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US 5,294,815 AGranted
Semiconductor light emitting device with terraced structure
AssigneesRicoh Company, Ltd., Ricoh Research Institute of General Electronics Co., Ltd.
InventorHiroyuki Iechi
Life of this patent
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Abstract
A semiconductor light emitting device able to emit a high intensity, stable light. An edge surface lighting type light emitting diode array is formed on a substrate. A light emitting edge surface of each light emitting element is formed by an etching method. A surface of the substrate in front of the light emitting edge surface is formed in multiple stage so that a light beam is not reflected by the surface of the substrate.
Claims4
A semiconductor light emitting device which comprises:
- a substrate on which a light emitting diode is formed;
- said light emitting diode having at least a light emitting layer and electrodes positioned on both sides of the light emitting layer, and having a light emitting edge surface perpendicular to a plane of the light emitting layer;
- and
- a plurality of grooves separating said light emitting diode into a plurality of light emitting diode elements;
- said substrate including a first surface parallel to a center axis of a light beam emitted from said light emitting diode element, a second surface having a step and formed to be parallel to said first surface, a first terrace edge formed between the first and second surfaces, and a second terrace edge formed on the edge of said substrate;
- said first and second surfaces are formed so as to satisfy the following two equations;
- Lx.sub.1 <Lz.sub.1 /tan .theta.
- Lx.sub.2 <Lz.sub.2 /tan .theta.
- where:
- Lx.sub.1 is a distance between said light emitting edge surface and said first terrace edge;
- Lx.sub.2 is a distance between said light emitting edge surface and said second terrace edge;
- Lz.sub.1 is a distance between said light emitting layer and said first surface;
- Lz.sub.2 is a distance between said light emitting layer and said second surface;
- .theta. is a diverging angle of the light beam emitted from said light emitting diode elements from the center axis towards the surface of said substrate.
11 more elements
A semiconductor light emitting device which comprises:
- a substrate on which a light emitting diode is formed;
- a light emitting diode comprising a layered structure formed on said substrate, having at least a light emitting layer and electrodes positioned on both sides of the light emitting layer, and having a light emitting edge surface formed to be perpendicular to a plane of the light emitting layer;
- and
- a plurality of grooves separating said light emitting diode into a plurality of light emitting diode elements;
- said substrate including a plurality of surfaces, one to m, formed to be parallel to a center axis of a light beam, the surfaces being formed so as to have a step between the surfaces, and a plurality of terrace edges, one to m, formed between the surfaces;
- an n-th surface is formed so as to satisfy the following equation;
- LX.sub.n <Lz.sub.n /tan 0
- where:
- n is an integer from 1 to m;
- Lx.sub.n is a distance between said light emitting edge surface and the n-th terrace edge;
- Lz.sub.n is a distance between said light emitting layer and the n-th surface;
- .theta. is a diverging angle of the light beam emitted from said light emitting diode elements, from the center axis towards the surface of said substrate.
9 more elements
Dependencies are inferred from the claim text.