1. A spark plug comprising:
a center electrode extending in an axial direction of said spark plug;
a substantially cylindrical insulator disposed on an outer circumference of said center electrode;
a cylindrical metal shell disposed around said insulator; and
a ground electrode including a bent portion bent at an intermediate portion of said ground electrode so that a rear end portion of said ground electrode is bonded to a leading end portion of said metal shell and a leading end portion of said ground electrode is opposed to a leading end face of said center electrode,
wherein a spark discharge gap is provided between the leading end portion of said center electrode and the leading end portion of said ground electrode, and
said ground electrode has a bulging curved face on a side opposite to a side in which said center electrode is provided, and a maximum of width of said ground electrode within a range of \xb11 mm from a center point of said spark discharge gap in the axial direction, as viewed in a direction where said center electrode and said ground electrode overlap, is 105% or less of a width of an ordinary portion having a substantially constant width.
2. The spark plug as claimed in claim 1, wherein said maximum of width of said ground electrode is 101% or more of said width of said ordinary portion.
3. The spark plug for as claimed in claim 1, wherein a ratio of a thickness of said ground electrode to said width of said ordinary portion is 0.5 is more.
4. The spark plug for as claimed in claim 2, wherein a ratio of a thickness of said ground electrode to said width of said ordinary portion is 0.5 is more.
5. The spark plug as claimed in claim 1, wherein a Vickers hardness of a portion of said ground electrode having said maximum of width is from 140% to 170% of a Vickers hardness of said ordinary portion.
6. The spark plug as claimed in claim 2, wherein a Vickers hardness of a portion of said ground electrode having said maximum of width is from 140% to 170% of a Vickers hardness of said ordinary portion.
7. The spark plug as claimed in claim 3, wherein a Vickers hardness of a portion of said ground electrode having said maximum of width is from 140% to 170% of a Vickers hardness of said.ordinary portion.
8. The spark plug as claimed in claim 4, wherein a Vickers hardness of a portion of said ground electrode having said maximum of width is from 140% to 170% of a Vickers hardness of said ordinary portion.
9. The spark plug as claimed in claim 1, wherein said curved face of said ordinary portion of said ground electrode has a radius of curvature of from 0.5 mm to 1.3 mm.
10. The spark plug as claimed in claim 2, wherein said curved face of said ordinary portion of said ground electrode has a radius of curvature of from 0.5 mm to 1.3 mm.
11. The spark plug as claimed in claim 3, wherein said curved face of said ordinary portion of said ground electrode has a radius of curvature of from 0.5 mm to 1.3 mm.
12. The spark plug as claimed in claim 4, wherein said curved face of said ordinary portion of said ground electrode has a radius of curvature of from 0.5 mm to 1.3 mm.
13. The spark plug as claimed in claim 5, wherein said curved face of said ordinary portion of said ground electrode has a radius of curvature of from 0.5 mm to 1.3 mm.
14. The spark plug as claimed in claim 6, wherein said curved face of said ordinary portion of said ground electrode has a radius of curvature of from 0.5 mm to 1.3 mm.
15. The spark plug as claimed in claim 7, wherein said curved face of said ordinary portion of said ground electrode has a radius of curvature of from 0.5 mm to 1.3 mm.
16. The spark plug as claimed in claim 8, wherein said curved face of said ordinary portion of said ground electrode has a radius of curvature of from 0.5 mm to 1.3 mm.
17. The spark plug as claimed in claim 1, wherein said ground electrode includes an outer layer and an inner layer made from a metal having a higher thermal conductivity than that of said outer layer, and a ratio, as taken in a section of said ordinary portion, of a sectional area of said inner layer to an sectional area of said ordinary portion is from 25% to 60%.
18. The spark plug as claimed in claim 2, wherein said ground electrode includes an outer layer and an inner layer made from a metal having a higher thermal conductivity than that of said outer layer, and a ratio, as taken in a section of said ordinary portion, of a sectional area of said inner layer to an sectional area of said ordinary portion is from 25% to 60%.
19. The spark plug as claimed in claim 1, wherein said ground electrode has at least one bent portion at outside of said range of \xb11 mm from the center point of said spark discharge gap in said axial direction.
20. The spark plug as claimed in claim 2, wherein said ground electrode has at least one bent portion at outside of said range of \xb11 mm from the center point of said spark discharge gap in said axial direction.
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 chip, comprising:
a light emitting unit;
a eutectic layer, having a first surface and a second surface opposite to each other, wherein the light emitting unit connects to the first surface of the eutectic layer; and
a surface passivation layer, covering the second surface of the eutectic layer, wherein a material of the surface passivation layer comprises at least a metal of an oxidation potential from \u22120.2 volts to \u22121.8 volts.
2. The light emitting chip as claimed in claim 1, wherein a material of the surface passivation layer is selected from the group consisting gold, platinum, gold alloy, platinum alloy, and a combination thereof.
3. The light emitting chip as claimed in claim 1, wherein a material of the surface passivation layer is gold having a purity level larger than 99.9 wt %.
4. The light emitting chip as claimed in claim 1, wherein a thickness of the surface passivation layer ranges from 1 nm to 1000 nm.
5. The light emitting chip as claimed in claim 4, wherein a thickness of the surface passivation layer ranges from 5 nm to 100 nm.
6. The light emitting chip as claimed in claim 1, wherein a ratio of a thickness of the eutectic layer to a thickness of the surface passivation layer ranges from 10 to 10000.
7. The light emitting chip as claimed in claim 1, wherein a material of the eutectic layer is a eutectic alloy consisting at least two materials selected from tin, indium, silver, and bismuth.
8. The light emitting chip as claimed in claim 1, wherein the light emitting unit comprises:
a semiconductor epitaxial layer, comprising a first type semiconductor layer, a light emitting layer and a second type semiconductor layer;
a first electrode, disposed on the first type semiconductor layer, and electrically connected with the first type semiconductor layer; and
a second electrode, disposed on the second type semiconductor layer, and electrically connected with the second type semiconductor layer.
9. The light emitting chip as claimed in claim 8, wherein the eutectic layer directly covers a first upper surface of the first electrode and a second upper surface of the second electrode.
10. The light emitting chip as claimed in claim 9, wherein the light emitting unit further comprises:
a substrate, wherein the semiconductor epitaxial layer is disposed on an upper surface of the substrate;
an insulating layer, disposed between the first electrode and the semiconductor epitaxial layer and between the second electrode and the second type semiconductor layer, wherein a portion of the insulating layer is exposed between the first electrode and the second electrode; and
a conductive structure layer, disposed between the second type semiconductor layer and the insulating layer, wherein the second electrode is electrically connected to the conductive structure layer.
11. The light emitting chip as claimed in claim 10, wherein a material of the conductive structure layer is selected from the group consisting indium tin oxide, aluminum doped zinc oxide, indium zinc oxide, and a combination thereof.
12. The light emitting chip as claimed in claim 8, wherein the light emitting unit further comprises:
a substrate, having an upper surface and a lower surface opposite to each other, wherein the semiconductor epitaxial layer is disposed on the upper surface, and the eutectic layer covers the lower surface.
13. The light emitting chip as claimed in claim 8, wherein the eutectic layer covers a surface of the first electrode relatively away from the first type semiconductor layer.
14. The light emitting chip as claimed in claim 1, wherein an oxidation potential of the eutectic layer is larger than an oxidation potential of the surface passivation layer.