JP2008060530A - White light emitting device - Google Patents

Abstract

A white light emitting device having excellent color stability even under different operating currents is provided.
A white light emitting device including a light emitting element, a nitride phosphor, and a nitride oxide phosphor. The light emitting element generates a first color light having a first wavelength region. The nitride phosphor and the nitride oxide phosphor cover the light emitting element, and after the two phosphors receive and excite the first color light, the second color light having the second wavelength region and the third color light Third color lights having wavelength regions are respectively generated. The first color light, the second color light, and the third color light are mixed to form white light. White light emitting diodes are also disclosed herein.
[Selection] Figure 1

Description

  The present invention relates to a light emitting device, and more particularly to a white light emitting device.

  White light-emitting diodes have advantages such as power saving, low drive voltage, long life, and environmental friendliness, so they are gradually used on the backlights of various lighting devices and liquid crystal displays, It has become an important modern light-emitting device.

  At present, as a manufacturing method of a conventional white light emitting diode, there is a method in which a yellow phosphor material is further added using a blue light emitting element in order to generate white light. The efficiency of the white light generated by this method is quite excellent, but it has the disadvantages that the color rendering properties are poor, the color saturation is poor, and the chromaticity coordinate shift expressed is large under a high current. In the use of a liquid crystal display and a part of lighting equipment, the demand for color is quite severe, and the display and lighting effect of the liquid crystal display and the lighting equipment is reduced due to the above-described defects. Therefore, a white light emitting device having good color stability even under different operating currents and having excellent color rendering and color saturation is required in the modern industry.

  Accordingly, the present invention provides a white light emitting device having excellent color stability even under different operating currents.

  According to an embodiment of the present invention, a white light emitting device including a light emitting device, a nitride phosphor, and a nitrided oxide phosphor is provided. The light emitting element generates first color light having a first wavelength region. The nitride phosphor and the nitride oxide phosphor cover the light emitting element, and after the two phosphors receive and excite the first color light, the second color light and the third wavelength having the second wavelength region are applied. Third color lights having regions are respectively generated. White light is generated by the first color light, the second color light, and the third color light.

  According to one embodiment of the present invention, a white light emitting diode is provided. The white light emitting diode includes a light emitting element, a nitride phosphor, and a nitride oxide phosphor. The light emitting element generates blue light having a first wavelength region. Nitride phosphors are nitride phosphors and nitride oxide phosphors cover this light emitting device, and these two phosphors are nitrides activated by cerium metal and nitride oxides activated by europium metal, respectively. Consists of. The two phosphors receive blue light and are excited to generate red light having a second wavelength region and green light having a third wavelength region, respectively. The blue light, red light and green light are mixed to form white light.

  As described in the embodiments of the present invention, the white light emitting device described in the embodiments of the present invention does not cause a color deviation due to a change in the operating current under different operating currents. In addition, the white light emitting device has a color rendering index (CRI) of 90 or more, and has excellent color rendering properties. In addition, in the embodiment of the present invention, when a white light emitting device combining three primary colors is used and used as a backlight of a display, the color saturation reaches 68%, and a conventional blue chip has a yellow color. This is higher than the color saturation in a backlight display manufactured by combining phosphors.

  FIG. 1 is a sectional structural view of a white light emitting device described in an embodiment of the present invention. In FIG. 1, the white light emitting device 100 is mainly composed of a light emitting element 104 and a sealing resin body 108. The sealing resin body 108 disperses nitride phosphors and nitride oxide phosphors therein, and these two phosphors are composed of nitride and nitride oxide. A sealing tray 102 is provided below the light emitting element 104. At least one lead wire 106 that electrically connects the sealing tray 102 and the light emitting element 104 is provided between the sealing tray 102 and the light emitting element 104, and the light emitting element 104 is externally connected via the lead wire 106. Emits light upon receiving an applied voltage.

  In the embodiment, the light emitting element generates the first color light having the first wavelength region. The first color light excites the nitride phosphor and the nitride oxide phosphor to generate second color light having a second wavelength region and third color light having a third wavelength region, respectively. The white light emitting device 100 further generates white light by mixing the first, second, and third color lights. In one embodiment, the white light emitting device 100 is a white light emitting diode.

  The first color light described above is blue light, and the first wavelength region is about 360 nm to 480 nm. The second color light is red light, and the second wavelength region is about 560 nm to 760 nm. The third color light is green light, and the third wavelength region is about 490 to 660 nm.

The semiconductor element can be the above-described light emitting element, and this semiconductor element is a multi-element composite compound of III-V group elements. The nitride phosphor is, for example, a nitride activated by cerium metal. For example, Ca _x Si _y N ₃ : Ce (0 <(x, y) <4) or CaSiN ₂ : Ce (excitation wavelength is about 300 nm to 500 nm). Nitric oxide phosphor is a nitroxide of europium metal is activated for example, for example, _{Sr 2-2x SiO 4-y N y} : Eu (0 <x <1,0 <y4) or SrSi ₂ O ₂ N ₂ : Eu (excitation wavelength is about 350 nm to 480 nm).

FIG. 2 is an emission light spectrum of each color light under a 20 mA DC operating current of the white light emitting device described in one embodiment of the present invention. Among these, (a) figure is an optical spectrum of the blue light which the semiconductor light-emitting device which consists of a III-V group element radiate | emits, The emission wavelength is about 430 nm-480 nm. (B) The figure shows a light spectrum emitted after the above-described oxynitride phosphor SrSi ₂ O ₂ N ₂ : Eu is excited by receiving blue light, and its emission wavelength is about 480 nm to 660 nm, which is green. It is the optical spectrum of light. The light spectrum that appears between 430 nm and 480 nm is the light spectrum of the outgoing blue light that excites the light source. (C) is a light spectrum emitted after the nitride phosphor CaSiN ₂ : Ce is excited by receiving blue light, and its emission wavelength is 560 nm to 780 nm, which is a light spectrum of red light. (B) As described in the figure, the light spectrum appearing at 430 nm to 480 nm is the light spectrum of the outgoing blue light that excites the light source. (D) The figure shows the light spectrum of white light formed by mixing the light spectrums of the three kinds of colors described above, and the emission wavelength thereof is about 430 nm to 780 nm.

  FIG. 3 shows changes in chromaticity coordinates under different operating currents of the white light emitting device described in FIG. a, b, c, and d represent the white light generated after mixing the blue light, green light, red light, and the three primary colors before light mixing emitted from the white light emitting device. Under different operating currents, the change in the chromaticity coordinates of the light of each color is quite gradual, and as you can see, this white light emitting device has excellent color stability, and its chromaticity coordinates are There is no significant shift with changes in operating current.

  Furthermore, changes in color stability of white light under different operating currents of the white light emitting device described in FIG. 2 are disclosed in [Table 1]. In [Table 1], when the current increases from 5 mA to 60 mA, the chromaticity coordinates, color temperature, and color rendering index (CRI) all show a fairly stable expression. For example, the change in color rendering index is only about 2.1%, and the change in color temperature is less than 1.5%.

  As can be understood from the above embodiment of the present invention, the white light emitting device described in the embodiment of the present invention has excellent stability in chromaticity coordinates, color temperature, and color rendering index under different operating currents. It has. In other words, even if it is necessary to use the white light emitting device under a different operating current, the light emitting device does not cause a color deviation due to a change in the operating current. In addition, the color rendering index (CRI) of the white light emitting device is 90 or more, while the CRI of the conventional white light emitting diode is only about 80. The white light emitting device in the embodiment of the invention has a better color rendering. In addition, in the embodiment of the present invention, when a white light emitting device combining three primary colors is used and used as a display backlight, the color saturation reaches 68%, and the conventional blue chip has a yellow fluorescent color. It is 13% higher than the color saturation (about 60%) in the backlight display manufactured by combining the bodies.

  The present invention has been disclosed in the present invention as described above, but this is not intended to limit the present invention. Various modifications can be made by those skilled in the art without departing from the spirit and scope of the present invention. And the scope of protection of the present invention shall be regarded as limited by the scope of the appended claims.

In order that the above and other objects, features, advantages and embodiments of the present invention may be more clearly understood, the following detailed description of the accompanying drawings is presented as follows.
It is a cross-section figure of the white light-emitting device described in one Example of this invention. It is an emitted light spectrum of each color light under a 20 mA DC operating current of the white light emitting device described in one embodiment of the present invention. 3 is a change in each chromaticity coordinate under different operating currents of the white light emitting device described in FIG. 2.

Explanation of symbols

100 white light emitting device 102 sealing tray 104 light emitting element 106 lead wire 108 sealing resin body

Claims (10)

A light emitting element for generating a first color light having a first wavelength region;
A nitride phosphor that coats the light emitting element and generates the second color light having a second wavelength region after receiving and exciting the first color light;
A nitride oxide phosphor that coats the light emitting element and generates the third color light having a third wavelength region after being excited by receiving the first color light;
The white light emitting device, wherein the third color light, the second color light, and the first color light are mixed to form white light.   The white light-emitting device according to claim 1, wherein the light-emitting element is a semiconductor element of a multi-element composite compound of a group III-V element.   The white light emitting device according to claim 1, wherein the first wavelength region is about 360 nm to 480 nm.   The white light emitting device according to claim 1, wherein the second wavelength region is about 560 nm to 760 nm. _2. The white light emitting device according to claim 1, wherein a chemical formula of the nitride phosphor is CaSiN ₂ : Ce. 2. The white light emitting device according to claim 1, wherein a chemical formula of the nitride phosphor is Ca _x Si _y N ₃ : Ce and 0 <(x, y) <4.   The white light emitting device according to claim 1, wherein the third wavelength region is about 490 to 660 nm. _2. The white light emitting device according to claim 1, wherein a chemical formula of the nitrided oxide phosphor is SrSi ₂ O ₂ N ₂ : Eu. 2. The white light according to claim 1, wherein a chemical formula of the nitrided oxide phosphor is Sr _2-2x SiO _{4 -y} N _y : Eu and 0 <x <1, 0 <y4. Light emitting device. A light emitting element for generating blue light having a first wavelength region;
A nitride phosphor that is a nitride activated by cerium metal that covers the light-emitting element and is excited by receiving and exciting the blue light and generating red light having a second wavelength region;
A nitric oxide phosphor that is a nitric oxide activated by europium metal that coats the light emitting element and is excited by receiving the blue light and then generating green light having a third wavelength region;
The white light emitting diode, wherein the green light, the red light, and the blue light are mixed to form white light.

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