1. An optical recording medium to be processed by a light beam having a wavelength \u03bb and a lens having a numerical aperture NA, comprising:
one of a track and a pit array,
wherein a width of one of the track and the pit satisfies a condition 0.480\u2266TP\xd7NA\u03bb<1.026.
2. The medium according to claim 1, wherein the wavelength \u03bb is 405 nm, and the numerical aperture NA is 0.65.
3. The medium according to claim 1, wherein the wavelength \u03bb is 405 nm, and the numerical aperture NA is 0.85.
4. The medium according to claim 1, which further comprises a recording film corresponding to the track, and
in which the recording film contains at least Ge, Sb, and Te, and a composition GexSbyTez contained in the recording film is a composition that satisfies x+y+z=100 and is defined by x=55z=45, x=45z=55, x=10y=28z=42, and x=10y=36z=54 on a GeSbTe ternary phase diagram.
5. The medium according to claim 4, wherein the composition contained in the recording film is partially substituted with bismuth (Bi) andor indium (In) andor tin (Sn), the composition (Ge(1-w)Snw)x(Sb(1-v)(Bi(1-u)Inu)v)yTez after substitution satisfies x+y+z=100, and w, v, and u satisfy conditions 0\u2266w<0.5, 0<v<1, and 0\u2266u\u22660.7.
6. The medium according to claim 1, which further comprises a recording film corresponding to the track, and
in which the recording film contains at least Ge, Bi, and Te, and a composition GexBiyTez contained in the recording film is a composition that satisfies x+y+z=100 and is defined by x=55z=45, x=45z=55, x=10y=28z=42, and x=10y=36z=54 on a GeBiTe ternary phase diagram.
7. The medium according to claim 1, which further comprises a recording film corresponding to the track, and
in which the recording film contains at least Ge, Sb, Te, and nitrogen (N), the composition GexSbyTez contained in the recording film satisfies x+y+z=100 in a composition region defined by x=55z=45, x=45z=55, x=10y=28z=42, and x=10y=36z=54 on a GeSbTe ternary phase diagram, and nitrogen (N) is added in 1 to 5 at. % to a GeSbTe compound in the composition region.
8. The medium according to claim 7, wherein the composition contained in the recording film is partially substituted with bismuth (Bi) andor indium (In) andor tin (Sn), the composition (Ge(1-w)Snw)x(Sb(1-v)(Bi(1-u)Inu)v)yTez after substitution satisfies x+y+z=100, and w, v, and u satisfy conditions 0\u2266w<0.5, 0<v<1, and 0\u2266u\u22660.7, and
N is added in 1 to 5 at. % to one of GeSnSbTe, GeSnSbTeIn, GeSbTeIn, GeSbTeBiIn, GeSbSnTeBiIn, GeSbTeBi, GeSnSbTeBi, and GeSnSbTeBiIn compounds corresponding to the composition after substitution.
9. The medium according to claim 1, which further comprises a recording film corresponding to the track, and
in which the recording film contains at least Ge, Bi, Te, and nitrogen (N), the composition GexBiyTez contained in the recording film satisfies x+y+z=100 in a composition region defined by x=55z=45, x=45z=55, x=10y=28z=42, and x=10y=36z=54 on a GeBiTe ternary phase diagram, and nitrogen (N) is added in 1 to 5 at. % to a GeBiTe compound in the composition region.
10. The medium according to claim 1, which further comprises a recording film corresponding to the track, and
in which the recording film contains at least Sb and Te, and in a composition SbaTe1-a contained in the recording film, a satisfies 0.6\u2266a\u22660.81.
11. The medium according to claim 1, which further comprises a recording film corresponding to the track, and
in which the recording film contains at least Ga and Sb, and in a composition GabSb1-b contained in the recording film, b satisfies 0.09\u2266b\u22660.35.
12. The medium according to claim 1, which further comprises a recording film corresponding to the track, and
in which the recording film contains at least In and Sb, and in a composition IncSb1-c contained in the recording film, c satisfies 0.15\u2266c\u22660.4.
13. The medium according to claim 1, which further comprises a recording film corresponding to the track, and
in which the recording film contains at least Ga and Sb, and in a composition GadSb1-d contained in the recording film, d satisfies 0.10\u2266d\u22660.35.
14. The medium according to claim 1, which further comprises a recording film corresponding to the track, and
in which the recording film contains at least Ga, In, and Sb, and in a composition (InSb)e(GaSb)1-e contained in the recording film, e satisfies 0\u2266e\u22661.
15. The medium according to claim 4, wherein at least one of layers in contact with the recording film is an interface layer selected from the group consisting of GeN, GeCrN, ZrO2+Cr2O3, ZrSiO4, ZrO2-xNx containing Y2O3, ZrO2-xNx+Cr2O3 containing Y2O3, and ZrSiO4-xNx.
16. The medium according to claim 10, wherein at least one of layers in contact with the recording film is a layer selected from the group consisting of SiN, GeN, and SiC layers.
17. An information playback apparatus comprising:
a laser which emits a light beam having a wavelength \u03bb; and
an objective lens which has a numerical aperture NA and focuses the light beam emitted from the laser onto an optical recording medium,
wherein the information playback apparatus plays back information from an optical recording medium which has one of a track and a pit and satisfies a condition 0.480\u2266track or pit width TP\xd7NA\u03bb<1.026.
18. The apparatus according to claim 17, wherein the wavelength \u03bb is 405 nm, and the numerical aperture NA is 0.65.
19. The apparatus according to claim 17, wherein the wavelength \u03bb is 405 nm, and the numerical aperture NA is 0.85.
20. An information playback method comprising:
emitting a light beam having a wavelength \u03bb; and
focusing the emitted light beam onto an optical recording medium via an objective lens having a numerical aperture NA and playing back information from an optical recording medium which has one of a track and a pit and satisfies a condition 0.480\u2266track or pit width TP\xd7NA\u03bb<1.026.
21. An information recording apparatus comprising:
a laser which emits a light beam having a wavelength \u03bb; and
an objective lens which has a numerical aperture NA and focuses the light beam emitted from the laser onto an optical recording medium,
wherein the information recording apparatus records information on an optical recording medium which has one of a track and a pit and satisfies a condition 0.480\u2266track or pit width TP\xd7NA\u03bb<1.026.
22. The apparatus according to claim 21, wherein the wavelength \u03bb is 405 nm, and the numerical aperture NA is 0.65.
23. The apparatus according to claim 21, wherein the wavelength \u03bb is 405 nm, and the numerical aperture NA is 0.85.
24. The apparatus according to claim 19, wherein the laser emits the light beam having the wavelength \u03bb based on one of a waveform and a pulse train, in which a rise time of an optical pulse falls within a range of 0.1 to 0.9 ns (inclusive).
25. An information recording method comprising:
emitting a light beam having a wavelength \u03bb; and
focusing the emitted light beam onto an optical recording medium via an objective lens having a numerical aperture NA and recording information on an optical recording medium which has one of a track and a pit and satisfies a condition 0.480\u2266track or pit width TP\xd7NA\u03bb<1.026.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A method for producing a cellulose ether comprising:
contacting a cellulose ether with a first oxidizing agent and an acid to form a mixture;
heating the mixture;
neutralizing the mixture;
after the step of neutralizing the mixture, adding at least a second oxidizing agent to the mixture; and
forming a cellulose ether having a viscosity from 1.2 cP to 50 cP measured at 2% by weight aqueous solution at 20\xb0 C. and an APHA value from 1 to 100.
2. The method of claim 1 comprising heating the mixture at a temperature from 70\xb0 C. to 100\xb0 C. for 1 to 20 hours.
3. The method of claim 1 comprising heating the mixture after addition of the second oxidizing agent.
4. The method of claim 1 comprising maintaining the water content of the mixture between 3% and 6% by weight.
5. A method for coating a substrate comprising:
applying an aqueous solution of a very low viscosity cellulose ether according to claim 1 on the substrate; and
forming a coating comprising the very low viscosity cellulose ether on the substrate.
6. The method of claim 5 wherein the aqueous solution has an APHA value from 1 to 20.
7. The method of claim 5 wherein the aqueous solution comprises at least 10% by weight of the very low viscosity cellulose ether.
8. A method for producing a cellulose ether comprising: contacting a cellulose ether with a first oxidizing agent and an acid to form a mixture;
heating the mixture;
neutralizing the mixture, and then, adding at least a second oxidizing agent to the mixture; and
forming a very low color cellulose ether having an APHA value from 1 to 20 and a viscosity less than about 3 cP measured at 2% by weight aqueous solution at 20\xb0 C.
9. The method of claim 8 comprising performing the heating at a point in time selected from the group consisting of before the adding, after the adding, and combinations thereof.
10. The method of claim 8 comprising neutralizing the mixture after the heating.