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Light emitting device with fluorescent material

A fluorescent substance and ultraviolet light technology, applied in semiconductor devices, electrical components, circuits, etc., can solve problems such as shortening the light emission wavelength, difficulty in high-efficiency and high-color reproduction light-emitting devices, and low light emission efficiency of red fluorescent substances

Inactive Publication Date: 2009-03-18
KK TOSHIBA
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  • Claims
  • Application Information

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Problems solved by technology

However, in the case of shortening the light emission wavelength, it is considered that sufficient efficiency cannot be obtained due to the absorption of light by, for example, GaN formed on a sapphire substrate or the like.
[0006] As described above, in the case of exciting a red fluorescent substance with a light emitting diode formed of a semiconductor such as GaN and its mixed crystal, etc., the light emission efficiency of the red fluorescent substance is low
It is considered that even if the light emission wavelength is shortened in order to increase light emission efficiency, sufficient efficiency cannot be obtained due to light absorption by semiconductors such as GaN, etc.
Therefore, by using a light emitting diode formed of a semiconductor such as GaN and its mixed crystal, etc., the red fluorescent substance cannot be made to emit light efficiently
In addition, it is difficult to realize a light-emitting device with high efficiency and high color reproduction by combining red phosphors with any other visible light phosphors

Method used

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  • Light emitting device with fluorescent material
  • Light emitting device with fluorescent material
  • Light emitting device with fluorescent material

Examples

Experimental program
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Effect test

no. 1 example

[0022] Such as figure 1 As shown in , the light emitting device according to this embodiment is a light emitting diode formed of a GaN-based compound semiconductor formed on a sapphire substrate. That is, on a substrate 1 whose surface is a sapphire c-plane, a first AlN buffer layer 2 having a high carbon concentration (carbon concentration: 3×10 18 up to 5×10 20 / cm 3 , film thickness: 3 to 20nm), high-purity second AlN buffer layer 3 (carbon concentration: 1×10 18 to 3×10 18 / cm 3 , film thickness: 2 μm), non-doped GaN buffer layer 4 (film thickness: 3 μm), Si-doped n-type GaN contact layer 5 (Si concentration: 1×10 18 up to 5×10 18 / cm 3 , film thickness: 2 to 5 μm).

[0023] In addition, on the Si-doped n-type GaN contact layer 5, Si-doped n-type Al 0.05 Ga 0.95 N first confinement layer 6 (Si concentration: 1×10 18 / cm 3 , film thickness: 20nm), Si-doped n-type GaN first absorption layer 7 (Si concentration: 1×10 18 / cm 3 , film thickness: 100nm), Si-doped n...

no. 2 example

[0050] Figure 4 is a sectional view showing the structure of a light emitting device according to a second embodiment of the present invention. Like reference numerals denote equivalents to figure 1 parts of those parts. As shown in the figure, the light emitting device according to the present embodiment is obtained by combining the fluorescent substance with the light emitting device according to the first embodiment figure 1 The light-emitting diodes shown in combine the obtained white LEDs. That is, if Figure 4 As shown in , the reflective film 32 is provided on the inner surface of the package 31 formed of ceramics or the like, and the reflective film 32 is separately provided on the inner side surface and the bottom surface of the package 31 . The reflective film 32 is formed of, for example, aluminum. Will figure 1 The light emitting diode shown in is mounted on a reflective film 32 provided on the bottom surface of the package 31 .

[0051] The n-side electrod...

no. 3 example

[0061] Figure 5 is a sectional view showing the structure of a light emitting device according to a third embodiment of the present invention. Like reference numerals denote equivalents to figure 1 and 4 parts of those parts. Such as Figure 5 As shown in , the light-emitting device according to this embodiment is also made by combining the fluorescent substance with the light-emitting device according to the first embodiment figure 1 The light-emitting diodes shown in combine the obtained white LEDs. The difference from the second embodiment is that the fluorescent substance area is also disposed under the light emitting diodes.

[0062] Such as Figure 5 As shown in , a fluorescent substance region 41 containing blue, green or yellow fluorescent substances is formed on the reflective film 32 on the bottom surface of the package 31, and mounted and fixed on the fluorescent substance region 41figure 1 LEDs shown in . Bonding with an adhesive, welding, or the like may b...

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Abstract

A light emitting device includes a transparent substrate (1) having first and second surfaces, a semiconductor layer (2-6) provided on the first surface, a first light emission layer (11) provided over the semiconductor layer (2-6) and emitting first ultraviolet light including a wavelength corresponding to an energy larger than a forbidden bandwidth of a semiconductor of the semiconductor layer, a second light emission layer (8) provided between the first light emission layer (11) and the semiconductor layer (2-6), absorbing the first ultraviolet light emitted from the first light emission layer (11), and emitting second ultraviolet light including a wavelength corresponding to an energy smaller than the forbidden bandwidth of the semiconductor of the semiconductor layer (2-6), and first (18) and second (19) electrodes provided to apply electric power to the first light emission layer (11).

Description

technical field [0001] The present invention relates to a light emitting device using a nitride-based III-V compound semiconductor or a light emitting device using a fluorescent substance. Background technique [0002] By utilizing light-emitting diodes (LEDs) formed of GaN and its mixed crystals, attempts have been made to obtain white light based on the emission of various types of light with different peak wavelengths, replacing conventional white fluorescent lamps (see, for example: Japanese Patent Application Laid-Open Publication No. 2001-352098). In this publication, a Si-doped GaN light-excitation emissive layer is excited by blue light generated in a multiple quantum well (MQW) light-emitting layer of a light-emitting diode to generate yellow light, and using the fact that these lights have a complementary color relationship, by This gives white light. However, red cannot be generated in the light emitting device described in the above publication, thereby deterio...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01L33/00H01L33/08H01L33/32
Inventor 大场康夫
Owner KK TOSHIBA
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