Semiconductor luminous element with light reflection and focusing configuration

DETAILED DESCRIPTION OF THE INVENTION FIG.
1 (a) shows a cross section of semiconductor luminous element A, a surface-emitting element which is a first preferred embodiment of this invention.
Luminous element A consists of semiconductor substrate 2, on which is fashioned multilayer reflective film 3, which is a laminate with a number of layers of thin film with different refractive indices; lower cladding layer 4; active layer 5, which emits light; upper cladding layer 6; and cap layer 7.
All of these layers are stacked one atop the next starting with substrate 2.
On top of cap layer 7 is reflecting lens layer 8, which is formed from an insulating material.
Surface electrode 11 is provided on top of lens layer 8 to conduct the current.
Surface electrode 1 is formed on the lower surface of semiconductor substrate 2.
Window 12 is provided in surface electrode 11 to allow the light to escape.
On its edges, surface electrode 11 comes in contact with the upper surface of cap layer 7.
The aforesaid lens layer 8 is divided into concentric bands 8a, 8b, .
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, as shown in FIG.
1 (b) (or only a portion of the bands shown), with the center left open, so that window 12 can be aligned with opening 13 in the center of reflecting lens layer 8.
To the upper surface of each concentric band 8a, 8b, .
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is attached a reflective film 9, preferably provided by depositing a metal with high reflectivity.
Optically reflective surfaces 10 (reverse-surface mirrors) are formed on the upper surfaces of reflecting lens layer 8.
The optically reflective surface 10 of each concentric band 8a, 8b, .
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is at an oblique angle with respect to the surface of semiconductor substrate 2.
Each reflective surface 10 on a concentric band 8 is set at a different pitch, so that each surface 10 reflects the light toward the center of reflecting lens layer 8 (i.
e.
, toward window 12).
Although the details are not shown in the drawing, multilayer reflective film 3 generally consists of two materials with different refractive indices which are stacked alternately at a thickness