Active solid-state devices (e.g. – transistors – solid-state diode – Incoherent light emitter structure
Reexamination Certificate
2003-04-03
2004-10-26
Prenty, Mark V. (Department: 2822)
Active solid-state devices (e.g., transistors, solid-state diode
Incoherent light emitter structure
C257S098000
Reexamination Certificate
active
06809342
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention concerns a light emitting diode (light-emitting device, hereinafter), and more particularly, a light-emitting device having an object of obtaining different luminous colors by using a wavelength converter for the luminous body from a tip (semiconductor light-emitting element, hereinafter) of the light emitting diode, and a manufacturing method thereof.
2. Detailed Description of the Prior Art
As LED lamp (light-emitting device) using the conventional wavelength converter, a white light-emitting LED, combining an LED tip emitting blue light and a YAG (yttrium, aluminum, garnet)-type phosphor converting blue light into yellow, is known. Moreover, a white light-emitting LED, combining an LED tip emitting ultraviolet light and a white light-emitting phosphor, has been proposed. (Refer to the patent document 1, for example).
Patent Document 1
Japanese Patent Laid-Open No. 1999-242513
However, in the conventional composition of the LED lamp (light-emitting device) described above, even when the phosphor is dispersed evenly in a light-transmittance-sealing-materiel, for instance, making the dispersion uneven and the luminous color irregular, the phosphor precipitates and dispersion of the phosphor gets uneven because of the difference of the specific gravity between the light-transmittance-sealing-materials and phosphor before the light-transmittance-sealing-materials for sealing the transmitting light become hard, which is problematic.
In addition, even if it is possible to disperse the phosphor evenly so as to prevent the color from becoming irregular, given that the additional amount of phosphor is fixed, it is inevitable that the luminous color of the light-emitting device changes from the yellow spectrum to the blue spectrum as an electric current value increases because of the variation in amount of the irradiated blue light and the variation in the electric current value impressed the LED tip (semiconductor light-emitting element), which deteriorates the color reproducibility.
When adopting a semiconductor light-emitting element radiating a light particularly containing much ultraviolet components, in such a composition to make use of the white light obtained by transmitting it through the phosphor, the ratio of the ultraviolet transmitting without any contacts with the phosphor increases, when the amount of annex to the phosphor is low, which, in turn, makes the light-emitting device low in conversion efficiency and dark, and causes a problem of ultraviolet radiation, assumed to be harmful to life, outside the light-emitting element.
Moreover, the capture rate of ultraviolet certainly improves, by increasing the amount of the annex to phosphor. Though it is possible to reduce the amount of ultraviolet radiated outside the light-emitting element, the phosphor itself becomes lower in transparency, thereby lowers the total transmittance as sealing materials and, as a result, provoking an impropriety of being unable to obtain a bright light-emitting device in any way, constituting a problem to be resolved.
SUMMARY OF THE INVENTION
The present invention is to resolve the problems by providing a light-emitting device, which comprises a substrate, a semiconductor light-emitting element mounted on the substrate, and a wavelength converter created by a phosphor releasing a wavelength-converted light, which is different from the fundamental wavelength-light radiated from the aforementioned semiconductor light-emitting element, wherein:
a light-radiation-direction-limiter in the shape of a horn where its inner wall is opening upward on a substantially central portion having a function to limit the direction of the radiation of light from the aforementioned semiconductor light-emitting element, and a reflector around the light-radiation-direction-limiter. The aforementioned wavelength converter is arranged to cover an opening of the aforementioned light-radiation-direction-limiter and not to contact with the limiter's edge. Moreover, the combination of both of the wavelength-converted light transmitted through the aforementioned wavelength converter and radiated in the radiation direction of this light-emitting element, fundamental wavelength-light reflected to the inner face of the wavelength converter, among the light coming out of the aforementioned semiconductor light-emitting element, which reaches the aforementioned wavelength converter, and/or the light reflecting wavelength-converted light to the radiation direction of this light-emitting with the aforementioned reflector, can be taken out as the output light, as a concrete mean to solve the aforementioned problems of the prior art.
REFERENCES:
patent: 5959316 (1999-09-01), Lowery
patent: 6340824 (2002-01-01), Komoto et al.
patent: 6373188 (2002-04-01), Johnson et al.
patent: 2003/0230751 (2003-12-01), Harada
patent: 10-107325 (1998-04-01), None
patent: 10-190065 (1998-07-01), None
patent: 10-190066 (1998-07-01), None
patent: 10-242513 (1998-09-01), None
patent: 2001-127346 (2001-05-01), None
patent: 2001-135861 (2001-05-01), None
patent: 2001-156338 (2001-06-01), None
patent: 2001-177153 (2001-06-01), None
patent: 2001-196639 (2001-07-01), None
patent: 2001-210872 (2001-08-01), None
patent: 2001-217466 (2001-08-01), None
patent: 2001-230451 (2001-08-01), None
patent: 2001-345483 (2001-12-01), None
patent: 2002-57375 (2002-02-01), None
Prenty Mark V.
Stanley Electric Co. Ltd.
Weingarten Schurgin, Gagnebin & Lebovici LLP
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