid the thermal characteristics of the protection permission adjustment CD of pyrolytic damage fast.
As what seen in Fig. 3, optical property depends on the first medium thickness d periodically
1Especially, noncrystal and crystal reflection is at some d
1The value place has minimum value and maximal value.This cycle can be represented with following formula
d
1＝(m*λ)/(2*n) (1)
Wherein m is an integer, and λ is a Wavelength of Laser, and you n is I
1The refractive index of layer material.Optical contrast is the difference between crystal reflection and the amorphous reflection, utilizes crystal reflection to make its standardization, and therefore, the optics contrast changed with the identical cycle.
The PC layer has different refractive indexes in its crystal attitude with amorphous state.Therefore PC layer that reflectivity is played a major role and the refractive index mismatch between the adjacent dielectric layers can cause the phase shift between noncrystal and the crystal reflection rate.At as shown in Figure 3 height under the situation of low signal polarity, I
1The thickness d of layer
1Be advantageously selected to and make amorphous reflection near its minimum value.Crystalline ground state area (face) locate intensity of light reflected according to the number percent of incident beam with square representing.Triangle table is shown in the light that percentile amorphous write state zone (pit) is reflected.Circle represent percentile crystal and noncrystal between optical contrast, thus, optical contrast is represented the decay of the light that is reflected during by the pit of crystalline state reflectance standardsization when incident light bump.Therefore, when amorphous reflection during, can obtain maximum optical contrast and best signal modulation near its minimum value.The optical phase shift between crystalline state and the amorphous state represented in cross.Thus, according to Fig. 3, as first approximation, optical property does not depend on the peaked order of magnitude of optical contrast.Up to the present, m can be an arbitrary parameter.
Yet the laser beam that is produced by the writing station with conventional optical writing head is focused into has short focal length.The incident angle of light beam is by changing at incidence point on its width, referring to Fig. 4.Laser beam before 401 expressions focus among Fig. 4, the 402nd, condenser lens, the 403rd, the laser beam of the convergence after focusing on, the 404th, the laser beam (401 vertical with the surface 405 of recording stack 406,403) center line, the 407th, incident angle (α) more accurately, is to be in light in the focused beam and the angle between the normal incidence.For example, the average angle α of the convergent laser bundle of BD system is about 35 °.
Utilize this method, by the effective optical path l of dielectric layer
EffAccording to following formula along with angle [alpha] changes
l
eff(α)＝l
0/cos(α) (2)
L wherein
0Expression is perpendicular to the light path on surface.As what from equation 2, seen, for predetermined normal path l
0, active path length increases along with angle [alpha].For example, if consider 35 ° angle, then active path length has increased 22%.The difference of path conversely
Δl＝l
0*(1/cos(α)-1) (3)
Can cause phase shift, and therefore reduce the optical property of CD.That is to say that dielectric layer is thin more, optical property can be regulated well more.Therefore, from the viewpoint of optical property, the first medium thickness d
1Be chosen to must approach as far as possible-or on the meaning of volume reflection minimum, its thickness is chosen to first minimum value (m=1).
Although writeable optical record carrier increases aspect data capacity gradually, the numerical aperture of object lens has also increased, and optical maser wavelength has reduced simultaneously.For example, (CD, NA=0.45, λ=780nm) increase to 4.7GB, and (λ=670nm) increases to 25GB (BD, NA=0.85, λ=405nm) to the conceptual data capacity at last for DVD, NA=0.65 from 650MB.Under the situation of BD system, in order to obtain acceptable optical property, the typical thickness of first dielectric layer only is about 40nm.Finally, for having more short wavelength's UV-record, I
1Layer must be thinner.
But from thermo-lag viewpoint, first dielectric layer has been protected recording layer on the one hand, and has protected (polycarbonate) substrate (CD/DVD) or overlayer (BD) to avoid pyrolytic damage on the other hand.If select too thinly, the heat that just can not reduce at write/erase fully and produce when arriving substrate/overlayer.Therefore may surpass the melt temperature of substrate/covering layer material in temperature, thereby cause optical record carrier to damage to substrate/tectal interface.This damage will cause read output signal to reduce, and increase noise and error rate.Therefore first dielectric layer must be selected enough thickly.Perhaps on the meaning of volume reflection minimum, d
1Be chosen to minimum value m＞1.So, be the work of opposition to optimal heat protection adjacent base (under the situation of CD/DVD) or adjacent cover layer (under the situation of BD) and best optical property.
Therefore, the purpose of this invention is to provide a kind of rewritable optical record carrier, it has the stack-design of good optical characteristic, thereby sufficient thermal protection is provided.
According to a first aspect of the invention, can achieve this end as the optical record carrier of in opening paragraph, describing rewritten, it is characterized in that contiguous first dielectric layer layout of thermofin by one.
According to a second aspect of the invention, its another kind that has constituted a first aspect of the present invention is arranged, this can rewrite the substrate of lamination that optical record carrier also comprises a described multilayer of carrying, and this is multilayer laminated to have the described thermofin that is arranged between described first dielectric layer and the described substrate.
According to a third aspect of the invention we, its another kind that has constituted a second aspect of the present invention arranges that the refractive index of described thermofin is near the refractive index of described substrate.
According to a forth aspect of the invention, its another kind that has constituted a first aspect of the present invention arranges that described record carrier also comprises one attached to the overlayer on the described thermofin.
According to a fifth aspect of the invention, its another kind that has constituted a fourth aspect of the present invention arranges that the refractive index of described thermofin is near described tectal refractive index.
According to a sixth aspect of the invention, its constituted of the present invention second or the another kind of the third aspect arrange that described base material is polycarbonate or PMMA.
According to a seventh aspect of the invention, its another kind that has constituted the of the present invention the 4th or the 5th aspect arranges that described overlayer is polycarbonate or transparent polymer resin.
According to an eighth aspect of the invention, it has constituted any one another kind of layout in first to the 7th aspect of the present invention, and described insulating layer material comprises the SiO as principal ingredient
2, Al
2O
3
According to a ninth aspect of the invention, it has constituted of the present invention first and any onely to the eight aspect has another kind ofly arranged that described first and second dielectric layer material comprise or its potpourri: ZnS, SiO in the following component
2, Si
3N
4, Al
2O
3Or Ta
2O
5
According to the tenth aspect of the invention, it has constituted any one another kind of layout in first to the 9th aspect of the present invention, and described phase-change recording material comprises the potpourri of Ge, In, Sb and Te.
By following description of the preferred embodiment of the present invention, above and other objects of the present invention, feature and advantage will be conspicuous in conjunction with the accompanying drawings, wherein:
Fig. 1 shows the viewgraph of cross-section according to the optical record carrier rewritten of the first embodiment of the present invention;
Fig. 2 shows the viewgraph of cross-section of the optical record carrier rewritten according to a second embodiment of the present invention;
Fig. 3 shows the optical property that depends on first medium thickness; And
Fig. 4 shows the light path of convergent laser bundle.
As what in Fig. 1, seen, comprise a recording stack 110 according to the optical record carrier rewritten 100 of the first embodiment of the present invention, it is clipped in the first dielectric I by one
1The layer 114 and second dielectric I
1Record PC layer 112 between the layer 116 is formed.Dielectric layer material can comprise or its combination: ZnS, SiO in the following component
2, Si
3N
4, Al
2O
3Or Ta
2O
5, for example (ZnS)
80(SiO
2)
20The PC layer can be added In, Ge and/or Ag forms by Sb and Te, for example GeInSbTe.At the top of record carrier 100, the direction of incident beam represents with arrow 118, can find that substrate 120 typically is made up of polycarbonate or PMMA or analog.With thermofin 122 deposits (put upside down and illustrate) in substrate.According to I
1-PC-I
2Order with recording stack 110 laminations (illustrating below) on thermofin.Therefore, will be as the close I relative of the thermofin of good heat insulator with the PC layer
1Layer is arranged, reduces heat thus and propagates towards substrate 120 through 114 from writing down PC layer 112.Specular layer (mirror layer) 124 comprises aluminium, silver or gold or its potpourri, for example has the Ti of certain percentage or the Al of gold, and with specular layer deposit (illustrating below) at I
2On the layer 116, formed a MIPI-lamination thus.Avoid physical damage for the protective glass surface layer at last, specular layer 124 can be coated with a layer 126, this layer by polycarbonate or by transparent polymer resin/coat with lacquer for example analog such as Sylgard 184 form.Layout according to Fig. 1 is according to DVD-and the rewritable standard stack design of CD.
Typically the optical record carrier rewritten according to a second embodiment of the present invention 200 as shown in Figure 2 is according to the BD stack-design, but specular layer 224 is deposited in the substrate 226 (bottom-up).Recording stack 210 is according to I
2-PC-I
1Order be deposited on the specular layer.Thermofin 222 is attached to the I of recording stack 210
1On the layer 214.At last, cover thermofin with overlayer 220.The incident beam of representing with arrow 218 incides the lamination on the cover layer side in this case.
In two embodiment according to Fig. 1 and Fig. 2, I
1-layer can comprise a sandwich construction, wherein from phase change layer I farthest
1The sublayer of-multilayer has the refractive index different with substrate/overlayer.
Insulating layer material in these two embodiment is chosen to have in the write/erase laser beam at setted wavelength and the abundant approaching refractive index of substrate/overlayer.For example, when the covering layer material when in a second embodiment was polycarbonate or Sylgard 184, the wavelength of laser beam was 405nm, and as what provide in the BD system, the refractive index of covering layer material is 1.5.The suitable material that is used for thermofin 122 so may be SiO
2, its wavelength place at 405nm also has 1.5 refractive index, and has low relatively specific guide heating rate.Regulate heat insulation by the suitable thickness of selecting thermofin 122 simply then, and can not reduce the optical property of lamination.Al
2O
3It also is a kind of suitable material that is used for thermofin 122.And thermofin can be a sandwich construction.Therefore, I
2Layer thickness can be for required the approaching that require of best optics and thermal behavior.
Should note the invention is not restricted to top preferred embodiment.Can use other recording layer material, dielectric layer material, insulating layer material, reflector material, base material and/or covering layer material.In addition, the invention is not restricted to have the optical record carrier of single recording layer structure as described herein.Can provide according to the present invention and to comprise two or surpass two pluratity of recording layers structures with recording layer of optical characteristics.Thus, can provide two or more as described herein recording stacks, two recording stacks or only one of them comprises a thermofin.
Claims (10)
1. a rewritable optical record carrier (100,200) comprises one by a plurality of layers of recording stack of forming (110,210), and this multilayer comprises
First dielectric layer (I14,214),
The recording layer that comprises phase-change recording material,
Second dielectric layer (116,216), and
Be arranged on the specular layer (124,224) on the second dielectric layer side of described recording stack (110,210),
It is characterized in that thermofin (122,222) is close to described first dielectric layer and described specular layer (124,224) is relatively arranged.
2. rewritable optical record carrier as claimed in claim 1 (100), it is characterized in that this can rewrite the substrate (120) of lamination that optical record carrier (100) also comprises a described multilayer of carrying, this is multilayer laminated to have the described thermofin (122) that is arranged between described first dielectric layer (114) and the described substrate (120).
3. rewritable optical record carrier as claimed in claim 2 (100) is characterized in that the refractive index of the refractive index of described thermofin (122) near described substrate.
4. rewritable optical record carrier as claimed in claim 1 (200) is characterized in that described record carrier (200) also comprises one attached to the overlayer (220) on the described thermofin (222).
5. rewritable optical record carrier as claimed in claim 4 (200), the refractive index that it is characterized in that described thermofin (222) is near described tectal refractive index.
6. as claim 2 or 3 described rewritable optical record carriers, it is characterized in that described base material is polycarbonate or PMMA.
7. as claim 4 or 5 described rewritable optical record carriers (200), it is characterized in that described covering layer material is polycarbonate or transparent polymer resin.
8. as the described rewritable optical record carrier of any one claim (100,200) among the claim 1-5, it is characterized in that described insulating layer material comprises the SiO as principal ingredient
2Or Al
2O
3
9. as the described rewritable optical record carrier of any one claim (100,200) among the claim 1-5, it is characterized in that described first and second dielectric layer material comprise or its potpourri: ZnS, SiO in the following component
2, Si
3N
4, Al
2O
3Or Ta
2O
5
10. as the described rewritable optical record carrier of any one claim (100,200) among the claim 1-5, it is characterized in that described phase-change recording material comprises the potpourri of Ge, In, Sb and Te.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| EP02080275.7 | 2002-12-13 | ||
| EP02080275 | 2002-12-13 | ||
| EP03100329.6 | 2003-02-13 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1720572A CN1720572A (en) | 2006-01-11 |
| CN1311435C true CN1311435C (en) | 2007-04-18 |
Family
ID=35931780
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB200380104814XA Expired - Fee Related CN1311435C (en) | 2002-12-13 | 2003-12-03 | Rewritable optical record carrier |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1311435C (en) |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH04195831A (en) * | 1990-11-28 | 1992-07-15 | Hitachi Ltd | Material for optical information recording, reproducing and erasing |
| WO2000063899A1 (en) * | 1999-04-19 | 2000-10-26 | Teijin Limited | An optical recording medium and method for using same |
| US6251492B1 (en) * | 1998-04-10 | 2001-06-26 | Teijin Limited | Optical recording medium |
-
2003
- 2003-12-03 CN CNB200380104814XA patent/CN1311435C/en not_active Expired - Fee Related
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH04195831A (en) * | 1990-11-28 | 1992-07-15 | Hitachi Ltd | Material for optical information recording, reproducing and erasing |
| US6251492B1 (en) * | 1998-04-10 | 2001-06-26 | Teijin Limited | Optical recording medium |
| WO2000063899A1 (en) * | 1999-04-19 | 2000-10-26 | Teijin Limited | An optical recording medium and method for using same |
Also Published As
| Publication number | Publication date |
|---|---|
| CN1720572A (en) | 2006-01-11 |
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