KR100573488B1 - Light emitting diode - Google Patents

Abstract

The present invention relates to a light emitting device, comprising a light emitting device having a peak emission wavelength in the range of 400 nm to 450 nm, and a molding resin layer surrounding the light emitting device, wherein the molding resin layer has a yellow phosphor and a green color. Family of phosphors. The molding resin layer may further include an orange-based phosphor. Each phosphor is preferably composed of an orthosilicate series activated by rm Eu ^ 2 +. According to this, the reproduction range of the white light is expanded, and thus it is well applicable to various lighting products, in particular, high brightness products, and the luminous efficiency is also improved. Since the color component of the red region is increased, the color rendering property can be improved, and thus the color reproduction ability can be maximized.

Light emitting device, light emitting device, molding resin layer, luminous efficiency, lighting, white light

Description

Light Emitting Device {LIGHT EMITTING DIODE}

1 is a graph showing a light emission spectrum of a conventional light emitting device;

FIG. 2 is a chromaticity diagram for describing emission colors of the light emitting device of FIG. 1; FIG.

3 is a cross-sectional view of a lead type light emitting device according to the present invention;

4 is a cross-sectional view of a chip type light emitting device according to the present invention;

FIG. 5 is a chromaticity diagram for describing light emission colors of a light emitting device according to a first embodiment of the present invention; FIG.

6 is a chromaticity diagram for explaining light emission colors of a light emitting device according to a second embodiment of the present invention;

7 is a graph showing light emission spectra of the light emitting device according to the second embodiment of FIG. 6;

8 is a chromaticity diagram of a light emitting device according to a third embodiment of the present invention;

9 is a chromaticity diagram of a light emitting device according to a fourth embodiment of the present invention; and

10 is a chromaticity diagram of a light emitting device according to a fifth embodiment of the present invention.

<Detailed description of the major symbols in the drawings>

1, 21: light emitting device

7: light emitting element

11: Molding resin layer

13: wire

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

Many efforts have been made to implement white light using light emitting diodes. The method of generating white light can be largely divided into a method using three light emitting elements of R, G, and B, and a method using a single light emitting element.

In the method using three light emitting devices, R (Red, hereinafter referred to as a red series), G (Green, hereinafter referred to as a green series), and B (blue, hereinafter referred to as a blue series) light emitting devices are close to each other. The white light is provided by appropriately adjusting the voltage applied to each device. However, in this method, since the characteristics of each light emitting device are different, it is difficult to realize a satisfactory level of white light, such as color staining due to uneven mixing of light generated in the light emitting device. In particular, there is a problem that the manufacturing price increases because of the complexity of the plurality of light emitting elements and the driving circuits for voltage regulation thereof.

Therefore, recently, a method using a single light emitting device, that is, a light emitting device in which a phosphor is contained in a light emitting device and a resin mold layer covering the same has been disclosed. In the conventional light emitting device, a blue light emitting device is used, and the phosphor contains Y (Yellow, hereinafter, yellow light) phosphor. Then, the phosphor excited by the photons emitted primarily from the light emitting device generates secondary light, and white light is realized by the diffusion mixing of the primary and secondary light.

Fig. 1 shows a light emission spectrum of a light emitting device employing such a scheme graphically. Referring to the drawings, the conventional light emitting device has a light emission peak wavelength around a (460 nm to 470 nm). At this time, the peak emission wavelength of the phosphor excited by the light emitting element is formed near b (570 nm). As a result, the color reproduction range by the conventional light emitting device can be represented by a hatched portion on the chromaticity diagram of FIG. 2, and the reproduction range of the white light is represented by the W portion which is the center region.

By the way, in the conventional light emitting device, as can be seen in Fig. 2, the reproducible color range (refer to the hatched portion) is very narrow, and furthermore, the reproduction range of the white light is limited within the narrow color range. There is a problem that the applicability is low and the luminous efficiency is lowered. Therefore, there is a limit to use as a general-purpose product for lighting, and in particular, it is difficult to apply to high-brightness products. In addition, when such a conventional light emitting device is used for a backlight, there is also a problem such as deterioration of color reproduction ability.

In the conventional light emitting device, with reference to Fig. 1, there is a problem in that color rendering is deteriorated because there is almost no color component having a red region, that is, a wavelength in the range of 650 nm to 700 nm. This problem is also a factor limiting the applicability for color reproduction.

 In view of the above problems, the present invention expands the reproduction range of white light, that is, broadly expands the reproduction range of the conventionally limited white light on a chromaticity drawing, so that it can be suitably applied to various lighting products, particularly high brightness products. It is to provide a light emitting device.

Another object of the present invention is to provide a light emitting device that can be utilized in various lighting products and, in particular, maximize color reproduction ability by increasing color components of a red region to improve color rendering properties.

Another object of the present invention is to provide a light emitting device having increased luminous efficiency.

According to the present invention, the object includes a light emitting device having a peak emission wavelength in the range of 400nm to 450nm, and a molding resin layer surrounding the light emitting device, wherein the molding resin layer is a yellow phosphor and green A light emitting device including a color-based phosphor is achieved.

The amount of the yellow-based and green-based phosphors may be selected within the range of 70:30 to 99: 1.

The molding resin layer may further include an orange-based phosphor, and in this case, the amount of the yellow-based, green-based and orange-based phosphors included in the molding resin layer is 70:20:10 to 95: 4: It can be selected within the range of 1.

On the other hand, the object of the present invention includes a light emitting device having a peak emission wavelength in the range of 400 nm to 450 nm, and a molding resin layer surrounding the light emitting device, wherein the molding resin layer is a green-based phosphor and an orange-based phosphor. It can also be achieved by a light emitting device comprising a.

At this time, the amount of the green-based and orange-based phosphors included in the molding resin layer is preferably selected in the range of 70:30 to 95: 5.

The object of the present invention includes a light emitting device having a peak emission wavelength within a range of 400 nm to 450 nm, and a molding resin layer surrounding the light emitting device, wherein the molding resin layer includes a blue phosphor and a yellow phosphor. It can also be achieved by a light emitting device comprising a.

Herein, the amount of the blue-based and yellow-based phosphors included in the molding resin layer may be selected within a range of 20:80 to 70:30.

In this case, the molding resin layer may further include an orange-based fluorescent material, in this case, the amount of the blue-based, yellow-based and orange-based phosphors range from 20:70:10 to 70: 29: 1. Of course, it can be selected within.

Meanwhile, at least one of the yellow-based phosphors, the green-based phosphors, the orange-based phosphors, and the blue-based phosphors used in the above embodiments may be activated by Eu ²⁺ . It is preferable to configure the silicate (Orthosilicate) of the phosphor.

Hereinafter, with reference to the accompanying drawings will be described in detail the light emitting device of the present invention.

3 is a cross-sectional view of a lead type light emitting device according to the present invention. As can be seen from this figure, the light emitting device 1 includes a mount lead 3 and an inner lead 4. The light emitting element 7 is provided in the cup part 5 of the mount lid 3, and a molding resin layer 11 including a predetermined phosphor is formed on the upper portion of the cup portion 5 so as to surround the light emitting element 7. The n-side electrode and p-side electrode of the light emitting element 7 are connected to the mount lead 3 and the inner lead 4 via wires 13, respectively.

4 is a cross-sectional view of a chip type light emitting device according to the present invention. The light emitting device 21 shown in this figure is a light emitting device mounted on the printed circuit board 22 and the metal pad 23 and the lead 25 and the metal pad 23 provided on the printed circuit board 22. The element 7, the light emitting element 7, and a wire 13 connecting the lead 25 are provided. The apparatus further includes a molding resin layer 11 protruding onto the printed circuit board 22 and molded by partially including the lead 25 and the metal pad 23 with the light emitting device 7 interposed therebetween.

As the light emitting element 7 used in these light emitting devices 1 and 21, a blue series indium gallium nitride ((In, Ga) N) -based semiconductor or a compound semiconductor thereof can be used. In the present invention, among these indium gallium nitride-based semiconductors or compound semiconductors, those having a peak emission wavelength in the range of 400 nm to 450 nm are employed.

As the molding resin layer 11, a transparent resin excellent in weather resistance such as epoxy resin, urea resin, or silicone resin can be used. Then, the molding resin layer 11 functions to protect the light emitting element 7 and the wire 13 from the outside. The molding resin layer 11 may be deformed in various forms including a convex lens shape to increase its viewing angle.

On the other hand, the molding resin layer 11 includes at least two kinds of phosphors. Hereinafter, embodiments of the light emitting devices 1 and 21 according to the type of phosphor included in the molding resin layer 11 will be described. At this time, the light emitting elements 7 used in the light emitting devices 1 and 21 of the embodiments are the blue-based semiconductors as described above, and have a peak wavelength of 400 nm to 450 nm in common.

 <First Embodiment>

In the first embodiment, first, two kinds of phosphors are included in the molding resin layer 11. One is a yellow phosphor and the other is a green phosphor. Here, the yellow phosphor is an orthosilicate series activated by Eu ²⁺ , for example, x and y are properly adjusted to be yellow (Sr _1-xy , Ba _x , Ca _y ) ₂ A phosphor of SiO ₄ : Eu ²⁺ can be used. The control of color in such (Sr _1-xy , Ba _x , Ca _y ) ₂ SiO ₄ : Eu ²⁺ phosphors was published in November 1968 by Journal of the Korean Electrochemical Society, Vol. 115, No. 11, pp. 1181 to 1184 (Journal). of the Electro-Chemical Society, November 1968, Vol. 115, No. 11, page 1181-1184. In addition, the green phosphor is also an orthosilicate series activated by Eu ²⁺ , for example, x and y are appropriately adjusted to be green (Sr _1-xy , Ba _x , Ca _y ). Phosphors of ₂ SiO ₄ : Eu ²⁺ can be used.

In the present embodiment, on the other hand, it is preferable to appropriately adjust the quantitative ratio of the yellow-based phosphor and the green-based phosphor included in the molding resin layer 11. At this time, the quantitative ratio of the yellow-based and green-based phosphors may be selectively adopted within the range of 70:30 to 99: 1 (for example, 75:25, 80:20, etc.).

5 is a chromaticity diagram of a light emitting device having a molding resin layer including such a phosphor. Referring to the drawings, it can be seen that the color reproduction range (refer to the hatched portion) reproducible by the light emitting devices 1 and 21 according to the present embodiment is greatly enlarged compared with that of the light emitting device described with reference to FIG. Can be. In addition, it can be confirmed that the white reproduction range W1 distributed in the central portion of the enlarged color reproduction range is also greatly enlarged. Accordingly, this means that the light emitting devices 1 and 21 capable of reproducing white light having various chromaticities, colors, and the like can be provided.

The producer can be easily provided as a device for emitting any one side white light required by the user within the reproduction range of the expanded white light according to the present invention. The present light emitting devices 1 and 21 having improved color reproducibility can be easily applied to various products for lighting, and the light emitting efficiency thereof is very excellent. The present light emitting devices 1 and 21 having excellent luminous efficiency are particularly useful because they can be easily started for high brightness.

Second Embodiment

On the other hand, the phosphor included in the molding resin layer 11 may be added to the orange-based phosphor in addition to the yellow-based phosphor and the green-based phosphor. In this case, the quantitative constituent ratios of the phosphors of the yellow series, the green series and the orange series are in the range of 70:20:10 to 95: 4: 1 (for example, 75: 16.8: 8.2, 80: 13.6: 6.4). Here, as for the yellow-based phosphor and the green-based phosphor, an orthosilicate-based phosphor activated by Eu ²⁺ may be used as in the first embodiment.

Orange-based phosphors are also orthosilicates activated by Eu ²⁺ , for example (Sr _1-xy , Ba _x , Ca _y ) ₂ SiO ₄ with x and y properly adjusted to be orange. Phosphor of Eu ²⁺ can be used. Here, the orange-based phosphor serves to increase the component of the red region of the light emission spectrum formed by the light emitting devices 1 and 21. 6 is a graph showing light emission spectra of the light emitting device according to the second embodiment.

Referring to the drawings, it can be seen that the light emitting element 7 of the light emitting devices 1 and 21 has a light emission peak wavelength of 400 nm to 450 nm. In addition, the peak emission wavelength of the phosphor excited by the light emitting element 7 is shifted to around 600 nm in comparison with the conventional FIG. 1, so that the red light emission, that is, the emission from 650 nm to 700 nm It can be seen that. As a result, the light emitting devices 1 and 21 according to the present embodiment can adjust various chromaticities, colors, etc. of the white light by appropriately increasing or decreasing the components of the red region.

On the other hand, Fig. 7 is a chromaticity diagram of the light emitting device according to the second embodiment. As can be seen from this figure, the light-emitting devices 1 and 21 of this embodiment also have greatly expanded their color reproduction range (see the hatched portions), and their white light reproduction range W2 for their central portion has also been greatly expanded. You can check it. Therefore, the light emitting devices 1 and 21 of this embodiment can achieve the same objects and effects as those of the first embodiment related to Fig. 5 described above.

Third Embodiment

In the present embodiment, the molding resin layer 11 including only the green-based phosphor and the orange-based phosphor is provided. The quantitative ratio of the green-based phosphor and the orange-based phosphor can be appropriately selected within the range of 70:30 to 95: 5.

Then, in the light emitting devices 1 and 21 according to the present embodiment, the components of the red region are increased, as in the above-described second embodiment, and white light having various colors and colors can be reproduced. The emission spectrum is expressed as shown in FIG. Referring to the drawings, it can be seen that even in this embodiment, the entire color reproduction range has been enlarged, and the white light reproduction range W3 of the central portion thereof has also been enlarged. The effect thereby is the same as described above.

Fourth Example

In the present embodiment, a molding resin layer 11 including a blue phosphor and a yellow phosphor is provided. It is preferable that the quantitative ratio of the blue-based phosphor and the yellow-based phosphor is appropriately selected within the range of 20:80 to 70:30. Here, the blue-based phosphor, as in the phosphors described above, may be a phosphor activated by Eu ²⁺ , for example, a phosphor of BaMgAl ₁₄ O ₂₃ : Eu ²⁺ .

In the light emitting devices 1 and 21 according to the present embodiment, the light emitting element 7 having an emission peak wavelength of 400 nm to 450 nm performs only a function of exciting the phosphor. That is, the blue phosphor and the yellow phosphor are excited by the light emitting element 7 to emit light of a corresponding wavelength. The function of such a light emitting element is more effective when employing a light emission peak wavelength of 400nm to 420nm. In this configuration, white light is realized by diffusing and mixing the light generated in each phosphor.

9 is a chromaticity diagram of a light emitting device according to the present embodiment. Referring to the drawings, it is true that the color reproduction range W4 of this embodiment is narrow compared with that W of the first to third embodiments described above. However, a phosphor different from the conventional light emitting device is used, and in particular, it is different in a manner of implementing white light. The light emitting devices 1 and 21 according to the present embodiment also provide excellent luminous efficiency than conventional light emitting devices, and are easily applicable to high brightness products. In addition, the color reproduction ability is relatively excellent.

Fifth Embodiment

The light emitting devices 1 and 21 of the fifth embodiment according to the present invention further include an orange phosphor in addition to the blue phosphor and the yellow phosphor. Here, it is preferable that each phosphor uses an orthosilicate-based phosphor as described above activated by Eu ²⁺ . At this time, the quantitative ratio of the phosphors of the blue series, the yellow series and the orange series can be selectively employed within the range of 20:70:10 to 70: 29: 1.

Then, the light emitting devices 1 and 21 of this embodiment, although not shown the light emission spectrum thereof, have the same color component of the red region as in the second and third embodiments described above. At this time, the chromaticity diagram of this embodiment is expressed as can be seen in FIG. Referring to the drawings, the light emitting device can confirm that the color reproduction range (refer to the hatched portion) has been greatly enlarged, and it can also be confirmed that the white light reproduction range W5 of the central portion is also very wide. Accordingly, the effects of the present embodiment are the same as those of the above-described second and third embodiments, and the description thereof will be replaced by the above.

As described above, according to the present invention, by employing a light emitting device having a 400 nm to 450 nm light emission peak wavelength, by including predetermined phosphors in the molding resin layer surrounding these light emitting devices, their quantitative ratio is appropriately increased or decreased; There is provided a light emitting device in which the reproduction range of white light is greatly expanded. The light emitting device according to the present invention can be favorably applied to various lighting products, in particular, high brightness products, and also provides excellent light emission efficiency.

The light emitting device of the present invention also includes the predetermined phosphors in the molding resin layer, and by appropriately adjusting the quantitative ratio of the phosphors, the color component of the red region can be increased, thereby improving color rendering. Therefore, it can be used as a variety of lighting products and at the same time improve the color reproduction ability.

Claims (11)

delete delete delete delete delete delete A light emitting device having a peak emission wavelength in a range of 400 nm to 420 nm, A molding resin layer surrounding the light emitting device; The molding resin layer includes a blue-based phosphor and a yellow-based phosphor, The blue-based phosphor includes a BaMgAl ₁₄ O ₂₃ : Eu ²⁺ phosphor. The light emitting device of claim 7, wherein the amount of the blue-based and yellow-based phosphors is selective within a range of 20:80 to 70:30. The light emitting device of claim 7, wherein the molding resin layer further comprises an orange-based phosphor. 10. The light emitting device of claim 9, wherein the amount of the blue, yellow, and orange phosphors is selective within a range of 20:70:10 to 70: 29: 1. The light emitting device according to any one of claims 7 to 10, wherein at least one of the phosphors includes an orthosilicate series phosphor activated by Eu ²⁺ .

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