1. A method for fabricating a diffraction-type 3D display element, comprising:
cleaning a substrate;
undertaking a first etching process, wherein the first etching process employs a first mask which includes a plurality of first light-shielding zones and a plurality of first light-transparent zones interlaced with the plurality of first light-shielding zones to form a plurality of first flattened areas and a plurality of first recessed areas interlaced with the plurality of first flattened areas on the substrate;
aligning a second mask which includes a plurality of second light-shielding zones and a plurality of second light-transparent zones interlaced with the plurality of second light-shielding zones, wherein the second mask is aligned to borders of the first flattened areas and the first recessed areas to make each of the first flattened areas correspond to a combination of the second light-transparent zone and the second light-shielding zone, and to make each of the first recessed areas correspond to another combination of the second light-transparent zone and the second light-shielding zone; and
undertaking a second etching process, wherein the second etching process employs the second mask to form second recessed areas on part of each first flattened area and part of each first recessed area that correspond to the second light-transparent zones, and wherein each second recessed area is formed at a depth smaller than that of the first recessed area to form a four-step structure.
2. The method for fabricating a diffraction-type 3D display element according to claim 1, wherein the depth of the second recessed area is half the depth of the first recessed area.
3. The method for fabricating a diffraction-type 3D display element according to claim 1 further comprising steps:
aligning a third mask, wherein the third mask is aligned to borders of the first flattened areas, the first recessed areas and the second recessed areas; and
undertaking a third etching process, wherein the third mask is used to undertake the third etching process to respectively form third recessed areas on the first flattened areas, the second recessed areas in the first flattened areas, the first recessed areas, and the second recessed areas in the first recessed areas, and wherein each third recessed area is formed at a depth smaller than that of the second recessed area to form an eight-step structure.
4. The method for fabricating a diffraction-type 3D display element according to claim 3, wherein the depth of the third recessed area is half the depth of the second recessed area.
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 stretchable book cover for insertion of a book therein, comprising: outer panel portions for covering the front cover, back cover and spine portions of said book; a first in-folded panel portion for covering the inside of the front cover, wherein said first in-folded panel portion includes a lateral triangular panel, a top panel having four sides, and a bottom panel having four sides, wherein at least one side of said lateral triangular panel is joined to a side of said top panel, at least one side of said lateral triangular panel is joined to a side of said bottom panel, and at least one side of said top panel is joined to at least one side of said bottom panel to form a pocket, with said pocket having an elongated aperture extending substantially parallel with said book spine; and a second in-folded panel portion for covering the inside of the back cover, wherein said second in-folded panel portion includes a second lateral triangular panel, a second top panel having four sides, and a second bottom panel having four sides, wherein at least one side of said second lateral triangular panel is joined to a side of said second top panel, at least one edge side of said second lateral triangular panel is joined to a side of said second bottom panel, and at least one side of said second top panel is joined to at least one side of second said bottom panel to form a pocket, with said pocket having an elongated aperture extending substantially parallel with said book spine.
2. The stretchable book cover as specified in claim 1 wherein each of said lateral triangular panel, top panel, and bottom panel have side portions joined by fastening means selected from the group consisting of stitching, taping, gluing, ultrasonic welding, R.F welding and heat sealing.
3. The stretchable book cover as specified in claim 1 wherein said book cover comprises a fabric comprised of stretchable and elastic threads.
4. The stretchable book cover as specified in claim 1 wherein said outer panel portions have indicia in the form of a plurality of rhinestonenail head transfers forming a design on said outer panel portion.
5. A stretchable book cover for insertion of a book therein, comprising: outer panel portions for covering the front cover, back cover and spine portions of said book; a first in-folded panel portion for covering the inside of the front cover, wherein said first in-folded panel portion includes a lateral triangular panel, a top panel having four sides, and a bottom panel having four sides wherein at least one side of said lateral triangular panel is joined to a side of said top panel, at least one side of said lateral triangular panel is joined to a side of said bottom panel, and at least one side of said top panel is joined to at least one side of said bottom panel to form a first pocket; and a second in-folded panel portion for covering the inside of the back cover, wherein said second in-folded panel portion includes a second lateral triangular panel, a second top panel having four sides, and a second bottom panel having four sides, wherein at least one side of said second lateral triangular panel is joined to a side of said second top panel, at least one side of said second lateral triangular panel is joined to a side of said second bottom panel, and at least one side of said second top panel is joined to at least one side of second said bottom panel to form a second pocket, wherein each pocket has an elongated aperture extending substantially parallel with said book spine, wherein said cover comprises a unitary polygon of pliable material with extended upper and lower edges, with each edge bisected by said aperture, which is defined as a slot of predetermined width, extending at right angles to the respective upper and lower edge to permit insertion of said front and back covers of said book into the cover.
6. The stretchable book cover as specified in claim 5 wherein each of said lateral triangular panels, top panels, and bottom panels have side portions joined by fastening means selected from the group consisting of stitching, taping, gluing, ultrasonic welding, R.F welding and heat sealing.
7. The stretchable book cover as specified in claim 5 wherein said book cover comprises a fabric comprised of stretchable and elastic threads.
8. The stretchable book cover as specified in claim 5 wherein said outer panel portions have indicia in the form of a plurality of rhinestonenail head transfers forming a design on said outer panel portion.