1. An extrusion apparatus for making a multilayer article, comprising:
a first section;
a second section; and
a plurality of discs between the first and second sections, each of the discs having at least one passageway configured to permit fluid flow therethrough in a flow direction, wherein
the plurality of discs comprises first and second discs having an outward cone shaped portion and third and fourth discs having an inward cone shaped portion;
the outward cone shaped portion of the first disc mates the inward cone shaped portion of the third disc so that, when mated, the first and third discs form a first mated pair of discs;
the outward cone shaped portion of the second disc mates the inward cone shaped portion of the fourth disc so that, when mated, the second and fourth discs form a second mated pair of discs;
the first, third, second and fourth discs are arranged in order along the flow direction; and
a thickness of at least one of the discs in the flow direction is about one inch or less.
2. The apparatus of claim 1, wherein the passageway of each disc is spiral shaped.
3. The apparatus of claim 1, wherein the thickness of the at least one disc in the flow direction is about 0.75 inch or less.
4. The apparatus of claim 1, wherein the thickness of the at least one disc in the flow direction is about 0.5 inch or less.
5. The apparatus of claim 1, wherein the thickness of the at least one disc in the flow direction is about 0.4 inch or less.
6. The apparatus of claim 1, wherein the thickness of the at least one disc in the flow direction is about 0.3 inch or less.
7. The apparatus of claim 1, wherein the thickness of the at least one disc in the flow direction is about 0.2 inch or less.
8. The apparatus of claim 1, wherein the thickness of the at least one disc in the flow direction is about 0.15 inch or less.
9. The apparatus of claim 1, wherein the thickness of the at least one disc in the flow direction is about 0.1 inch or less.
10. The apparatus of claim 1, wherein each of the discs has a thickness in the flow direction that is about one inch or less.
11. The apparatus of claim 1, wherein the apparatus is a crosshead.
12. The apparatus of claim 1, wherein the apparatus is configured to be used in the fabrication of an article selected from the group consisting of multilayer medical balloons, multilayer tubes, and multilayer catheter shafts.
13. The apparatus of claim 1, wherein the apparatus is configured to be used in the fabrication of a multilayer medical balloon.
14. The apparatus of claim 1, wherein the spiral has a width of from about 0.05 inch to about 0.75 inch.
15. The apparatus of claim 1, wherein the at least one of the discs does not have a cone-shaped portion.
16. An extrusion apparatus for making a multilayer article, comprising:
a first section;
a second section; and
a plurality of discs between the first and second sections, each of the discs having at least one passageway configured to permit fluid flow therethrough in a flow direction, wherein
the plurality of discs comprises first and second discs having an outward cone shaped portion and third and fourth discs having an inward cone shaped portion;
the outward cone shaped portion of the first disc mates the inward cone shaped portion of the third disc so that, when mated, the first and third discs form a first mated pair of discs;
the outward cone shaped portion of the second disc mates the inward cone shaped portion of the fourth disc so that, when mated, the second and fourth discs form a second mated pair of discs;
the first, third, second and fourth discs are arranged in order along the flow direction; and
a thickness of at least one of the discs in the flow direction is about one inch or less.
17. The apparatus of claim 16, wherein the at least one of the discs does not have a cone-shaped portion.
18. An extrusion apparatus for making a multilayer article, comprising:
a first section;
a second section; and
a plurality of discs between the first and second sections, each of the discs having at least one passageway configured to permit fluid flow therethrough in a flow direction,
wherein a thickness of at least one of the discs in the flow direction is about one inch or less, and at least one of the discs includes a cone shaped portion extending substantially parallel to the flow direction.
19. The apparatus of claim 18, wherein all but one of the discs includes a cone shaped portion extending substantially parallel to the flow direction.
20. The apparatus of claim 18, wherein the thickness of the at least one disc in the flow direction is about 0.75 inch or less.
21. The apparatus of claim 18, wherein the thickness of the at least one disc in the flow direction is about 0.5 inch or less.
22. The apparatus of claim 18, wherein the thickness of the at least one disc in the flow direction is about 0.4 inch or less.
23. The apparatus of claim 18, wherein the thickness of the at least one disc in the flow direction is about 0.3 inch or less.
24. The apparatus of claim 18, wherein the thickness of the at least one disc in the flow direction is about 0.2 inch or less.
25. The apparatus of claim 18, wherein the thickness of the at least one disc in the flow direction is about 0.15 inch or less.
26. The apparatus of claim 18, wherein the thickness of the at least one disc in the flow direction is about 0.1 inch or less.
27. The apparatus of claim 18, wherein each of the discs has a thickness in the flow direction that is about one inch or less.
28. The apparatus of claim 18, wherein the apparatus is a disc head extrusion apparatus.
29. The apparatus of claim 18, wherein the apparatus is configured to be used in the fabrication of an article selected from the group consisting of multilayer medial balloons, multilayer tubes and catheter shafts.
30. The apparatus of claim 18, wherein the apparatus is configured to be used in the fabrication of a multilayer medical balloon.
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 light emitting device comprising:
a substrate;
a first semiconductor layer, a second semiconductor layer, and an active layer disposed therebetween, arranged on the substrate; and
a refractive index adjustment layer arranged on the first semiconductor layer, the refractive index adjustment layer having a refractive index that is smaller than a refractive index of the first semiconductor layer.
2. The light emitting device of claim 1, wherein the refractive index adjustment layer comprises:
a first refractive index adjustment layer arranged on the first semiconductor layer, the first refractive index adjustment layer having a refractive index that is smaller than the refractive index of the first semiconductor layer; and
a second refractive index adjustment layer arranged on the first refractive index adjustment layer, the second refractive index adjustment layer having a refractive index that is smaller than the refractive index of the first refractive index adjustment layer,
wherein the second refractive index adjustment layer comprises a pyramid structure.
3. The light emitting device of claim 2, wherein the first semiconductor layer comprises a nitride-based semiconductor layer, and the first refractive index adjustment layer comprises a ZnO-based semiconductor oxide.
4. The light emitting device of claim 2, wherein the second refractive index adjustment layer comprises a ternary MgO-based compound, or a multicomponent MgO-based compound comprising MgO and at least two other elements.
5. The light emitting device of claim 4, wherein the ternary MgO-based compound comprises MgxBe1-xO, MgxCa1-xO, MgxSr1-xO, or MgxBa1-xO, and
wherein the multicomponent MgO-based compound comprises two or more of Be, Ca, Sr, and Ba.
6. The light emitting device of claim 4, wherein the ternary MgO-based compound or the multicomponent MgO-based compound is doped with an impurity, the impurity comprising at least one of B, In, Zn, TI, Al, Sn, Ga, Te, Si, C, Ge, N, P, As, Sb, Bi, S, Se, Br, I, Ti, and an oxide thereof.
7. The light emitting device of claim 2, wherein the first refractive index adjustment layer comprises at least one of ZnO, Al-doped ZnO, In-doped ZnO, Ga-doped ZnO, ZrO2, TiO2, SiO2, SiO, Al2O3, CuOx, and indium tin oxide (ITO).
8. The light emitting device of claim 1, wherein the first semiconductor layer comprises an n-type semiconductor layer.
9. The light emitting device of claim 1, further comprising a transparent ohmic electrode layer arranged on the first semiconductor layer,
wherein the refractive index adjustment layer is arranged on the transparent ohmic electrode layer.
10. A method for fabricating a light emitting device, the method comprising:
forming a semiconductor stack structure comprising a first semiconductor layer, a second semiconductor layer, and an active layer disposed therebetween, on a substrate; and
forming a refractive index adjustment layer on the first semiconductor layer,
wherein the refractive index of the refractive index adjustment layer is smaller than the refractive index of the first semiconductor layer.
11. The method of claim 10, wherein the refractive index adjustment layer comprises:
a first refractive index adjustment layer formed on the first semiconductor layer, the first refractive index adjustment layer comprising a refractive index smaller than the refractive index of the first semiconductor layer; and
a second refractive index adjustment layer formed on the first refractive index adjustment layer, the first refractive index adjustment layer comprising a refractive index smaller than the refractive index of the first refractive index adjustment layer,
wherein the second refractive index adjustment layer comprises a pyramid structure.
12. The method of claim 10, wherein the substrate is conductive.
13. The method of claim 10, wherein the first semiconductor layer comprises a nitride-based semiconductor layer, and the first refractive index adjustment layer comprises a ZnO-based semiconductor oxide.
14. The method of claim 10, wherein the second refractive index adjustment layer comprises a ternary MgO-based compound, or a multicomponent MgO-based compound comprising MgO and at least two other elements.
15. The method of claim 14, wherein the ternary MgO-based compound comprises MgxBe1-xO, MgxCa1-xO, MgxSr1-xO, or MgxBa1-xO, and
wherein the multicomponent MgO-based compound comprises two or more of Be, Ca, Sr, and Ba.
16. The method of claim 14, wherein the ternary MgO-based compound or the multicomponent MgO-based compound is doped with an impurity, the impurity comprising at least one of B, In, Zn, TI, Al, Sn, Ga, Te, Si, C, Ge, N, P, As, Sb, Bi, S, Se, Br, I, Ti, and an oxide thereof.
17. The method of claim 10, wherein the first refractive index adjustment layer comprises at least one of ZnO, Al-doped ZnO, In-doped ZnO, Ga-doped ZnO, ZrO2, TiO2, SiO2, SiO, Al2O3, CuOx, and indium tin oxide (ITO).