Optical disk, thin plastic sheet, and method for affixing display sheet to disk substrate
View Patent ↗An optical disk is provided with a disk substrate having a recording layer formed on one surface of a substrate and a cover sheet applied over the recording layer; and a display sheet which is affixed to a surface of the disk substrate opposite to a surface covered with the cover sheet and which has substantially the same physical characteristic as that of the cover sheet. The display sheet and the cover sheet are substantially brought into coincidence with each other in terms a direction of heat contraction and a heat contraction rate.
1. An optical disk comprising:
a disk substrate having a recording layer formed on one surface of a substrate and a cover sheet applied over the recording layer; and
a display sheet which has substantially the same physical characteristic as that of the cover sheet and is affixed to a surface of the disk substrate opposite to a surface thereof covered with the cover sheet,
wherein the display sheet and the cover sheet substantially coincide with each other in terms of the direction of heat contraction and a heat contraction rate.
2. The optical disk according to claim 1 , wherein the thickness of the display sheet falls within a range of 0.05 to 0.3 mm.
3. The optical disk according to claim 1 , wherein a mark indicating the direction of heat contraction of the cover sheet is provided on the cover sheet, and a mark indicating the direction of heat contraction of the display sheet is provided on the display sheet.
4. An optical disk comprising:
a disk substrate having a recording layer formed on one surface of a substrate and a cover sheet applied over the recording layer; and
a display sheet which has substantially the same physical characteristic as that of the cover sheet and an adhesive surface affixed to peeling paper and is an accessory separate from the disk substrate,
wherein a mark indicating the direction of heat contraction of the cover sheet is provided on the cover sheet, and a mark indicating the direction of heat contraction of the display sheet is provided on the display sheet.
5. An optical disk comprising:
a disk substrate having a recording layer formed on one surface of a substrate and a cover sheet applied over the recording layer; and
a display sheet which has substantially the same physical characteristic as that of the cover sheet and is affixed to a surface of the disk substrate opposite to a surface thereof covered with the cover sheet,
wherein a mark indicating the direction of heat contraction of the cover sheet is provided on the substrate, and a mark indicating the direction of heat contraction of the display sheet is provided on the display sheet.
6. The optical disk according to claim 3 , wherein the mark corresponds to any one of a notch, a hole, and a slit section.
7. The optical disk according to claim 4 , wherein the mark corresponds to any one of a notch, a hole, and a slit section.
8. The optical disk according to claim 5 , wherein the mark corresponds to any one of a notch, a hole, and a slit section.
9. The optical disk according to claim 1 , wherein the display sheet is effectively formed from a two-layer structure; that is, upper and lower layers; the lower layer is a base layer including a fluorescent substance, and the upper layer is a image print layer provided on the base layer so as to cover the same.
10. The optical disk according to claim 9 , wherein the base layer is formed on the substrate in an isotropically uniform manner; the image print layer is formed from a plurality of blocks; and a space between the blocks is taken as a non-print section.
11. The optical disk according to claim 9 , wherein one print image is formed from a plurality of blocks on the image print layer, and a space between the blocks is taken as a non-print section having transparency to light.
12. The optical disk according to claim 9 , wherein different print images are formed into thumbnails in each block on the image print layer, and a space between said blocks is taken as a non-print section.
13. The optical disk according to claim 10 , wherein the non-print section is formed from a grid pattern, a radial pattern, a concentric pattern, or a combination thereof.
14. A method for affixing a display sheet to a disk substrate, the method including:
affixing a display sheet on a opposite surface of the disk substrate, which has a recording layer formed on a surface of a substrate and a cover sheet applied over the recording layer, the opposite surface being opposite to the surface of the disk substrate covered with the cover sheet,
wherein a mark, which is provided on at least either the cover sheet or the substrate and indicates a direction of heat contraction of the cover sheet, is caused to coincide with a mark, which is provided on the display sheet and indicates a direction of heat contraction of the display sheet, thus affixing the display sheet on the opposite surface of the disk substrate.
15. The optical disk according to claim 1 , wherein the physical characteristic is a physical dimension.
16. The optical disk according to claim 15 , wherein the physical dimension is a diameter.
17. The optical disk according to claim 1 , wherein the recording layer is formed of an organic-pigment-based material.
18. The optical disk according to claim 1 , wherein the cover sheet is formed from polycarbonate, TAC, or polyethylene terephthalate.
19. The optical disk according to claim 1 , wherein the display sheet is formed from polycarbonate, TAC, or polyethylene terephthalate.