Light-emitting devices with high extraction efficiency
First Claim
1. A light-emitting device, comprising:
- a light-emitting portion, including;
a substrate which is optically transparent;
a light-emitting layer which is sandwiched by a p-type cladding layer and an n-type cladding layer and is optically transparent;
said p-type cladding layer which locates on one side of said light-emitting layer and is optically transparent;
said n-type cladding layer which locates on the other side of said light-emitting layer and is optically transparent;
a p-type electrode layer located on said p-type cladding layer; and
an n-type electrode layer located on said n-type cladding layer, characterized in that said light-emitting device comprising;
a light control portion, comprising;
a light-tunneling layer which is disposed on a light-exiting surface of said light-emitting device and has a refractive index lower than refractive indices of said substrate, said cladding layers and said electrode layers to the wavelength of the major emitted light emitted by said light-emitting layer and has a thickness smaller than the wavelength of the major emitted light.
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Abstract
The present invention relates to a light-emitting device having a substrate and a light-emitting layer comprising an electroluminescent material, wherein the light-emitting layer (p-n junction) is sandwiched between a p-type cladding layer with a p-electrode layer and an n-type cladding layer with an n-electrode layer. The light-emitting device is characterized in that a light control portion is deposited on a light-exiting surface of the light-emitting device. Said light control portion comprises at least one light-tunneling layer. Said light-tunneling layer has a refractive index with respect to the wavelength of the main emitting-light from the light-emitting layer lower than the refractive indices of the substrate, the cladding layers and the electrode layers. The light extraction efficiency is increased by the light tunneling effect when the emitting-light emitted by the light-emitting layer enters the interface between the epitaxial layer and the surrounding material with an incident angle larger than the critical angle. The tunneling light from the light control portion can be polarized, such that a polarized light-emitting device can be realized in practice.
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Citations
18 Claims
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1. A light-emitting device, comprising:
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a light-emitting portion, including;
a substrate which is optically transparent;
a light-emitting layer which is sandwiched by a p-type cladding layer and an n-type cladding layer and is optically transparent;
said p-type cladding layer which locates on one side of said light-emitting layer and is optically transparent;
said n-type cladding layer which locates on the other side of said light-emitting layer and is optically transparent;
a p-type electrode layer located on said p-type cladding layer; and
an n-type electrode layer located on said n-type cladding layer, characterized in that said light-emitting device comprising;
a light control portion, comprising;
a light-tunneling layer which is disposed on a light-exiting surface of said light-emitting device and has a refractive index lower than refractive indices of said substrate, said cladding layers and said electrode layers to the wavelength of the major emitted light emitted by said light-emitting layer and has a thickness smaller than the wavelength of the major emitted light. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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Specification