Light emitting diode

1. A light emitting diode of a double hetero-junction type in which a light-emitting layer made of a GaAlInP material is interposed between a p-type cladding layer and an n-type cladding layer, wherein:

a p-side electrode is formed on a p-type cladding layer-side surface having an area of 0.15 mm thus or more;

any point present in a region not containing the p-side electrode of said p-type cladding layer-side surface is within a distance of (Ld×2) from some point on an edge of said p-side electrode, where Ld is a distance from a position at which an optical power is maximum, to a position at which the optical power attenuates by 90%; and

said p-side electrode comprises a plurality of branch electrodes and a connection electrode connecting said branch electrodes to each other electrically.

2. A light emitting diode according to claim 1 , wherein an interval between said branch electrodes is approximately Ld.

3. A light emitting diode according to claim 2 , wherein said surface on which the p-side electrode is formed has two opposed parallel straight sides; and

said branch electrodes are each strip-shaped, and arranged parallel with said two sides- and with each other.

4. A light emitting diode according to claim 3 , wherein an interval between an outermost branch electrode and the side of said surface opposed to this branch electrode is approximately Ld/2.

5. A light emitting diode according to claim 1 , comprising a current diffusion layer made of a AIGaInP material and disposed between said p-type cladding layer and said p-side electrode.

6. A light emitting diode according to claim 1 , comprising a barrier layer between said light-emitting layer and said p-type cladding layer, said barrier layer having a band gap intermediate between band gaps of said light-emitting layer and p-type cladding layer.

7. A light emitting diode according to claim 6 , further comprising a barrier layer between said light-emitting layer and said n-type cladding layer, said barrier layer having a band gap intermediate between band gaps of said light-emitting layer and said n-type cladding layer.

8. A light emitting diode of a double hetero-junction type in which a light-emitting layer made of a GaAlInP material is interposed between a p-type cladding layer and an n-type cladding layer comprising:

a current blocking layer formed on a p-type cladding layer-side surface having an area of 0.15 mm 2 or more; and

a p-side electrode formed at a position above said current blocking layer and opposed to said current blocking layer,

wherein any point present in a region not containing the current blocking layer of said p-type cladding layer-side surface is within a distance of (Ld×2) from some point on an edge of said current blocking layer, where Ld is a distance from a position at which an optical power is maximum, to a position at which the optical power attenuates by 90%; and

said current blocking layer comprises a plurality of blocking branch portions and a connection portion connecting said blocking branch portions to each other electrically, and an interval between adjacent blocking branch portions is approximately Ld.

9. A light emitting diode according to claim 8 , wherein the surface on which said current blocking layer is formed has two opposed parallel straight sides; and

said blocking branch portions are each strip-shaped and arranged parallel with said two sides and with each other.

10. A light emitting diode according to claim 9 , wherein an interval between an outermost blocking branch portion and the side of said surface opposed to this outermost blocking branch portion is approximately Ld/2.

11. A light emitting diode according to claim 8 , comprising a current diffusion layer made of an AlGaInP material and disposed between said p-type cladding layer and said p-side electrode.

12. A light emitting diode according to claim 8 , comprising a barrier layer between said light-emitting layer and said p-type cladding layer, said barrier layer having a band gap intermediate between band gaps of said light-emitting layer and p-type cladding layer.

13. A light emitting diode according to claim 12 , further comprising a barrier layer between said light-emitting layer and said n-type cladding layer, said barrier layer having a band gap intermediate between band gaps of said light-emitting layer and said n-type cladding layer.

14. A light emitting diode of a double hetero-junction type in which a light-emitting layer made of a GaAlInP material is interposed between a p-type cladding layer and an n-type cladding layer, wherein:

a p-side electrode is formed on a p-type cladding layer-side surface, said p-side electrode consisting of a plurality of mutually connected constituent parts; and

any point present in a region not containing the p-side electrode of said p-type cladding layer-side surface is within a distance of (Ld×2) from some point on an edge of said p-side electrode, where Ld is a distance from a position at which an optical power is maximum, to a position at which the optical power attenuates by 90%.

15. A light emitting diode according to claim 14 , wherein said p-type cladding layer-side surface is a surface of a current diffusion layer.

16. A light emitting diode according to claim 15 , wherein the current blocking layer having a shape corresponding to that of said p-side electrode is formed inside said current diffusion layer in a position opposed to said p-side electrode.