Double-sided hybrid optical disk with surface topology
View Patent ↗An optical disk has a multi-layer tuned optical coating overlying both small bumps to store pre-recorded information and lands onto which information is written to and read. The optical coating includes a phase-change metal/alloy layer formed over the disk substrate and a dielectric layer formed over the phase-change layer. An optical disk according to the invention has specific topological features and sizes.
1. A first surface optical disk, comprising:
a substrate having a circular first surface and an opposing circular second surface, wherein the outer diameter of the first and second surface is approximately less than 50 mm;
a spiral pattern of bumps on a first portion of the circular first surface, wherein information is stored on and read from the bumps;
a second portion of the circular first surface defining a pattern of alternating lands and grooves, wherein each groove has inclined sidewalls, the inclined sidewalls for each groove being inclined approximately 45 degrees with respect to a bottom of the groove; and
a continuous multi-layer optical coating overlaying the bumps and the lands and grooves on the circular first surface, wherein the optical coating comprises:
a metal/alloy layer comprising tin, antimony and an element selected from the group consisting of indium, germanium, aluminum, and zinc; and
a dielectric layer overlaying the metal/alloy layer, the dielectric layer being configured to optically couple the metal/alloy layer to a laser beam incident on the dielectric layer.
2. The disk of claim 1 , wherein the outer diameter of the first and second surface is approximately 32 mm or less.
3. The disk of claim 1 , wherein the thickness of the substrate is approximately 0.6 mm±0.03 mm.
4. The disk of claim 1 , wherein the width of the bumps is between approximately 200 nm and 250 nm, the width measured at half-width full-max.
5. The disk of claim 1 , wherein the width of the bumps is 30%±3% of the track pitch of the bumps, the track pitch being the distance between the centerlines of adjacent bumps along the radial direction.
6. The disk of claim 1 , wherein the average distance between centerlines of adjacent bumps along the radial direction is 0.74 μm±0.03 μm.
7. The disk of claim 1 , wherein the height of the bumps is between approximately 80 nm and 90 nm.
8. The disk of claim 1 , wherein the distance between two of the bumps in a radially adjacent direction is between approximately 485 nm and 545 nm, measured at full width half max.
9. The disk of claim 1 , wherein the length of the bumps, covered by the optical coating, are multiples of 179 nm, the shortest length being a third multiple and the longest length being a fourteenth multiple.
10. The disk of claim 1 , wherein the height of each land is between approximately 80 nm and 90 nm.
11. The disk of claim 1 , wherein the width of each land is approximately 400 nm±50 nm, the width measured at half-width full-max.
12. The disk of claim 1 , wherein the width of each land is approximately 55% of the track pitch of the land, the track pitch being the distance between the centerlines of radially adjacent lands.
13. The disk of claim 1 , wherein the track pitch is between approximately 0.70 μm to 0.78 μm.
14. The disk of claim 1 wherein the lands define wobbles, the disk further comprising high frequency wobble marks (HFWMs) along the wobbles.
15. The disk of claim 14 , wherein the frequency of the HFWMs is approximately 3 to 5 times the frequency of the wobbles.
16. The disk of claim 14 , wherein the frequency of the HFWMs is between approximately 384 kHz to 641 kHz.
17. The disk of claim 14 , wherein the amplitude of the wobbles and HFWMs is within ±25% of each other.
18. The disk of claim 1 , wherein the dielectric layer comprises silicon oxynitride.